diff --git a/examples/expressions_explorer/public/actions_and_expressions.tsx b/examples/expressions_explorer/public/actions_and_expressions.tsx
index f802a78faf06..6d0c8886a79f 100644
--- a/examples/expressions_explorer/public/actions_and_expressions.tsx
+++ b/examples/expressions_explorer/public/actions_and_expressions.tsx
@@ -47,11 +47,11 @@ export function ActionsExpressionsExample({ expressions, actions }: Props) {
   };
 
   const handleEvents = (event: any) => {
-    if (event.id !== 'NAVIGATE') return;
+    if (event.name !== 'NAVIGATE') return;
     // enrich event context with some extra data
     event.baseUrl = 'http://www.google.com';
 
-    actions.executeTriggerActions(NAVIGATE_TRIGGER_ID, event.value);
+    actions.executeTriggerActions(NAVIGATE_TRIGGER_ID, event.data);
   };
 
   return (
diff --git a/examples/expressions_explorer/public/actions_and_expressions2.tsx b/examples/expressions_explorer/public/actions_and_expressions2.tsx
index 31ba903ad91a..e7dc28b8b97c 100644
--- a/examples/expressions_explorer/public/actions_and_expressions2.tsx
+++ b/examples/expressions_explorer/public/actions_and_expressions2.tsx
@@ -50,7 +50,7 @@ export function ActionsExpressionsExample2({ expressions, actions }: Props) {
   };
 
   const handleEvents = (event: any) => {
-    updateVariables({ color: event.value.href === 'http://www.google.com' ? 'red' : 'blue' });
+    updateVariables({ color: event.data.href === 'http://www.google.com' ? 'red' : 'blue' });
   };
 
   return (
diff --git a/examples/expressions_explorer/public/renderers/button.tsx b/examples/expressions_explorer/public/renderers/button.tsx
index 68add91c3cbc..557180ab73a3 100644
--- a/examples/expressions_explorer/public/renderers/button.tsx
+++ b/examples/expressions_explorer/public/renderers/button.tsx
@@ -18,8 +18,8 @@ export const buttonRenderer: ExpressionRenderDefinition<any> = {
   render(domNode, config, handlers) {
     const buttonClick = () => {
       handlers.event({
-        id: 'NAVIGATE',
-        value: {
+        name: 'NAVIGATE',
+        data: {
           href: config.href,
         },
       });
diff --git a/src/plugins/chart_expressions/expression_tagcloud/common/expression_functions/tagcloud_function.test.ts b/src/plugins/chart_expressions/expression_tagcloud/common/expression_functions/tagcloud_function.test.ts
index 8abdc36704b4..86a371afd691 100644
--- a/src/plugins/chart_expressions/expression_tagcloud/common/expression_functions/tagcloud_function.test.ts
+++ b/src/plugins/chart_expressions/expression_tagcloud/common/expression_functions/tagcloud_function.test.ts
@@ -12,6 +12,8 @@ import { functionWrapper } from '../../../../expressions/common/expression_funct
 import { ExpressionValueVisDimension } from '../../../../visualizations/public';
 import { Datatable } from '../../../../expressions/common/expression_types/specs';
 
+type Arguments = Parameters<ReturnType<typeof tagcloudFunction>['fn']>[1];
+
 describe('interpreter/functions#tagcloud', () => {
   const fn = functionWrapper(tagcloudFunction());
   const column1 = 'Count';
@@ -26,7 +28,7 @@ describe('interpreter/functions#tagcloud', () => {
       { [column1]: 0, [column2]: 'US' },
       { [column1]: 10, [column2]: 'UK' },
     ],
-  };
+  } as unknown as Datatable;
   const visConfig = {
     scale: 'linear',
     orientation: 'single',
@@ -73,12 +75,12 @@ describe('interpreter/functions#tagcloud', () => {
   };
 
   it('returns an object with the correct structure for number accessors', () => {
-    const actual = fn(context, { ...visConfig, ...numberAccessors }, undefined);
+    const actual = fn(context, { ...visConfig, ...numberAccessors } as Arguments, undefined);
     expect(actual).toMatchSnapshot();
   });
 
   it('returns an object with the correct structure for string accessors', () => {
-    const actual = fn(context, { ...visConfig, ...stringAccessors }, undefined);
+    const actual = fn(context, { ...visConfig, ...stringAccessors } as Arguments, undefined);
     expect(actual).toMatchSnapshot();
   });
 
@@ -93,7 +95,7 @@ describe('interpreter/functions#tagcloud', () => {
         },
       },
     };
-    await fn(context, { ...visConfig, ...numberAccessors }, handlers as any);
+    await fn(context, { ...visConfig, ...numberAccessors } as Arguments, handlers as any);
 
     expect(loggedTable!).toMatchSnapshot();
   });
diff --git a/src/plugins/expressions/.eslintrc.json b/src/plugins/expressions/.eslintrc.json
index 2aab6c2d9093..d1dbca41acc8 100644
--- a/src/plugins/expressions/.eslintrc.json
+++ b/src/plugins/expressions/.eslintrc.json
@@ -1,5 +1,6 @@
 {
   "rules": {
-    "@typescript-eslint/consistent-type-definitions": 0
+    "@typescript-eslint/consistent-type-definitions": 0,
+    "@typescript-eslint/no-explicit-any": ["error", { "ignoreRestArgs": true }]
   }
 }
diff --git a/src/plugins/expressions/common/ast/build_expression.ts b/src/plugins/expressions/common/ast/build_expression.ts
index 0f4618b3e699..6e84594022fd 100644
--- a/src/plugins/expressions/common/ast/build_expression.ts
+++ b/src/plugins/expressions/common/ast/build_expression.ts
@@ -32,13 +32,13 @@ import { parse } from './parse';
  * @param val Value you want to check.
  * @return boolean
  */
-export function isExpressionAstBuilder(val: any): val is ExpressionAstExpressionBuilder {
-  return val?.type === 'expression_builder';
+export function isExpressionAstBuilder(val: unknown): val is ExpressionAstExpressionBuilder {
+  return (val as Record<string, unknown> | undefined)?.type === 'expression_builder';
 }
 
 /** @internal */
-export function isExpressionAst(val: any): val is ExpressionAstExpression {
-  return val?.type === 'expression';
+export function isExpressionAst(val: unknown): val is ExpressionAstExpression {
+  return (val as Record<string, unknown> | undefined)?.type === 'expression';
 }
 
 export interface ExpressionAstExpressionBuilder {
diff --git a/src/plugins/expressions/common/ast/types.ts b/src/plugins/expressions/common/ast/types.ts
index e5a79a0a5dda..8f376ac547d2 100644
--- a/src/plugins/expressions/common/ast/types.ts
+++ b/src/plugins/expressions/common/ast/types.ts
@@ -64,7 +64,7 @@ export type ExpressionAstFunctionDebug = {
   /**
    * Raw error that was thrown by the function, if any.
    */
-  rawError?: any | Error;
+  rawError?: any | Error; // eslint-disable-line @typescript-eslint/no-explicit-any
 
   /**
    * Time in milliseconds it took to execute the function. Duration can be
diff --git a/src/plugins/expressions/common/execution/execution.abortion.test.ts b/src/plugins/expressions/common/execution/execution.abortion.test.ts
index 798558ba7ffb..fca030fb9a08 100644
--- a/src/plugins/expressions/common/execution/execution.abortion.test.ts
+++ b/src/plugins/expressions/common/execution/execution.abortion.test.ts
@@ -90,7 +90,7 @@ describe('Execution abortion tests', () => {
     const completed = jest.fn();
     const aborted = jest.fn();
 
-    const defer: ExpressionFunctionDefinition<'defer', any, { time: number }, any> = {
+    const defer: ExpressionFunctionDefinition<'defer', unknown, { time: number }, unknown> = {
       name: 'defer',
       args: {
         time: {
diff --git a/src/plugins/expressions/common/execution/execution.test.ts b/src/plugins/expressions/common/execution/execution.test.ts
index c478977f6076..9b889c62e9ff 100644
--- a/src/plugins/expressions/common/execution/execution.test.ts
+++ b/src/plugins/expressions/common/execution/execution.test.ts
@@ -17,7 +17,7 @@ import { ExecutionContract } from './execution_contract';
 
 beforeAll(() => {
   if (typeof performance === 'undefined') {
-    (global as any).performance = { now: Date.now };
+    global.performance = { now: Date.now } as typeof performance;
   }
 });
 
@@ -41,7 +41,7 @@ const createExecution = (
 const run = async (
   expression: string = 'foo bar=123',
   context?: Record<string, unknown>,
-  input: any = null
+  input: unknown = null
 ) => {
   const execution = createExecution(expression, context);
   execution.start(input);
@@ -262,45 +262,45 @@ describe('Execution', () => {
 
   describe('execution context', () => {
     test('context.variables is an object', async () => {
-      const { result } = (await run('introspectContext key="variables"')) as any;
+      const { result } = await run('introspectContext key="variables"');
 
       expect(result).toHaveProperty('result', expect.any(Object));
     });
 
     test('context.types is an object', async () => {
-      const { result } = (await run('introspectContext key="types"')) as any;
+      const { result } = await run('introspectContext key="types"');
 
       expect(result).toHaveProperty('result', expect.any(Object));
     });
 
     test('context.abortSignal is an object', async () => {
-      const { result } = (await run('introspectContext key="abortSignal"')) as any;
+      const { result } = await run('introspectContext key="abortSignal"');
 
       expect(result).toHaveProperty('result', expect.any(Object));
     });
 
     test('context.inspectorAdapters is an object', async () => {
-      const { result } = (await run('introspectContext key="inspectorAdapters"')) as any;
+      const { result } = await run('introspectContext key="inspectorAdapters"');
 
       expect(result).toHaveProperty('result', expect.any(Object));
     });
 
     test('context.getKibanaRequest is a function if provided', async () => {
-      const { result } = (await run('introspectContext key="getKibanaRequest"', {
+      const { result } = await run('introspectContext key="getKibanaRequest"', {
         kibanaRequest: {},
-      })) as any;
+      });
 
       expect(result).toHaveProperty('result', expect.any(Function));
     });
 
     test('context.getKibanaRequest is undefined if not provided', async () => {
-      const { result } = (await run('introspectContext key="getKibanaRequest"')) as any;
+      const { result } = await run('introspectContext key="getKibanaRequest"');
 
       expect(result).toHaveProperty('result', undefined);
     });
 
     test('unknown context key is undefined', async () => {
-      const { result } = (await run('introspectContext key="foo"')) as any;
+      const { result } = await run('introspectContext key="foo"');
 
       expect(result).toHaveProperty('result', undefined);
     });
@@ -314,7 +314,7 @@ describe('Execution', () => {
 
   describe('inspector adapters', () => {
     test('by default, "tables" and "requests" inspector adapters are available', async () => {
-      const { result } = (await run('introspectContext key="inspectorAdapters"')) as any;
+      const { result } = await run('introspectContext key="inspectorAdapters"');
       expect(result).toHaveProperty(
         'result',
         expect.objectContaining({
@@ -326,9 +326,9 @@ describe('Execution', () => {
 
     test('can set custom inspector adapters', async () => {
       const inspectorAdapters = {};
-      const { result } = (await run('introspectContext key="inspectorAdapters"', {
+      const { result } = await run('introspectContext key="inspectorAdapters"', {
         inspectorAdapters,
-      })) as any;
+      });
       expect(result).toHaveProperty('result', inspectorAdapters);
     });
 
@@ -351,7 +351,7 @@ describe('Execution', () => {
 
   describe('expression abortion', () => {
     test('context has abortSignal object', async () => {
-      const { result } = (await run('introspectContext key="abortSignal"')) as any;
+      const { result } = await run('introspectContext key="abortSignal"');
 
       expect(result).toHaveProperty('result.aborted', false);
     });
@@ -400,7 +400,7 @@ describe('Execution', () => {
       testScheduler.run(({ cold, expectObservable }) => {
         const arg = cold('     -a-b-c|', { a: 1, b: 2, c: 3 });
         const expected = '     -a-b-c|';
-        const observable: ExpressionFunctionDefinition<'observable', any, {}, any> = {
+        const observable: ExpressionFunctionDefinition<'observable', unknown, {}, unknown> = {
           name: 'observable',
           args: {},
           help: '',
@@ -468,7 +468,7 @@ describe('Execution', () => {
     });
 
     test('does not execute remaining functions in pipeline', async () => {
-      const spy: ExpressionFunctionDefinition<'spy', any, {}, any> = {
+      const spy: ExpressionFunctionDefinition<'spy', unknown, {}, unknown> = {
         name: 'spy',
         args: {},
         help: '',
@@ -621,7 +621,12 @@ describe('Execution', () => {
           help: '',
           fn: () => arg2,
         };
-        const max: ExpressionFunctionDefinition<'max', any, { val1: number; val2: number }, any> = {
+        const max: ExpressionFunctionDefinition<
+          'max',
+          unknown,
+          { val1: number; val2: number },
+          unknown
+        > = {
           name: 'max',
           args: {
             val1: { help: '', types: ['number'] },
@@ -679,7 +684,12 @@ describe('Execution', () => {
 
   describe('when arguments are missing', () => {
     it('when required argument is missing and has not alias, returns error', async () => {
-      const requiredArg: ExpressionFunctionDefinition<'requiredArg', any, { arg: any }, any> = {
+      const requiredArg: ExpressionFunctionDefinition<
+        'requiredArg',
+        unknown,
+        { arg: unknown },
+        unknown
+      > = {
         name: 'requiredArg',
         args: {
           arg: {
diff --git a/src/plugins/expressions/common/execution/execution.ts b/src/plugins/expressions/common/execution/execution.ts
index 0bb12951202a..54a4800ec7c3 100644
--- a/src/plugins/expressions/common/execution/execution.ts
+++ b/src/plugins/expressions/common/execution/execution.ts
@@ -8,6 +8,7 @@
 
 import { i18n } from '@kbn/i18n';
 import { isPromise } from '@kbn/std';
+import { ObservableLike, UnwrapObservable, UnwrapPromiseOrReturn } from '@kbn/utility-types';
 import { keys, last, mapValues, reduce, zipObject } from 'lodash';
 import {
   combineLatest,
@@ -44,6 +45,18 @@ import { ExecutionContract } from './execution_contract';
 import { ExpressionExecutionParams } from '../service';
 import { createDefaultInspectorAdapters } from '../util/create_default_inspector_adapters';
 
+type UnwrapReturnType<Function extends (...args: any[]) => unknown> =
+  ReturnType<Function> extends ObservableLike<unknown>
+    ? UnwrapObservable<ReturnType<Function>>
+    : UnwrapPromiseOrReturn<ReturnType<Function>>;
+
+// type ArgumentsOf<Function extends ExpressionFunction> = Function extends ExpressionFunction<
+//   unknown,
+//   infer Arguments
+// >
+//   ? Arguments
+//   : never;
+
 /**
  * The result returned after an expression function execution.
  */
@@ -83,7 +96,7 @@ const createAbortErrorValue = () =>
   });
 
 export interface ExecutionParams {
-  executor: Executor<any>;
+  executor: Executor;
   ast?: ExpressionAstExpression;
   expression?: string;
   params: ExpressionExecutionParams;
@@ -107,7 +120,7 @@ export class Execution<
    * N.B. It is initialized to `null` rather than `undefined` for legacy reasons,
    * because in legacy interpreter it was set to `null` by default.
    */
-  public input: Input = null as any;
+  public input = null as unknown as Input;
 
   /**
    * Input of the started execution.
@@ -186,13 +199,13 @@ export class Execution<
     });
 
     const inspectorAdapters =
-      execution.params.inspectorAdapters || createDefaultInspectorAdapters();
+      (execution.params.inspectorAdapters as InspectorAdapters) || createDefaultInspectorAdapters();
 
     this.context = {
       getSearchContext: () => this.execution.params.searchContext || {},
       getSearchSessionId: () => execution.params.searchSessionId,
       getKibanaRequest: execution.params.kibanaRequest
-        ? () => execution.params.kibanaRequest
+        ? () => execution.params.kibanaRequest!
         : undefined,
       variables: execution.params.variables || {},
       types: executor.getTypes(),
@@ -201,14 +214,14 @@ export class Execution<
       logDatatable: (name: string, datatable: Datatable) => {
         inspectorAdapters.tables[name] = datatable;
       },
-      isSyncColorsEnabled: () => execution.params.syncColors,
-      ...(execution.params as any).extraContext,
+      isSyncColorsEnabled: () => execution.params.syncColors!,
+      ...execution.params.extraContext,
       getExecutionContext: () => execution.params.executionContext,
     };
 
     this.result = this.input$.pipe(
       switchMap((input) =>
-        this.race(this.invokeChain(this.state.get().ast.chain, input)).pipe(
+        this.race(this.invokeChain<Output>(this.state.get().ast.chain, input)).pipe(
           (source) =>
             new Observable<ExecutionResult<Output>>((subscriber) => {
               let latest: ExecutionResult<Output> | undefined;
@@ -270,8 +283,8 @@ export class Execution<
    * N.B. `input` is initialized to `null` rather than `undefined` for legacy reasons,
    * because in legacy interpreter it was set to `null` by default.
    */
-  public start(
-    input: Input = null as any,
+  start(
+    input = null as unknown as Input,
     isSubExpression?: boolean
   ): Observable<ExecutionResult<Output | ExpressionValueError>> {
     if (this.hasStarted) throw new Error('Execution already started.');
@@ -294,7 +307,10 @@ export class Execution<
     return this.result;
   }
 
-  invokeChain(chainArr: ExpressionAstFunction[], input: unknown): Observable<any> {
+  invokeChain<ChainOutput = unknown>(
+    chainArr: ExpressionAstFunction[],
+    input: unknown
+  ): Observable<ChainOutput> {
     return of(input).pipe(
       ...(chainArr.map((link) =>
         switchMap((currentInput) => {
@@ -364,19 +380,24 @@ export class Execution<
         })
       ) as Parameters<Observable<unknown>['pipe']>),
       catchError((error) => of(error))
-    );
+    ) as Observable<ChainOutput>;
   }
 
-  invokeFunction(
-    fn: ExpressionFunction,
+  invokeFunction<Fn extends ExpressionFunction>(
+    fn: Fn,
     input: unknown,
     args: Record<string, unknown>
-  ): Observable<any> {
+  ): Observable<UnwrapReturnType<Fn['fn']>> {
     return of(input).pipe(
       map((currentInput) => this.cast(currentInput, fn.inputTypes)),
       switchMap((normalizedInput) => this.race(of(fn.fn(normalizedInput, args, this.context)))),
-      switchMap((fnResult: any) =>
-        isObservable(fnResult) ? fnResult : from(isPromise(fnResult) ? fnResult : [fnResult])
+      switchMap(
+        (fnResult) =>
+          (isObservable(fnResult)
+            ? fnResult
+            : from(isPromise(fnResult) ? fnResult : [fnResult])) as Observable<
+            UnwrapReturnType<Fn['fn']>
+          >
       ),
       map((output) => {
         // Validate that the function returned the type it said it would.
@@ -405,39 +426,49 @@ export class Execution<
     );
   }
 
-  public cast(value: any, toTypeNames?: string[]) {
+  public cast<Type = unknown>(value: unknown, toTypeNames?: string[]): Type {
     // If you don't give us anything to cast to, you'll get your input back
-    if (!toTypeNames || toTypeNames.length === 0) return value;
+    if (!toTypeNames?.length) {
+      return value as Type;
+    }
 
     // No need to cast if node is already one of the valid types
     const fromTypeName = getType(value);
-    if (toTypeNames.includes(fromTypeName)) return value;
+    if (toTypeNames.includes(fromTypeName)) {
+      return value as Type;
+    }
 
     const { types } = this.state.get();
     const fromTypeDef = types[fromTypeName];
 
     for (const toTypeName of toTypeNames) {
       // First check if the current type can cast to this type
-      if (fromTypeDef && fromTypeDef.castsTo(toTypeName)) {
+      if (fromTypeDef?.castsTo(toTypeName)) {
         return fromTypeDef.to(value, toTypeName, types);
       }
 
       // If that isn't possible, check if this type can cast from the current type
       const toTypeDef = types[toTypeName];
-      if (toTypeDef && toTypeDef.castsFrom(fromTypeName)) return toTypeDef.from(value, types);
+      if (toTypeDef?.castsFrom(fromTypeName)) {
+        return toTypeDef.from(value, types);
+      }
     }
 
     throw new Error(`Can not cast '${fromTypeName}' to any of '${toTypeNames.join(', ')}'`);
   }
 
   // Processes the multi-valued AST argument values into arguments that can be passed to the function
-  resolveArgs(fnDef: ExpressionFunction, input: unknown, argAsts: any): Observable<any> {
+  resolveArgs<Fn extends ExpressionFunction>(
+    fnDef: Fn,
+    input: unknown,
+    argAsts: Record<string, ExpressionAstArgument[]>
+  ): Observable<Record<string, unknown>> {
     return defer(() => {
       const { args: argDefs } = fnDef;
 
       // Use the non-alias name from the argument definition
       const dealiasedArgAsts = reduce(
-        argAsts as Record<string, ExpressionAstArgument>,
+        argAsts,
         (acc, argAst, argName) => {
           const argDef = getByAlias(argDefs, argName);
           if (!argDef) {
@@ -452,7 +483,7 @@ export class Execution<
       // Check for missing required arguments.
       for (const { aliases, default: argDefault, name, required } of Object.values(argDefs)) {
         if (!(name in dealiasedArgAsts) && typeof argDefault !== 'undefined') {
-          dealiasedArgAsts[name] = [parse(argDefault, 'argument')];
+          dealiasedArgAsts[name] = [parse(argDefault as string, 'argument')];
         }
 
         if (!required || name in dealiasedArgAsts) {
@@ -490,7 +521,7 @@ export class Execution<
       const argNames = keys(resolveArgFns);
 
       if (!argNames.length) {
-        return from([[]]);
+        return from([{}]);
       }
 
       const resolvedArgValuesObservable = combineLatest(
@@ -523,7 +554,7 @@ export class Execution<
     });
   }
 
-  public interpret<T>(ast: ExpressionAstNode, input: T): Observable<ExecutionResult<unknown>> {
+  interpret<T>(ast: ExpressionAstNode, input: T): Observable<ExecutionResult<unknown>> {
     switch (getType(ast)) {
       case 'expression':
         const execution = this.execution.executor.createExecution(
diff --git a/src/plugins/expressions/common/execution/types.ts b/src/plugins/expressions/common/execution/types.ts
index 06eac98feba6..9264891b2e0b 100644
--- a/src/plugins/expressions/common/execution/types.ts
+++ b/src/plugins/expressions/common/execution/types.ts
@@ -11,7 +11,7 @@ import type { SerializableRecord } from '@kbn/utility-types';
 import type { KibanaRequest } from 'src/core/server';
 import type { KibanaExecutionContext } from 'src/core/public';
 
-import { ExpressionType } from '../expression_types';
+import { Datatable, ExpressionType } from '../expression_types';
 import { Adapters, RequestAdapter } from '../../../inspector/common';
 import { TablesAdapter } from '../util/tables_adapter';
 
@@ -69,6 +69,11 @@ export interface ExecutionContext<
    * Contains the meta-data about the source of the expression.
    */
   getExecutionContext: () => KibanaExecutionContext | undefined;
+
+  /**
+   * Logs datatable.
+   */
+  logDatatable?(name: string, datatable: Datatable): void;
 }
 
 /**
diff --git a/src/plugins/expressions/common/executor/container.ts b/src/plugins/expressions/common/executor/container.ts
index 9d3796ac64f4..c8e24974126f 100644
--- a/src/plugins/expressions/common/executor/container.ts
+++ b/src/plugins/expressions/common/executor/container.ts
@@ -19,7 +19,7 @@ export interface ExecutorState<Context extends Record<string, unknown> = Record<
   context: Context;
 }
 
-export const defaultState: ExecutorState<any> = {
+export const defaultState: ExecutorState = {
   functions: {},
   types: {},
   context: {},
@@ -61,7 +61,7 @@ export type ExecutorContainer<Context extends Record<string, unknown> = Record<s
 export const createExecutorContainer = <
   Context extends Record<string, unknown> = Record<string, unknown>
 >(
-  state: ExecutorState<Context> = defaultState
+  state = defaultState as ExecutorState<Context>
 ): ExecutorContainer<Context> => {
   const container = createStateContainer<
     ExecutorState<Context>,
diff --git a/src/plugins/expressions/common/executor/executor.execution.test.ts b/src/plugins/expressions/common/executor/executor.execution.test.ts
index 38022c0f7dc4..ad7e6e6a014c 100644
--- a/src/plugins/expressions/common/executor/executor.execution.test.ts
+++ b/src/plugins/expressions/common/executor/executor.execution.test.ts
@@ -8,20 +8,14 @@
 
 import { Executor } from './executor';
 import { parseExpression } from '../ast';
+import { Execution } from '../execution/execution';
 
-// eslint-disable-next-line
-const { __getArgs } = require('../execution/execution');
+jest.mock('../execution/execution', () => ({
+  Execution: jest.fn(),
+}));
 
-jest.mock('../execution/execution', () => {
-  const mockedModule = {
-    args: undefined,
-    __getArgs: () => mockedModule.args,
-    Execution: function ExecutionMock(...args: any) {
-      mockedModule.args = args;
-    },
-  };
-
-  return mockedModule;
+beforeEach(() => {
+  jest.clearAllMocks();
 });
 
 describe('Executor mocked execution tests', () => {
@@ -31,7 +25,9 @@ describe('Executor mocked execution tests', () => {
         const executor = new Executor();
         executor.createExecution('foo bar="baz"');
 
-        expect(__getArgs()[0].expression).toBe('foo bar="baz"');
+        expect(Execution).toHaveBeenCalledWith(
+          expect.objectContaining({ expression: 'foo bar="baz"' })
+        );
       });
     });
 
@@ -41,7 +37,9 @@ describe('Executor mocked execution tests', () => {
         const ast = parseExpression('foo bar="baz"');
         executor.createExecution(ast);
 
-        expect(__getArgs()[0].expression).toBe(undefined);
+        expect(Execution).toHaveBeenCalledWith(
+          expect.not.objectContaining({ expression: expect.anything() })
+        );
       });
     });
   });
diff --git a/src/plugins/expressions/common/executor/executor.test.ts b/src/plugins/expressions/common/executor/executor.test.ts
index 4a3d6045a7b4..60f0f0da4e15 100644
--- a/src/plugins/expressions/common/executor/executor.test.ts
+++ b/src/plugins/expressions/common/executor/executor.test.ts
@@ -145,7 +145,7 @@ describe('Executor', () => {
         executor.extendContext({ foo });
         const execution = executor.createExecution('foo bar="baz"');
 
-        expect((execution.context as any).foo).toBe(foo);
+        expect(execution.context).toHaveProperty('foo', foo);
       });
     });
   });
@@ -175,10 +175,10 @@ describe('Executor', () => {
       migrations: {
         '7.10.0': ((state: ExpressionAstFunction, version: string): ExpressionAstFunction => {
           return migrateFn(state, version);
-        }) as any as MigrateFunction,
+        }) as unknown as MigrateFunction,
         '7.10.1': ((state: ExpressionAstFunction, version: string): ExpressionAstFunction => {
           return migrateFn(state, version);
-        }) as any as MigrateFunction,
+        }) as unknown as MigrateFunction,
       },
       fn: jest.fn(),
     };
diff --git a/src/plugins/expressions/common/executor/executor.ts b/src/plugins/expressions/common/executor/executor.ts
index ce411ea94eaf..f4913c4953ba 100644
--- a/src/plugins/expressions/common/executor/executor.ts
+++ b/src/plugins/expressions/common/executor/executor.ts
@@ -40,7 +40,7 @@ export interface ExpressionExecOptions {
 }
 
 export class TypesRegistry implements IRegistry<ExpressionType> {
-  constructor(private readonly executor: Executor<any>) {}
+  constructor(private readonly executor: Executor) {}
 
   public register(
     typeDefinition: AnyExpressionTypeDefinition | (() => AnyExpressionTypeDefinition)
@@ -62,7 +62,7 @@ export class TypesRegistry implements IRegistry<ExpressionType> {
 }
 
 export class FunctionsRegistry implements IRegistry<ExpressionFunction> {
-  constructor(private readonly executor: Executor<any>) {}
+  constructor(private readonly executor: Executor) {}
 
   public register(
     functionDefinition: AnyExpressionFunctionDefinition | (() => AnyExpressionFunctionDefinition)
@@ -100,12 +100,12 @@ export class Executor<Context extends Record<string, unknown> = Record<string, u
   /**
    * @deprecated
    */
-  public readonly functions = new FunctionsRegistry(this);
+  public readonly functions = new FunctionsRegistry(this as Executor);
 
   /**
    * @deprecated
    */
-  public readonly types = new TypesRegistry(this);
+  public readonly types = new TypesRegistry(this as Executor);
 
   protected parent?: Executor<Context>;
 
@@ -207,15 +207,15 @@ export class Executor<Context extends Record<string, unknown> = Record<string, u
     ast: string | ExpressionAstExpression,
     params: ExpressionExecutionParams = {}
   ): Execution<Input, Output> {
-    const executionParams: ExecutionParams = {
+    const executionParams = {
       executor: this,
       params: {
         ...params,
         // for canvas we are passing this in,
         // canvas should be refactored to not pass any extra context in
         extraContext: this.context,
-      } as any,
-    };
+      },
+    } as ExecutionParams;
 
     if (typeof ast === 'string') executionParams.expression = ast;
     else executionParams.ast = ast;
@@ -273,7 +273,7 @@ export class Executor<Context extends Record<string, unknown> = Record<string, u
     return { state: newAst, references: allReferences };
   }
 
-  public telemetry(ast: ExpressionAstExpression, telemetryData: Record<string, any>) {
+  public telemetry(ast: ExpressionAstExpression, telemetryData: Record<string, unknown>) {
     this.walkAst(cloneDeep(ast), (fn, link) => {
       telemetryData = fn.telemetry(link.arguments, telemetryData);
     });
diff --git a/src/plugins/expressions/common/expression_functions/arguments.ts b/src/plugins/expressions/common/expression_functions/arguments.ts
index 67f83cabc645..7e39f019f00c 100644
--- a/src/plugins/expressions/common/expression_functions/arguments.ts
+++ b/src/plugins/expressions/common/expression_functions/arguments.ts
@@ -24,9 +24,9 @@ export type ArgumentType<T> =
  * representation of the type.
  */
 // prettier-ignore
-type ArrayTypeToArgumentString<T> = 
-  T extends Array<infer ElementType> ? TypeString<ElementType> : 
-  T extends null ? 'null' : 
+type ArrayTypeToArgumentString<T> =
+  T extends Array<infer ElementType> ? TypeString<ElementType> :
+  T extends null ? 'null' :
   never;
 
 /**
@@ -34,9 +34,9 @@ type ArrayTypeToArgumentString<T> =
  * string-based representation of the return type.
  */
 // prettier-ignore
-type UnresolvedTypeToArgumentString<T> = 
-  T extends (...args: any) => infer ElementType ? TypeString<ElementType> : 
-  T extends null ? 'null' : 
+type UnresolvedTypeToArgumentString<T> =
+  T extends (...args: any[]) => infer ElementType ? TypeString<ElementType> :
+  T extends null ? 'null' :
   never;
 
 /**
@@ -44,10 +44,10 @@ type UnresolvedTypeToArgumentString<T> =
  * string-based representation of the return type.
  */
 // prettier-ignore
-type UnresolvedArrayTypeToArgumentString<T> = 
-  T extends Array<(...args: any) => infer ElementType> ? TypeString<ElementType> :
-  T extends (...args: any) => infer ElementType ? ArrayTypeToArgumentString<ElementType> : 
-  T extends null ? 'null' : 
+type UnresolvedArrayTypeToArgumentString<T> =
+  T extends Array<(...args: any[]) => infer ElementType> ? TypeString<ElementType> :
+  T extends (...args: any[]) => infer ElementType ? ArrayTypeToArgumentString<ElementType> :
+  T extends null ? 'null' :
   never;
 
 /** A type containing properties common to all Function Arguments. */
diff --git a/src/plugins/expressions/common/expression_functions/expression_function.ts b/src/plugins/expressions/common/expression_functions/expression_function.ts
index 05a5dbb638c0..8154534b32ab 100644
--- a/src/plugins/expressions/common/expression_functions/expression_function.ts
+++ b/src/plugins/expressions/common/expression_functions/expression_function.ts
@@ -36,7 +36,11 @@ export class ExpressionFunction implements PersistableState<ExpressionAstFunctio
   /**
    * Function to run function (context, args)
    */
-  fn: (input: ExpressionValue, params: Record<string, any>, handlers: object) => ExpressionValue;
+  fn: (
+    input: ExpressionValue,
+    params: Record<string, unknown>,
+    handlers: object
+  ) => ExpressionValue;
 
   /**
    * A short help text.
@@ -56,8 +60,8 @@ export class ExpressionFunction implements PersistableState<ExpressionAstFunctio
   disabled: boolean;
   telemetry: (
     state: ExpressionAstFunction['arguments'],
-    telemetryData: Record<string, any>
-  ) => Record<string, any>;
+    telemetryData: Record<string, unknown>
+  ) => Record<string, unknown>;
   extract: (state: ExpressionAstFunction['arguments']) => {
     state: ExpressionAstFunction['arguments'];
     references: SavedObjectReference[];
@@ -100,13 +104,12 @@ export class ExpressionFunction implements PersistableState<ExpressionAstFunctio
     this.migrations = migrations || {};
 
     for (const [key, arg] of Object.entries(args || {})) {
-      this.args[key] = new ExpressionFunctionParameter(key, arg);
+      this.args[key as keyof typeof args] = new ExpressionFunctionParameter(key, arg);
     }
   }
 
   accepts = (type: string): boolean => {
     // If you don't tell us input types, we'll assume you don't care what you get.
-    if (!this.inputTypes) return true;
-    return this.inputTypes.indexOf(type) > -1;
+    return this.inputTypes?.includes(type) ?? true;
   };
 }
diff --git a/src/plugins/expressions/common/expression_functions/expression_function_parameter.ts b/src/plugins/expressions/common/expression_functions/expression_function_parameter.ts
index bfc45d65f1c9..9942c9af7ff7 100644
--- a/src/plugins/expressions/common/expression_functions/expression_function_parameter.ts
+++ b/src/plugins/expressions/common/expression_functions/expression_function_parameter.ts
@@ -6,20 +6,21 @@
  * Side Public License, v 1.
  */
 
+import { KnownTypeToString } from '../types';
 import { ArgumentType } from './arguments';
 
-export class ExpressionFunctionParameter {
+export class ExpressionFunctionParameter<T = unknown> {
   name: string;
   required: boolean;
   help: string;
-  types: string[];
-  default: any;
+  types: ArgumentType<T>['types'];
+  default?: ArgumentType<T>['default'];
   aliases: string[];
   multi: boolean;
   resolve: boolean;
-  options: any[];
+  options: T[];
 
-  constructor(name: string, arg: ArgumentType<any>) {
+  constructor(name: string, arg: ArgumentType<T>) {
     const { required, help, types, aliases, multi, resolve, options } = arg;
 
     if (name === '_') {
@@ -38,7 +39,6 @@ export class ExpressionFunctionParameter {
   }
 
   accepts(type: string) {
-    if (!this.types.length) return true;
-    return this.types.indexOf(type) > -1;
+    return !this.types?.length || this.types.includes(type as KnownTypeToString<T>);
   }
 }
diff --git a/src/plugins/expressions/common/expression_functions/expression_function_parameters.test.ts b/src/plugins/expressions/common/expression_functions/expression_function_parameters.test.ts
index 6e47634f5aac..28ef5243e0fe 100644
--- a/src/plugins/expressions/common/expression_functions/expression_function_parameters.test.ts
+++ b/src/plugins/expressions/common/expression_functions/expression_function_parameters.test.ts
@@ -21,7 +21,7 @@ describe('ExpressionFunctionParameter', () => {
     const param = new ExpressionFunctionParameter('foo', {
       help: 'bar',
       types: ['baz', 'quux'],
-    });
+    } as ConstructorParameters<typeof ExpressionFunctionParameter>[1]);
 
     expect(param.accepts('baz')).toBe(true);
     expect(param.accepts('quux')).toBe(true);
diff --git a/src/plugins/expressions/common/expression_functions/specs/create_table.ts b/src/plugins/expressions/common/expression_functions/specs/create_table.ts
index 5174b258a4d9..0ce427e817e2 100644
--- a/src/plugins/expressions/common/expression_functions/specs/create_table.ts
+++ b/src/plugins/expressions/common/expression_functions/specs/create_table.ts
@@ -11,9 +11,9 @@ import { ExpressionFunctionDefinition } from '../types';
 import { Datatable, DatatableColumn } from '../../expression_types';
 
 export interface CreateTableArguments {
-  ids: string[];
-  names: string[] | null;
-  rowCount: number;
+  ids?: string[];
+  names?: string[] | null;
+  rowCount?: number;
 }
 
 export const createTable: ExpressionFunctionDefinition<
diff --git a/src/plugins/expressions/common/expression_functions/specs/font.ts b/src/plugins/expressions/common/expression_functions/specs/font.ts
index fa8fc8d387af..3d189a68119d 100644
--- a/src/plugins/expressions/common/expression_functions/specs/font.ts
+++ b/src/plugins/expressions/common/expression_functions/specs/font.ts
@@ -30,7 +30,7 @@ const inlineStyle = (obj: Record<string, string | number>) => {
   return styles.join(';');
 };
 
-interface Arguments {
+export interface FontArguments {
   align?: TextAlignment;
   color?: string;
   family?: FontFamily;
@@ -41,7 +41,12 @@ interface Arguments {
   weight?: FontWeight;
 }
 
-export type ExpressionFunctionFont = ExpressionFunctionDefinition<'font', null, Arguments, Style>;
+export type ExpressionFunctionFont = ExpressionFunctionDefinition<
+  'font',
+  null,
+  FontArguments,
+  Style
+>;
 
 export const font: ExpressionFunctionFont = {
   name: 'font',
diff --git a/src/plugins/expressions/common/expression_functions/specs/map_column.ts b/src/plugins/expressions/common/expression_functions/specs/map_column.ts
index 23aeee6f9581..7b2266637bfb 100644
--- a/src/plugins/expressions/common/expression_functions/specs/map_column.ts
+++ b/src/plugins/expressions/common/expression_functions/specs/map_column.ts
@@ -110,7 +110,7 @@ export const mapColumn: ExpressionFunctionDefinition<
       map((rows) => {
         let type: DatatableColumnType = 'null';
         for (const row of rows) {
-          const rowType = getType(row[id]);
+          const rowType = getType(row[id]) as DatatableColumnType;
           if (rowType !== 'null') {
             type = rowType;
             break;
diff --git a/src/plugins/expressions/common/expression_functions/specs/math.ts b/src/plugins/expressions/common/expression_functions/specs/math.ts
index 92a10976428a..f843f53e4dd8 100644
--- a/src/plugins/expressions/common/expression_functions/specs/math.ts
+++ b/src/plugins/expressions/common/expression_functions/specs/math.ts
@@ -6,7 +6,7 @@
  * Side Public License, v 1.
  */
 
-import { map, zipObject } from 'lodash';
+import { map, zipObject, isString } from 'lodash';
 import { i18n } from '@kbn/i18n';
 import { evaluate } from '@kbn/tinymath';
 import { ExpressionFunctionDefinition } from '../types';
@@ -23,19 +23,18 @@ const TINYMATH = '`TinyMath`';
 const TINYMATH_URL =
   'https://www.elastic.co/guide/en/kibana/current/canvas-tinymath-functions.html';
 
-const isString = (val: any): boolean => typeof val === 'string';
-
 function pivotObjectArray<
-  RowType extends { [key: string]: any },
-  ReturnColumns extends string | number | symbol = keyof RowType
->(rows: RowType[], columns?: string[]): Record<string, ReturnColumns[]> {
+  RowType extends { [key: string]: unknown },
+  ReturnColumns extends keyof RowType & string
+>(rows: RowType[], columns?: ReturnColumns[]) {
   const columnNames = columns || Object.keys(rows[0]);
   if (!columnNames.every(isString)) {
     throw new Error('Columns should be an array of strings');
   }
 
   const columnValues = map(columnNames, (name) => map(rows, name));
-  return zipObject(columnNames, columnValues);
+
+  return zipObject(columnNames, columnValues) as { [K in ReturnColumns]: Array<RowType[K]> };
 }
 
 export const errors = {
diff --git a/src/plugins/expressions/common/expression_functions/specs/math_column.ts b/src/plugins/expressions/common/expression_functions/specs/math_column.ts
index c59016cd260a..a2a79ef3f028 100644
--- a/src/plugins/expressions/common/expression_functions/specs/math_column.ts
+++ b/src/plugins/expressions/common/expression_functions/specs/math_column.ts
@@ -107,7 +107,7 @@ export const mathColumn: ExpressionFunctionDefinition<
     let type: DatatableColumnType = 'null';
     if (newRows.length) {
       for (const row of newRows) {
-        const rowType = getType(row[args.id]);
+        const rowType = getType(row[args.id]) as DatatableColumnType;
         if (rowType !== 'null') {
           type = rowType;
           break;
diff --git a/src/plugins/expressions/common/expression_functions/specs/tests/font.test.ts b/src/plugins/expressions/common/expression_functions/specs/tests/font.test.ts
index 03b610126660..e095f4e1bec6 100644
--- a/src/plugins/expressions/common/expression_functions/specs/tests/font.test.ts
+++ b/src/plugins/expressions/common/expression_functions/specs/tests/font.test.ts
@@ -7,7 +7,8 @@
  */
 
 import { openSans } from '../../../fonts';
-import { font } from '../font';
+import { FontWeight, TextAlignment } from '../../../types';
+import { font, FontArguments } from '../font';
 import { functionWrapper } from './utils';
 
 describe('font', () => {
@@ -22,7 +23,7 @@ describe('font', () => {
     size: 14,
     underline: false,
     weight: 'normal',
-  };
+  } as unknown as FontArguments;
 
   describe('default output', () => {
     const result = fn(null, args);
@@ -63,7 +64,7 @@ describe('font', () => {
 
     describe('family', () => {
       it('sets font family', () => {
-        const result = fn(null, { ...args, family: 'Optima, serif' });
+        const result = fn(null, { ...args, family: 'Optima, serif' } as unknown as FontArguments);
         expect(result.spec.fontFamily).toBe('Optima, serif');
         expect(result.css).toContain('font-family:Optima, serif');
       });
@@ -79,29 +80,29 @@ describe('font', () => {
 
     describe('weight', () => {
       it('sets font weight', () => {
-        let result = fn(null, { ...args, weight: 'normal' });
+        let result = fn(null, { ...args, weight: FontWeight.NORMAL });
         expect(result.spec.fontWeight).toBe('normal');
         expect(result.css).toContain('font-weight:normal');
 
-        result = fn(null, { ...args, weight: 'bold' });
+        result = fn(null, { ...args, weight: FontWeight.BOLD });
         expect(result.spec.fontWeight).toBe('bold');
         expect(result.css).toContain('font-weight:bold');
 
-        result = fn(null, { ...args, weight: 'bolder' });
+        result = fn(null, { ...args, weight: FontWeight.BOLDER });
         expect(result.spec.fontWeight).toBe('bolder');
         expect(result.css).toContain('font-weight:bolder');
 
-        result = fn(null, { ...args, weight: 'lighter' });
+        result = fn(null, { ...args, weight: FontWeight.LIGHTER });
         expect(result.spec.fontWeight).toBe('lighter');
         expect(result.css).toContain('font-weight:lighter');
 
-        result = fn(null, { ...args, weight: '400' });
+        result = fn(null, { ...args, weight: FontWeight.FOUR });
         expect(result.spec.fontWeight).toBe('400');
         expect(result.css).toContain('font-weight:400');
       });
 
       it('throws when provided an invalid weight', () => {
-        expect(() => fn(null, { ...args, weight: 'foo' })).toThrow();
+        expect(() => fn(null, { ...args, weight: 'foo' as FontWeight })).toThrow();
       });
     });
 
@@ -131,25 +132,25 @@ describe('font', () => {
 
     describe('align', () => {
       it('sets text alignment', () => {
-        let result = fn(null, { ...args, align: 'left' });
+        let result = fn(null, { ...args, align: TextAlignment.LEFT });
         expect(result.spec.textAlign).toBe('left');
         expect(result.css).toContain('text-align:left');
 
-        result = fn(null, { ...args, align: 'center' });
+        result = fn(null, { ...args, align: TextAlignment.CENTER });
         expect(result.spec.textAlign).toBe('center');
         expect(result.css).toContain('text-align:center');
 
-        result = fn(null, { ...args, align: 'right' });
+        result = fn(null, { ...args, align: TextAlignment.RIGHT });
         expect(result.spec.textAlign).toBe('right');
         expect(result.css).toContain('text-align:right');
 
-        result = fn(null, { ...args, align: 'justify' });
+        result = fn(null, { ...args, align: TextAlignment.JUSTIFY });
         expect(result.spec.textAlign).toBe('justify');
         expect(result.css).toContain('text-align:justify');
       });
 
       it('throws when provided an invalid alignment', () => {
-        expect(() => fn(null, { ...args, align: 'foo' })).toThrow();
+        expect(() => fn(null, { ...args, align: 'foo' as TextAlignment })).toThrow();
       });
     });
   });
diff --git a/src/plugins/expressions/common/expression_functions/specs/tests/math.test.ts b/src/plugins/expressions/common/expression_functions/specs/tests/math.test.ts
index 6da00061244d..3761fe0a4f90 100644
--- a/src/plugins/expressions/common/expression_functions/specs/tests/math.test.ts
+++ b/src/plugins/expressions/common/expression_functions/specs/tests/math.test.ts
@@ -6,19 +6,19 @@
  * Side Public License, v 1.
  */
 
-import { errors, math } from '../math';
+import { errors, math, MathArguments, MathInput } from '../math';
 import { emptyTable, functionWrapper, testTable } from './utils';
 
 describe('math', () => {
-  const fn = functionWrapper<unknown>(math);
+  const fn = functionWrapper(math);
 
   it('evaluates math expressions without reference to context', () => {
-    expect(fn(null, { expression: '10.5345' })).toBe(10.5345);
-    expect(fn(null, { expression: '123 + 456' })).toBe(579);
-    expect(fn(null, { expression: '100 - 46' })).toBe(54);
+    expect(fn(null as unknown as MathInput, { expression: '10.5345' })).toBe(10.5345);
+    expect(fn(null as unknown as MathInput, { expression: '123 + 456' })).toBe(579);
+    expect(fn(null as unknown as MathInput, { expression: '100 - 46' })).toBe(54);
     expect(fn(1, { expression: '100 / 5' })).toBe(20);
-    expect(fn('foo', { expression: '100 / 5' })).toBe(20);
-    expect(fn(true, { expression: '100 / 5' })).toBe(20);
+    expect(fn('foo' as unknown as MathInput, { expression: '100 / 5' })).toBe(20);
+    expect(fn(true as unknown as MathInput, { expression: '100 / 5' })).toBe(20);
     expect(fn(testTable, { expression: '100 * 5' })).toBe(500);
     expect(fn(emptyTable, { expression: '100 * 5' })).toBe(500);
   });
@@ -54,7 +54,7 @@ describe('math', () => {
   describe('args', () => {
     describe('expression', () => {
       it('sets the math expression to be evaluted', () => {
-        expect(fn(null, { expression: '10' })).toBe(10);
+        expect(fn(null as unknown as MathInput, { expression: '10' })).toBe(10);
         expect(fn(23.23, { expression: 'floor(value)' })).toBe(23);
         expect(fn(testTable, { expression: 'count(price)' })).toBe(9);
         expect(fn(testTable, { expression: 'count(name)' })).toBe(9);
@@ -99,11 +99,11 @@ describe('math', () => {
     it('throws when missing expression', () => {
       expect(() => fn(testTable)).toThrow(new RegExp(errors.emptyExpression().message));
 
-      expect(() => fn(testTable, { expession: '' })).toThrow(
+      expect(() => fn(testTable, { expession: '' } as unknown as MathArguments)).toThrow(
         new RegExp(errors.emptyExpression().message)
       );
 
-      expect(() => fn(testTable, { expession: ' ' })).toThrow(
+      expect(() => fn(testTable, { expession: ' ' } as unknown as MathArguments)).toThrow(
         new RegExp(errors.emptyExpression().message)
       );
     });
diff --git a/src/plugins/expressions/common/expression_functions/specs/tests/theme.test.ts b/src/plugins/expressions/common/expression_functions/specs/tests/theme.test.ts
index 0733b1c77bf4..3f535b7fb7ac 100644
--- a/src/plugins/expressions/common/expression_functions/specs/tests/theme.test.ts
+++ b/src/plugins/expressions/common/expression_functions/specs/tests/theme.test.ts
@@ -26,14 +26,14 @@ describe('expression_functions', () => {
       };
 
       context = {
-        getSearchContext: () => ({} as any),
+        getSearchContext: () => ({}),
         getSearchSessionId: () => undefined,
         getExecutionContext: () => undefined,
         types: {},
         variables: { theme: themeProps },
-        abortSignal: {} as any,
-        inspectorAdapters: {} as any,
-      };
+        abortSignal: {},
+        inspectorAdapters: {},
+      } as unknown as typeof context;
     });
 
     it('returns the selected variable', () => {
diff --git a/src/plugins/expressions/common/expression_functions/specs/tests/ui_setting.test.ts b/src/plugins/expressions/common/expression_functions/specs/tests/ui_setting.test.ts
index 6b3a458aa7e5..053f97ffc8fb 100644
--- a/src/plugins/expressions/common/expression_functions/specs/tests/ui_setting.test.ts
+++ b/src/plugins/expressions/common/expression_functions/specs/tests/ui_setting.test.ts
@@ -10,13 +10,15 @@ jest.mock('../../../../common');
 
 import { IUiSettingsClient } from 'src/core/public';
 import { getUiSettingFn } from '../ui_setting';
+import { functionWrapper } from './utils';
 
 describe('uiSetting', () => {
   describe('fn', () => {
     let getStartDependencies: jest.MockedFunction<
       Parameters<typeof getUiSettingFn>[0]['getStartDependencies']
     >;
-    let uiSetting: ReturnType<typeof getUiSettingFn>;
+    const uiSettingWrapper = () => functionWrapper(getUiSettingFn({ getStartDependencies }));
+    let uiSetting: ReturnType<typeof uiSettingWrapper>;
     let uiSettings: jest.Mocked<IUiSettingsClient>;
 
     beforeEach(() => {
@@ -27,13 +29,13 @@ describe('uiSetting', () => {
         uiSettings,
       })) as unknown as typeof getStartDependencies;
 
-      uiSetting = getUiSettingFn({ getStartDependencies });
+      uiSetting = uiSettingWrapper();
     });
 
     it('should return a value', () => {
       uiSettings.get.mockReturnValueOnce('value');
 
-      expect(uiSetting.fn(null, { parameter: 'something' }, {} as any)).resolves.toEqual({
+      expect(uiSetting(null, { parameter: 'something' })).resolves.toEqual({
         type: 'ui_setting',
         key: 'something',
         value: 'value',
@@ -41,7 +43,7 @@ describe('uiSetting', () => {
     });
 
     it('should pass a default value', async () => {
-      await uiSetting.fn(null, { parameter: 'something', default: 'default' }, {} as any);
+      await uiSetting(null, { parameter: 'something', default: 'default' });
 
       expect(uiSettings.get).toHaveBeenCalledWith('something', 'default');
     });
@@ -51,16 +53,16 @@ describe('uiSetting', () => {
         throw new Error();
       });
 
-      expect(uiSetting.fn(null, { parameter: 'something' }, {} as any)).rejects.toEqual(
+      expect(uiSetting(null, { parameter: 'something' })).rejects.toEqual(
         new Error('Invalid parameter "something".')
       );
     });
 
     it('should get a request instance on the server-side', async () => {
       const request = {};
-      await uiSetting.fn(null, { parameter: 'something' }, {
+      await uiSetting(null, { parameter: 'something' }, {
         getKibanaRequest: () => request,
-      } as any);
+      } as Parameters<typeof uiSetting>[2]);
 
       const [[getKibanaRequest]] = getStartDependencies.mock.calls;
 
@@ -68,7 +70,7 @@ describe('uiSetting', () => {
     });
 
     it('should throw an error if request is not provided on the server-side', async () => {
-      await uiSetting.fn(null, { parameter: 'something' }, {} as any);
+      await uiSetting(null, { parameter: 'something' });
 
       const [[getKibanaRequest]] = getStartDependencies.mock.calls;
 
diff --git a/src/plugins/expressions/common/expression_functions/specs/tests/utils.ts b/src/plugins/expressions/common/expression_functions/specs/tests/utils.ts
index ca41b427a28f..e3f581d1ae35 100644
--- a/src/plugins/expressions/common/expression_functions/specs/tests/utils.ts
+++ b/src/plugins/expressions/common/expression_functions/specs/tests/utils.ts
@@ -15,13 +15,15 @@ import { Datatable } from '../../../expression_types';
  * Takes a function spec and passes in default args,
  * overriding with any provided args.
  */
-export const functionWrapper = <ContextType = object | null>(
-  spec: AnyExpressionFunctionDefinition
+export const functionWrapper = <
+  ExpressionFunctionDefinition extends AnyExpressionFunctionDefinition
+>(
+  spec: ExpressionFunctionDefinition
 ) => {
   const defaultArgs = mapValues(spec.args, (argSpec) => argSpec.default);
   return (
-    context: ContextType,
-    args: Record<string, any> = {},
+    context?: Parameters<ExpressionFunctionDefinition['fn']>[0] | null,
+    args: Parameters<ExpressionFunctionDefinition['fn']>[1] = {},
     handlers: ExecutionContext = {} as ExecutionContext
   ) => spec.fn(context, { ...defaultArgs, ...args }, handlers);
 };
diff --git a/src/plugins/expressions/common/expression_functions/specs/tests/var.test.ts b/src/plugins/expressions/common/expression_functions/specs/tests/var.test.ts
index 0c5c6b148020..ca9c9c257f70 100644
--- a/src/plugins/expressions/common/expression_functions/specs/tests/var.test.ts
+++ b/src/plugins/expressions/common/expression_functions/specs/tests/var.test.ts
@@ -24,9 +24,9 @@ describe('expression_functions', () => {
         getExecutionContext: () => undefined,
         types: {},
         variables: { test: 1 },
-        abortSignal: {} as any,
-        inspectorAdapters: {} as any,
-      };
+        abortSignal: {},
+        inspectorAdapters: {},
+      } as unknown as typeof context;
     });
 
     it('returns the selected variable', () => {
diff --git a/src/plugins/expressions/common/expression_functions/specs/tests/var_set.test.ts b/src/plugins/expressions/common/expression_functions/specs/tests/var_set.test.ts
index 95287f71907a..b98e8285a1a8 100644
--- a/src/plugins/expressions/common/expression_functions/specs/tests/var_set.test.ts
+++ b/src/plugins/expressions/common/expression_functions/specs/tests/var_set.test.ts
@@ -17,7 +17,7 @@ describe('expression_functions', () => {
     const fn = functionWrapper(variableSet);
     let input: Partial<ReturnType<ExecutionContext['getSearchContext']>>;
     let context: ExecutionContext;
-    let variables: Record<string, any>;
+    let variables: Record<string, unknown>;
 
     beforeEach(() => {
       input = { timeRange: { from: '0', to: '1' } };
@@ -27,9 +27,9 @@ describe('expression_functions', () => {
         getExecutionContext: () => undefined,
         types: {},
         variables: { test: 1 },
-        abortSignal: {} as any,
-        inspectorAdapters: {} as any,
-      };
+        abortSignal: {},
+        inspectorAdapters: {},
+      } as unknown as typeof context;
 
       variables = context.variables;
     });
diff --git a/src/plugins/expressions/common/expression_functions/specs/theme.ts b/src/plugins/expressions/common/expression_functions/specs/theme.ts
index 914e5d330bdd..76e97b12a967 100644
--- a/src/plugins/expressions/common/expression_functions/specs/theme.ts
+++ b/src/plugins/expressions/common/expression_functions/specs/theme.ts
@@ -12,10 +12,10 @@ import { ExpressionFunctionDefinition } from '../types';
 
 interface Arguments {
   variable: string;
-  default: string | number | boolean;
+  default?: string | number | boolean;
 }
 
-type Output = any;
+type Output = unknown;
 
 export type ExpressionFunctionTheme = ExpressionFunctionDefinition<
   'theme',
diff --git a/src/plugins/expressions/common/expression_functions/specs/var.ts b/src/plugins/expressions/common/expression_functions/specs/var.ts
index d0e43a687147..0ba4d5f43935 100644
--- a/src/plugins/expressions/common/expression_functions/specs/var.ts
+++ b/src/plugins/expressions/common/expression_functions/specs/var.ts
@@ -36,7 +36,8 @@ export const variable: ExpressionFunctionVar = {
     },
   },
   fn(input, args, context) {
-    const variables: Record<string, any> = context.variables;
+    const { variables } = context;
+
     return variables[args.name];
   },
 };
diff --git a/src/plugins/expressions/common/expression_functions/specs/var_set.ts b/src/plugins/expressions/common/expression_functions/specs/var_set.ts
index f3ac6a2ab80d..aa257940f9ad 100644
--- a/src/plugins/expressions/common/expression_functions/specs/var_set.ts
+++ b/src/plugins/expressions/common/expression_functions/specs/var_set.ts
@@ -7,11 +7,12 @@
  */
 
 import { i18n } from '@kbn/i18n';
+import type { Serializable } from '@kbn/utility-types';
 import { ExpressionFunctionDefinition } from '../types';
 
 interface Arguments {
   name: string[];
-  value: any[];
+  value: Serializable[];
 }
 
 export type ExpressionFunctionVarSet = ExpressionFunctionDefinition<
@@ -46,10 +47,11 @@ export const variableSet: ExpressionFunctionVarSet = {
     },
   },
   fn(input, args, context) {
-    const variables: Record<string, any> = context.variables;
+    const { variables } = context;
     args.name.forEach((name, i) => {
       variables[name] = args.value[i] === undefined ? input : args.value[i];
     });
+
     return input;
   },
 };
diff --git a/src/plugins/expressions/common/expression_functions/types.ts b/src/plugins/expressions/common/expression_functions/types.ts
index 0ec61b39608a..cb3677ed1668 100644
--- a/src/plugins/expressions/common/expression_functions/types.ts
+++ b/src/plugins/expressions/common/expression_functions/types.ts
@@ -30,7 +30,7 @@ import { PersistableStateDefinition } from '../../../kibana_utils/common';
 export interface ExpressionFunctionDefinition<
   Name extends string,
   Input,
-  Arguments extends Record<string, any>,
+  Arguments extends Record<keyof unknown, unknown>,
   Output,
   Context extends ExecutionContext = ExecutionContext
 > extends PersistableStateDefinition<ExpressionAstFunction['arguments']> {
@@ -99,12 +99,14 @@ export interface ExpressionFunctionDefinition<
 /**
  * Type to capture every possible expression function definition.
  */
+/* eslint-disable @typescript-eslint/no-explicit-any */
 export type AnyExpressionFunctionDefinition = ExpressionFunctionDefinition<
   string,
   any,
   Record<string, any>,
   any
 >;
+/* eslint-enable @typescript-eslint/no-explicit-any */
 
 /**
  * A mapping of `ExpressionFunctionDefinition`s for functions which the
diff --git a/src/plugins/expressions/common/expression_renderers/types.ts b/src/plugins/expressions/common/expression_renderers/types.ts
index 8547c1a1bec9..6c889a81a1f8 100644
--- a/src/plugins/expressions/common/expression_renderers/types.ts
+++ b/src/plugins/expressions/common/expression_renderers/types.ts
@@ -6,6 +6,8 @@
  * Side Public License, v 1.
  */
 
+import { ExpressionAstExpression } from '../ast';
+
 export interface ExpressionRenderDefinition<Config = unknown> {
   /**
    * Technical name of the renderer, used as ID to identify renderer in
@@ -46,6 +48,7 @@ export interface ExpressionRenderDefinition<Config = unknown> {
   ) => void | Promise<void>;
 }
 
+// eslint-disable-next-line @typescript-eslint/no-explicit-any
 export type AnyExpressionRenderDefinition = ExpressionRenderDefinition<any>;
 
 /**
@@ -59,24 +62,34 @@ export type AnyExpressionRenderDefinition = ExpressionRenderDefinition<any>;
  */
 export type RenderMode = 'edit' | 'preview' | 'view';
 
+export interface IInterpreterRenderUpdateParams<Params = unknown> {
+  newExpression?: string | ExpressionAstExpression;
+  newParams: Params;
+}
+
+export interface IInterpreterRenderEvent<Context = unknown> {
+  name: string;
+  data?: Context;
+}
+
 export interface IInterpreterRenderHandlers {
   /**
    * Done increments the number of rendering successes
    */
-  done: () => void;
-  onDestroy: (fn: () => void) => void;
-  reload: () => void;
-  update: (params: any) => void;
-  event: (event: any) => void;
-  hasCompatibleActions?: (event: any) => Promise<boolean>;
-  getRenderMode: () => RenderMode;
+  done(): void;
+  onDestroy(fn: () => void): void;
+  reload(): void;
+  update(params: IInterpreterRenderUpdateParams): void;
+  event(event: IInterpreterRenderEvent): void;
+  hasCompatibleActions?(event: IInterpreterRenderEvent): Promise<boolean>;
+  getRenderMode(): RenderMode;
 
   /**
    * The chart is rendered in a non-interactive environment and should not provide any affordances for interaction like brushing.
    */
-  isInteractive: () => boolean;
+  isInteractive(): boolean;
 
-  isSyncColorsEnabled: () => boolean;
+  isSyncColorsEnabled(): boolean;
   /**
    * This uiState interface is actually `PersistedState` from the visualizations plugin,
    * but expressions cannot know about vis or it creates a mess of circular dependencies.
diff --git a/src/plugins/expressions/common/expression_types/expression_type.ts b/src/plugins/expressions/common/expression_types/expression_type.ts
index 1c22b9f13b97..d179beeb7686 100644
--- a/src/plugins/expressions/common/expression_types/expression_type.ts
+++ b/src/plugins/expressions/common/expression_types/expression_type.ts
@@ -6,6 +6,7 @@
  * Side Public License, v 1.
  */
 
+import type { Serializable } from '@kbn/utility-types';
 import { AnyExpressionTypeDefinition, ExpressionValue, ExpressionValueConverter } from './types';
 import { getType } from './get_type';
 
@@ -20,15 +21,15 @@ export class ExpressionType {
   /**
    * Type validation, useful for checking function output.
    */
-  validate: (type: any) => void | Error;
+  validate: (type: unknown) => void | Error;
 
   create: unknown;
 
   /**
    * Optional serialization (used when passing context around client/server).
    */
-  serialize?: (value: ExpressionValue) => any;
-  deserialize?: (serialized: any) => ExpressionValue;
+  serialize?: (value: Serializable) => unknown;
+  deserialize?: (serialized: unknown[]) => Serializable;
 
   constructor(private readonly definition: AnyExpressionTypeDefinition) {
     const { name, help, deserialize, serialize, validate } = definition;
@@ -38,7 +39,7 @@ export class ExpressionType {
     this.validate = validate || (() => {});
 
     // Optional
-    this.create = (definition as any).create;
+    this.create = (definition as unknown as Record<'create', unknown>).create;
 
     this.serialize = serialize;
     this.deserialize = deserialize;
diff --git a/src/plugins/expressions/common/expression_types/get_type.ts b/src/plugins/expressions/common/expression_types/get_type.ts
index 052508df4132..17089c78816b 100644
--- a/src/plugins/expressions/common/expression_types/get_type.ts
+++ b/src/plugins/expressions/common/expression_types/get_type.ts
@@ -6,14 +6,24 @@
  * Side Public License, v 1.
  */
 
-export function getType(node: any) {
-  if (node == null) return 'null';
+export function getType(node: unknown): string {
+  if (node == null) {
+    return 'null';
+  }
+
   if (Array.isArray(node)) {
     throw new Error('Unexpected array value encountered.');
   }
-  if (typeof node === 'object') {
-    if (!node.type) throw new Error('Objects must have a type property');
-    return node.type;
+
+  if (typeof node !== 'object') {
+    return typeof node;
   }
-  return typeof node;
+
+  const { type } = node as Record<string, unknown>;
+
+  if (!type) {
+    throw new Error('Objects must have a type property');
+  }
+
+  return type as string;
 }
diff --git a/src/plugins/expressions/common/expression_types/specs/datatable.ts b/src/plugins/expressions/common/expression_types/specs/datatable.ts
index c268557936ac..b45c36950f87 100644
--- a/src/plugins/expressions/common/expression_types/specs/datatable.ts
+++ b/src/plugins/expressions/common/expression_types/specs/datatable.ts
@@ -9,7 +9,7 @@
 import type { SerializableRecord } from '@kbn/utility-types';
 import { map, pick, zipObject } from 'lodash';
 
-import { ExpressionTypeDefinition } from '../types';
+import { ExpressionTypeDefinition, ExpressionValueBoxed } from '../types';
 import { PointSeries, PointSeriesColumn } from './pointseries';
 import { ExpressionValueRender } from './render';
 import { SerializedFieldFormat } from '../../types';
@@ -21,7 +21,7 @@ const name = 'datatable';
  * @param datatable
  */
 export const isDatatable = (datatable: unknown): datatable is Datatable =>
-  !!datatable && typeof datatable === 'object' && (datatable as any).type === 'datatable';
+  (datatable as ExpressionValueBoxed | undefined)?.type === 'datatable';
 
 /**
  * This type represents the `type` of any `DatatableColumn` in a `Datatable`.
@@ -48,6 +48,7 @@ export type DatatableColumnType =
 /**
  * This type represents a row in a `Datatable`.
  */
+// eslint-disable-next-line @typescript-eslint/no-explicit-any
 export type DatatableRow = Record<string, any>;
 
 /**
@@ -112,7 +113,7 @@ interface RenderedDatatable {
 
 export const datatable: ExpressionTypeDefinition<typeof name, Datatable, SerializedDatatable> = {
   name,
-  validate: (table) => {
+  validate: (table: Record<string, unknown>) => {
     // TODO: Check columns types. Only string, boolean, number, date, allowed for now.
     if (!table.columns) {
       throw new Error('datatable must have a columns array, even if it is empty');
diff --git a/src/plugins/expressions/common/expression_types/specs/error.ts b/src/plugins/expressions/common/expression_types/specs/error.ts
index 75e49633866f..b170675b8f48 100644
--- a/src/plugins/expressions/common/expression_types/specs/error.ts
+++ b/src/plugins/expressions/common/expression_types/specs/error.ts
@@ -22,7 +22,7 @@ export type ExpressionValueError = ExpressionValueBoxed<
   }
 >;
 
-export const isExpressionValueError = (value: any): value is ExpressionValueError =>
+export const isExpressionValueError = (value: unknown): value is ExpressionValueError =>
   getType(value) === 'error';
 
 /**
diff --git a/src/plugins/expressions/common/expression_types/specs/pointseries.ts b/src/plugins/expressions/common/expression_types/specs/pointseries.ts
index 1c8bddf14cff..ef2079bd387a 100644
--- a/src/plugins/expressions/common/expression_types/specs/pointseries.ts
+++ b/src/plugins/expressions/common/expression_types/specs/pointseries.ts
@@ -7,7 +7,7 @@
  */
 
 import { ExpressionTypeDefinition, ExpressionValueBoxed } from '../types';
-import { Datatable } from './datatable';
+import { Datatable, DatatableRow } from './datatable';
 import { ExpressionValueRender } from './render';
 
 const name = 'pointseries';
@@ -31,7 +31,7 @@ export interface PointSeriesColumn {
  */
 export type PointSeriesColumns = Record<PointSeriesColumnName, PointSeriesColumn> | {};
 
-export type PointSeriesRow = Record<string, any>;
+export type PointSeriesRow = DatatableRow;
 
 /**
  * A `PointSeries` is a unique structure that represents dots on a chart.
diff --git a/src/plugins/expressions/common/expression_types/specs/shape.ts b/src/plugins/expressions/common/expression_types/specs/shape.ts
index 2b62dc6458c1..5ad86366a26c 100644
--- a/src/plugins/expressions/common/expression_types/specs/shape.ts
+++ b/src/plugins/expressions/common/expression_types/specs/shape.ts
@@ -11,7 +11,7 @@ import { ExpressionValueRender } from './render';
 
 const name = 'shape';
 
-export const shape: ExpressionTypeDefinition<typeof name, ExpressionValueRender<any>> = {
+export const shape: ExpressionTypeDefinition<typeof name, ExpressionValueRender<unknown>> = {
   name: 'shape',
   to: {
     render: (input) => {
diff --git a/src/plugins/expressions/common/expression_types/types.ts b/src/plugins/expressions/common/expression_types/types.ts
index a829c2adc923..15ec82e40314 100644
--- a/src/plugins/expressions/common/expression_types/types.ts
+++ b/src/plugins/expressions/common/expression_types/types.ts
@@ -6,6 +6,9 @@
  * Side Public License, v 1.
  */
 
+import type { ExpressionType } from './expression_type';
+
+// eslint-disable-next-line @typescript-eslint/no-explicit-any
 export type ExpressionValueUnboxed = any;
 
 export type ExpressionValueBoxed<Type extends string = string, Value extends object = object> = {
@@ -16,7 +19,7 @@ export type ExpressionValue = ExpressionValueUnboxed | ExpressionValueBoxed;
 
 export type ExpressionValueConverter<I extends ExpressionValue, O extends ExpressionValue> = (
   input: I,
-  availableTypes: Record<string, any>
+  availableTypes: Record<string, ExpressionType>
 ) => O;
 
 /**
@@ -29,18 +32,19 @@ export interface ExpressionTypeDefinition<
   SerializedType = undefined
 > {
   name: Name;
-  validate?: (type: any) => void | Error;
-  serialize?: (type: Value) => SerializedType;
-  deserialize?: (type: SerializedType) => Value;
+  validate?(type: unknown): void | Error;
+  serialize?(type: Value): SerializedType;
+  deserialize?(type: SerializedType): Value;
   // TODO: Update typings for the `availableTypes` parameter once interfaces for this
   // have been added elsewhere in the interpreter.
   from?: {
-    [type: string]: ExpressionValueConverter<any, Value>;
+    [type: string]: ExpressionValueConverter<ExpressionValue, Value>;
   };
   to?: {
-    [type: string]: ExpressionValueConverter<Value, any>;
+    [type: string]: ExpressionValueConverter<Value, ExpressionValue>;
   };
   help?: string;
 }
 
-export type AnyExpressionTypeDefinition = ExpressionTypeDefinition<any, any, any>;
+// eslint-disable-next-line @typescript-eslint/no-explicit-any
+export type AnyExpressionTypeDefinition = ExpressionTypeDefinition<string, any, any>;
diff --git a/src/plugins/expressions/common/mocks.ts b/src/plugins/expressions/common/mocks.ts
index 681fa2826882..4141da06ec04 100644
--- a/src/plugins/expressions/common/mocks.ts
+++ b/src/plugins/expressions/common/mocks.ts
@@ -11,7 +11,7 @@ import { ExecutionContext } from './execution/types';
 export const createMockExecutionContext = <ExtraContext extends object = object>(
   extraContext: ExtraContext = {} as ExtraContext
 ): ExecutionContext & ExtraContext => {
-  const executionContext: ExecutionContext = {
+  const executionContext = {
     getSearchContext: jest.fn(),
     getSearchSessionId: jest.fn(),
     getExecutionContext: jest.fn(),
@@ -25,10 +25,10 @@ export const createMockExecutionContext = <ExtraContext extends object = object>
       removeEventListener: jest.fn(),
     },
     inspectorAdapters: {
-      requests: {} as any,
-      data: {} as any,
+      requests: {},
+      data: {},
     },
-  };
+  } as unknown as ExecutionContext;
 
   return {
     ...executionContext,
diff --git a/src/plugins/expressions/common/service/expressions_services.ts b/src/plugins/expressions/common/service/expressions_services.ts
index f21eaa34d786..453ea656ec43 100644
--- a/src/plugins/expressions/common/service/expressions_services.ts
+++ b/src/plugins/expressions/common/service/expressions_services.ts
@@ -125,7 +125,7 @@ export interface ExpressionsServiceSetup {
 export interface ExpressionExecutionParams {
   searchContext?: SerializableRecord;
 
-  variables?: Record<string, any>;
+  variables?: Record<string, unknown>;
 
   /**
    * Whether to execute expression in *debug mode*. In *debug mode* inputs and
@@ -148,6 +148,8 @@ export interface ExpressionExecutionParams {
   inspectorAdapters?: Adapters;
 
   executionContext?: KibanaExecutionContext;
+
+  extraContext?: object;
 }
 
 /**
@@ -375,7 +377,7 @@ export class ExpressionsService
    */
   public readonly telemetry = (
     state: ExpressionAstExpression,
-    telemetryData: Record<string, any> = {}
+    telemetryData: Record<string, unknown> = {}
   ) => {
     return this.executor.telemetry(state, telemetryData);
   };
diff --git a/src/plugins/expressions/common/test_helpers/expression_functions/access.ts b/src/plugins/expressions/common/test_helpers/expression_functions/access.ts
index 5498e6741bd9..6ddc99b13ee5 100644
--- a/src/plugins/expressions/common/test_helpers/expression_functions/access.ts
+++ b/src/plugins/expressions/common/test_helpers/expression_functions/access.ts
@@ -8,7 +8,7 @@
 
 import { ExpressionFunctionDefinition } from '../../expression_functions';
 
-export const access: ExpressionFunctionDefinition<'access', any, { key: string }, any> = {
+export const access: ExpressionFunctionDefinition<'access', unknown, { key: string }, unknown> = {
   name: 'access',
   help: 'Access key on input object or return the input, if it is not an object',
   args: {
@@ -19,6 +19,10 @@ export const access: ExpressionFunctionDefinition<'access', any, { key: string }
     },
   },
   fn: (input, { key }, context) => {
-    return !input ? input : typeof input === 'object' ? input[key] : input;
+    return !input
+      ? input
+      : typeof input === 'object'
+      ? (input as Record<string, unknown>)[key]
+      : input;
   },
 };
diff --git a/src/plugins/expressions/common/test_helpers/expression_functions/add.ts b/src/plugins/expressions/common/test_helpers/expression_functions/add.ts
index 03c72733166b..5e646ead7b62 100644
--- a/src/plugins/expressions/common/test_helpers/expression_functions/add.ts
+++ b/src/plugins/expressions/common/test_helpers/expression_functions/add.ts
@@ -26,11 +26,11 @@ export const add: ExpressionFunctionDefinition<
       types: ['null', 'number', 'string'],
     },
   },
-  fn: ({ value: value1 }, { val: input2 }, context) => {
+  fn: ({ value: value1 }, { val: input2 }) => {
     const value2 = !input2
       ? 0
       : typeof input2 === 'object'
-      ? (input2 as any).value
+      ? (input2 as ExpressionValueNum).value
       : Number(input2);
 
     return {
diff --git a/src/plugins/expressions/common/test_helpers/expression_functions/introspect_context.ts b/src/plugins/expressions/common/test_helpers/expression_functions/introspect_context.ts
index 9556872d5734..8b2c22df8e08 100644
--- a/src/plugins/expressions/common/test_helpers/expression_functions/introspect_context.ts
+++ b/src/plugins/expressions/common/test_helpers/expression_functions/introspect_context.ts
@@ -10,9 +10,9 @@ import { ExpressionFunctionDefinition } from '../../expression_functions';
 
 export const introspectContext: ExpressionFunctionDefinition<
   'introspectContext',
-  any,
+  unknown,
   { key: string },
-  any
+  unknown
 > = {
   name: 'introspectContext',
   args: {
@@ -25,7 +25,7 @@ export const introspectContext: ExpressionFunctionDefinition<
   fn: (input, args, context) => {
     return {
       type: 'any',
-      result: (context as any)[args.key],
+      result: context[args.key as keyof typeof context],
     };
   },
 };
diff --git a/src/plugins/expressions/common/test_helpers/expression_functions/sleep.ts b/src/plugins/expressions/common/test_helpers/expression_functions/sleep.ts
index 04b1c9822a3b..71a14b3dac10 100644
--- a/src/plugins/expressions/common/test_helpers/expression_functions/sleep.ts
+++ b/src/plugins/expressions/common/test_helpers/expression_functions/sleep.ts
@@ -8,7 +8,7 @@
 
 import { ExpressionFunctionDefinition } from '../../expression_functions';
 
-export const sleep: ExpressionFunctionDefinition<'sleep', any, { time: number }, any> = {
+export const sleep: ExpressionFunctionDefinition<'sleep', unknown, { time: number }, unknown> = {
   name: 'sleep',
   args: {
     time: {
diff --git a/src/plugins/expressions/common/types/common.ts b/src/plugins/expressions/common/types/common.ts
index d8d1a9a4b256..64b3d00895f5 100644
--- a/src/plugins/expressions/common/types/common.ts
+++ b/src/plugins/expressions/common/types/common.ts
@@ -37,7 +37,7 @@ export type KnownTypeToString<T> =
  * `someArgument: Promise<boolean | string>` results in `types: ['boolean', 'string']`
  */
 export type TypeString<T> = KnownTypeToString<
-  T extends ObservableLike<any> ? UnwrapObservable<T> : UnwrapPromiseOrReturn<T>
+  T extends ObservableLike<unknown> ? UnwrapObservable<T> : UnwrapPromiseOrReturn<T>
 >;
 
 /**
@@ -52,6 +52,7 @@ export type UnmappedTypeStrings = 'date' | 'filter';
  * Is used to carry information about how to format data in
  * a data table as part of the column definition.
  */
+// eslint-disable-next-line @typescript-eslint/no-explicit-any
 export interface SerializedFieldFormat<TParams = Record<string, any>> {
   id?: string;
   params?: TParams;
diff --git a/src/plugins/expressions/common/util/expressions_inspector_adapter.ts b/src/plugins/expressions/common/util/expressions_inspector_adapter.ts
index 34fa1c8713f5..bf16635792c1 100644
--- a/src/plugins/expressions/common/util/expressions_inspector_adapter.ts
+++ b/src/plugins/expressions/common/util/expressions_inspector_adapter.ts
@@ -7,16 +7,17 @@
  */
 
 import { EventEmitter } from 'events';
+import { ExpressionAstNode } from '..';
 
 export class ExpressionsInspectorAdapter extends EventEmitter {
-  private _ast: any = {};
+  private _ast = {} as ExpressionAstNode;
 
-  public logAST(ast: any): void {
+  logAST(ast: ExpressionAstNode): void {
     this._ast = ast;
     this.emit('change', this._ast);
   }
 
-  public get ast() {
+  public get ast(): ExpressionAstNode {
     return this._ast;
   }
 }
diff --git a/src/plugins/expressions/common/util/test_utils.ts b/src/plugins/expressions/common/util/test_utils.ts
index 59bd0a4235d9..a6a4771bdf89 100644
--- a/src/plugins/expressions/common/util/test_utils.ts
+++ b/src/plugins/expressions/common/util/test_utils.ts
@@ -14,7 +14,7 @@ export const createMockContext = () => {
     getSearchSessionId: () => undefined,
     types: {},
     variables: {},
-    abortSignal: {} as any,
-    inspectorAdapters: {} as any,
+    abortSignal: {},
+    inspectorAdapters: {},
   } as ExecutionContext;
 };
diff --git a/src/plugins/expressions/public/loader.test.ts b/src/plugins/expressions/public/loader.test.ts
index ff960f4a3a80..f22963cedf61 100644
--- a/src/plugins/expressions/public/loader.test.ts
+++ b/src/plugins/expressions/public/loader.test.ts
@@ -16,12 +16,14 @@ import {
   IInterpreterRenderHandlers,
   RenderMode,
   AnyExpressionFunctionDefinition,
+  ExpressionsService,
+  ExecutionContract,
 } from '../common';
 
 // eslint-disable-next-line
 const { __getLastExecution, __getLastRenderMode } = require('./services');
 
-const element: HTMLElement = null as any;
+const element = null as unknown as HTMLElement;
 
 let testScheduler: TestScheduler;
 
@@ -36,8 +38,9 @@ jest.mock('./services', () => {
     },
   };
 
-  // eslint-disable-next-line
-  const service = new (require('../common/service/expressions_services').ExpressionsService as any)();
+  const service: ExpressionsService =
+    // eslint-disable-next-line @typescript-eslint/no-var-requires
+    new (require('../common/service/expressions_services').ExpressionsService)();
 
   const testFn: AnyExpressionFunctionDefinition = {
     fn: () => ({ type: 'render', as: 'test' }),
@@ -54,9 +57,9 @@ jest.mock('./services', () => {
 
   service.start();
 
+  let execution: ExecutionContract;
   const moduleMock = {
-    __execution: undefined,
-    __getLastExecution: () => moduleMock.__execution,
+    __getLastExecution: () => execution,
     __getLastRenderMode: () => renderMode,
     getRenderersRegistry: () => ({
       get: (id: string) => renderers[id],
@@ -72,13 +75,14 @@ jest.mock('./services', () => {
   };
 
   const execute = service.execute;
-  service.execute = (...args: any) => {
-    const execution = execute(...args);
+
+  jest.spyOn(service, 'execute').mockImplementation((...args) => {
+    execution = execute(...args);
     jest.spyOn(execution, 'getData');
     jest.spyOn(execution, 'cancel');
-    moduleMock.__execution = execution;
+
     return execution;
-  };
+  });
 
   return moduleMock;
 });
diff --git a/src/plugins/expressions/public/loader.ts b/src/plugins/expressions/public/loader.ts
index 3ab7473d8d73..b0a54e3dec35 100644
--- a/src/plugins/expressions/public/loader.ts
+++ b/src/plugins/expressions/public/loader.ts
@@ -9,7 +9,7 @@
 import { BehaviorSubject, Observable, Subject, Subscription, asyncScheduler, identity } from 'rxjs';
 import { filter, map, delay, throttleTime } from 'rxjs/operators';
 import { defaults } from 'lodash';
-import { UnwrapObservable } from '@kbn/utility-types';
+import { SerializableRecord, UnwrapObservable } from '@kbn/utility-types';
 import { Adapters } from '../../inspector/public';
 import { IExpressionLoaderParams } from './types';
 import { ExpressionAstExpression } from '../common';
@@ -18,7 +18,7 @@ import { ExecutionContract } from '../common/execution/execution_contract';
 import { ExpressionRenderHandler } from './render';
 import { getExpressionsService } from './services';
 
-type Data = any;
+type Data = unknown;
 
 export class ExpressionLoader {
   data$: ReturnType<ExecutionContract['getData']>;
@@ -156,7 +156,7 @@ export class ExpressionLoader {
   };
 
   private render(data: Data): void {
-    this.renderHandler.render(data, this.params.uiState);
+    this.renderHandler.render(data as SerializableRecord, this.params.uiState);
   }
 
   private setParams(params?: IExpressionLoaderParams) {
@@ -169,7 +169,7 @@ export class ExpressionLoader {
         {},
         params.searchContext,
         this.params.searchContext || {}
-      ) as any;
+      );
     }
     if (params.uiState && this.params) {
       this.params.uiState = params.uiState;
diff --git a/src/plugins/expressions/public/react_expression_renderer.test.tsx b/src/plugins/expressions/public/react_expression_renderer.test.tsx
index d31a4c947b09..f1932ce7dd6b 100644
--- a/src/plugins/expressions/public/react_expression_renderer.test.tsx
+++ b/src/plugins/expressions/public/react_expression_renderer.test.tsx
@@ -14,6 +14,7 @@ import { ReactExpressionRenderer } from './react_expression_renderer';
 import { ExpressionLoader } from './loader';
 import { mount } from 'enzyme';
 import { EuiProgress } from '@elastic/eui';
+import { IInterpreterRenderHandlers } from '../common';
 import { RenderErrorHandlerFnType } from './types';
 import { ExpressionRendererEvent } from './render';
 
@@ -234,7 +235,7 @@ describe('ExpressionRenderer', () => {
         done: () => {
           renderSubject.next(1);
         },
-      } as any);
+      } as IInterpreterRenderHandlers);
     });
 
     instance.update();
diff --git a/src/plugins/expressions/public/render.test.ts b/src/plugins/expressions/public/render.test.ts
index 61dc0a25439b..8d4298785572 100644
--- a/src/plugins/expressions/public/render.test.ts
+++ b/src/plugins/expressions/public/render.test.ts
@@ -8,6 +8,7 @@
 
 import { ExpressionRenderHandler, render } from './render';
 import { Observable } from 'rxjs';
+import { SerializableRecord } from '@kbn/utility-types';
 import { ExpressionRenderError } from './types';
 import { getRenderersRegistry } from './services';
 import { first, take, toArray } from 'rxjs/operators';
@@ -79,11 +80,11 @@ describe('ExpressionRenderHandler', () => {
 
     it('in case of error render$ should emit when error renderer is finished', async () => {
       const expressionRenderHandler = new ExpressionRenderHandler(element);
-      expressionRenderHandler.render(false);
+      expressionRenderHandler.render(false as unknown as SerializableRecord);
       const promise1 = expressionRenderHandler.render$.pipe(first()).toPromise();
       await expect(promise1).resolves.toEqual(1);
 
-      expressionRenderHandler.render(false);
+      expressionRenderHandler.render(false as unknown as SerializableRecord);
       const promise2 = expressionRenderHandler.render$.pipe(first()).toPromise();
       await expect(promise2).resolves.toEqual(2);
     });
@@ -92,7 +93,7 @@ describe('ExpressionRenderHandler', () => {
       const expressionRenderHandler = new ExpressionRenderHandler(element, {
         onRenderError: mockMockErrorRenderFunction,
       });
-      await expressionRenderHandler.render(false);
+      await expressionRenderHandler.render(false as unknown as SerializableRecord);
       expect(getHandledError()!.message).toEqual(
         `invalid data provided to the expression renderer`
       );
@@ -122,7 +123,8 @@ describe('ExpressionRenderHandler', () => {
         get: () => ({
           render: (domNode: HTMLElement, config: unknown, handlers: IInterpreterRenderHandlers) => {
             handlers.hasCompatibleActions!({
-              foo: 'bar',
+              name: 'something',
+              data: 'bar',
             });
           },
         }),
@@ -136,7 +138,8 @@ describe('ExpressionRenderHandler', () => {
       await expressionRenderHandler.render({ type: 'render', as: 'something' });
       expect(hasCompatibleActions).toHaveBeenCalledTimes(1);
       expect(hasCompatibleActions.mock.calls[0][0]).toEqual({
-        foo: 'bar',
+        name: 'something',
+        data: 'bar',
       });
     });
 
@@ -156,7 +159,7 @@ describe('ExpressionRenderHandler', () => {
     it('default renderer should use notification service', async () => {
       const expressionRenderHandler = new ExpressionRenderHandler(element);
       const promise1 = expressionRenderHandler.render$.pipe(first()).toPromise();
-      expressionRenderHandler.render(false);
+      expressionRenderHandler.render(false as unknown as SerializableRecord);
       await expect(promise1).resolves.toEqual(1);
       expect(mockNotificationService.toasts.addError).toBeCalledWith(
         expect.objectContaining({
@@ -175,7 +178,7 @@ describe('ExpressionRenderHandler', () => {
       const expressionRenderHandler1 = new ExpressionRenderHandler(element, {
         onRenderError: mockMockErrorRenderFunction,
       });
-      expressionRenderHandler1.render(false);
+      expressionRenderHandler1.render(false as unknown as SerializableRecord);
       const renderPromiseAfterRender = expressionRenderHandler1.render$.pipe(first()).toPromise();
       await expect(renderPromiseAfterRender).resolves.toEqual(1);
       expect(getHandledError()!.message).toEqual(
@@ -188,7 +191,7 @@ describe('ExpressionRenderHandler', () => {
         onRenderError: mockMockErrorRenderFunction,
       });
       const renderPromiseBeforeRender = expressionRenderHandler2.render$.pipe(first()).toPromise();
-      expressionRenderHandler2.render(false);
+      expressionRenderHandler2.render(false as unknown as SerializableRecord);
       await expect(renderPromiseBeforeRender).resolves.toEqual(1);
       expect(getHandledError()!.message).toEqual(
         'invalid data provided to the expression renderer'
@@ -199,9 +202,9 @@ describe('ExpressionRenderHandler', () => {
     // that observables will emit previous result if subscription happens after render
     it('should emit previous render and error results', async () => {
       const expressionRenderHandler = new ExpressionRenderHandler(element);
-      expressionRenderHandler.render(false);
+      expressionRenderHandler.render(false as unknown as SerializableRecord);
       const renderPromise = expressionRenderHandler.render$.pipe(take(2), toArray()).toPromise();
-      expressionRenderHandler.render(false);
+      expressionRenderHandler.render(false as unknown as SerializableRecord);
       await expect(renderPromise).resolves.toEqual([1, 2]);
     });
   });
diff --git a/src/plugins/expressions/public/render.ts b/src/plugins/expressions/public/render.ts
index e9a65d1e8f12..8635a4033bde 100644
--- a/src/plugins/expressions/public/render.ts
+++ b/src/plugins/expressions/public/render.ts
@@ -9,13 +9,20 @@
 import * as Rx from 'rxjs';
 import { Observable } from 'rxjs';
 import { filter } from 'rxjs/operators';
+import { isNumber } from 'lodash';
+import { SerializableRecord } from '@kbn/utility-types';
 import { ExpressionRenderError, RenderErrorHandlerFnType, IExpressionLoaderParams } from './types';
 import { renderErrorHandler as defaultRenderErrorHandler } from './render_error_handler';
-import { IInterpreterRenderHandlers, ExpressionAstExpression, RenderMode } from '../common';
+import {
+  IInterpreterRenderHandlers,
+  IInterpreterRenderEvent,
+  IInterpreterRenderUpdateParams,
+  RenderMode,
+} from '../common';
 
 import { getRenderersRegistry } from './services';
 
-export type IExpressionRendererExtraHandlers = Record<string, any>;
+export type IExpressionRendererExtraHandlers = Record<string, unknown>;
 
 export interface ExpressionRenderHandlerParams {
   onRenderError?: RenderErrorHandlerFnType;
@@ -25,15 +32,10 @@ export interface ExpressionRenderHandlerParams {
   hasCompatibleActions?: (event: ExpressionRendererEvent) => Promise<boolean>;
 }
 
-export interface ExpressionRendererEvent {
-  name: string;
-  data: any;
-}
+// eslint-disable-next-line @typescript-eslint/no-explicit-any
+export type ExpressionRendererEvent = IInterpreterRenderEvent<any>;
 
-interface UpdateValue {
-  newExpression?: string | ExpressionAstExpression;
-  newParams: IExpressionLoaderParams;
-}
+type UpdateValue = IInterpreterRenderUpdateParams<IExpressionLoaderParams>;
 
 export class ExpressionRenderHandler {
   render$: Observable<number>;
@@ -41,7 +43,7 @@ export class ExpressionRenderHandler {
   events$: Observable<ExpressionRendererEvent>;
 
   private element: HTMLElement;
-  private destroyFn?: any;
+  private destroyFn?: Function;
   private renderCount: number = 0;
   private renderSubject: Rx.BehaviorSubject<number | null>;
   private eventsSubject: Rx.Subject<unknown>;
@@ -66,16 +68,14 @@ export class ExpressionRenderHandler {
 
     this.onRenderError = onRenderError || defaultRenderErrorHandler;
 
-    this.renderSubject = new Rx.BehaviorSubject(null as any | null);
-    this.render$ = this.renderSubject
-      .asObservable()
-      .pipe(filter((_) => _ !== null)) as Observable<any>;
+    this.renderSubject = new Rx.BehaviorSubject<number | null>(null);
+    this.render$ = this.renderSubject.asObservable().pipe(filter(isNumber));
 
     this.updateSubject = new Rx.Subject();
     this.update$ = this.updateSubject.asObservable();
 
     this.handlers = {
-      onDestroy: (fn: any) => {
+      onDestroy: (fn: Function) => {
         this.destroyFn = fn;
       },
       done: () => {
@@ -104,14 +104,14 @@ export class ExpressionRenderHandler {
     };
   }
 
-  render = async (value: any, uiState?: any) => {
+  render = async (value: SerializableRecord, uiState?: unknown) => {
     if (!value || typeof value !== 'object') {
       return this.handleRenderError(new Error('invalid data provided to the expression renderer'));
     }
 
     if (value.type !== 'render' || !value.as) {
       if (value.type === 'error') {
-        return this.handleRenderError(value.error);
+        return this.handleRenderError(value.error as unknown as ExpressionRenderError);
       } else {
         return this.handleRenderError(
           new Error('invalid data provided to the expression renderer')
@@ -119,20 +119,20 @@ export class ExpressionRenderHandler {
       }
     }
 
-    if (!getRenderersRegistry().get(value.as)) {
+    if (!getRenderersRegistry().get(value.as as string)) {
       return this.handleRenderError(new Error(`invalid renderer id '${value.as}'`));
     }
 
     try {
       // Rendering is asynchronous, completed by handlers.done()
       await getRenderersRegistry()
-        .get(value.as)!
+        .get(value.as as string)!
         .render(this.element, value.value, {
           ...this.handlers,
           uiState,
-        } as any);
+        });
     } catch (e) {
-      return this.handleRenderError(e);
+      return this.handleRenderError(e as ExpressionRenderError);
     }
   };
 
@@ -156,10 +156,10 @@ export class ExpressionRenderHandler {
 
 export function render(
   element: HTMLElement,
-  data: any,
+  data: unknown,
   options?: ExpressionRenderHandlerParams
 ): ExpressionRenderHandler {
   const handler = new ExpressionRenderHandler(element, options);
-  handler.render(data);
+  handler.render(data as SerializableRecord);
   return handler;
 }
diff --git a/src/plugins/expressions/public/types/index.ts b/src/plugins/expressions/public/types/index.ts
index 172f322f8892..ea47403332c7 100644
--- a/src/plugins/expressions/public/types/index.ts
+++ b/src/plugins/expressions/public/types/index.ts
@@ -36,7 +36,7 @@ export interface ExpressionInterpreter {
 export interface IExpressionLoaderParams {
   searchContext?: SerializableRecord;
   context?: ExpressionValue;
-  variables?: Record<string, any>;
+  variables?: Record<string, unknown>;
   // Enables debug tracking on each expression in the AST
   debug?: boolean;
   disableCaching?: boolean;
diff --git a/src/plugins/vis_type_markdown/public/markdown_fn.test.ts b/src/plugins/vis_type_markdown/public/markdown_fn.test.ts
index bef0b32e392f..148a15fb9fc8 100644
--- a/src/plugins/vis_type_markdown/public/markdown_fn.test.ts
+++ b/src/plugins/vis_type_markdown/public/markdown_fn.test.ts
@@ -8,6 +8,7 @@
 
 import { functionWrapper } from '../../expressions/common/expression_functions/specs/tests/utils';
 import { createMarkdownVisFn } from './markdown_fn';
+import { Arguments } from './types';
 
 describe('interpreter/functions#markdown', () => {
   const fn = functionWrapper(createMarkdownVisFn());
@@ -15,7 +16,7 @@ describe('interpreter/functions#markdown', () => {
     font: { spec: { fontSize: 12 } },
     openLinksInNewTab: true,
     markdown: '## hello _markdown_',
-  };
+  } as unknown as Arguments;
 
   it('returns an object with the correct structure', async () => {
     const actual = await fn(null, args, undefined);
diff --git a/src/plugins/vis_types/metric/public/metric_vis_fn.test.ts b/src/plugins/vis_types/metric/public/metric_vis_fn.test.ts
index 3844c0f21ed0..28124a653629 100644
--- a/src/plugins/vis_types/metric/public/metric_vis_fn.test.ts
+++ b/src/plugins/vis_types/metric/public/metric_vis_fn.test.ts
@@ -10,13 +10,15 @@ import { createMetricVisFn } from './metric_vis_fn';
 import { functionWrapper } from '../../../expressions/common/expression_functions/specs/tests/utils';
 import { Datatable } from '../../../expressions/common/expression_types/specs';
 
+type Arguments = Parameters<ReturnType<typeof createMetricVisFn>['fn']>[1];
+
 describe('interpreter/functions#metric', () => {
   const fn = functionWrapper(createMetricVisFn());
   const context = {
     type: 'datatable',
     rows: [{ 'col-0-1': 0 }],
     columns: [{ id: 'col-0-1', name: 'Count' }],
-  };
+  } as unknown as Datatable;
   const args = {
     percentageMode: false,
     useRanges: false,
@@ -50,7 +52,7 @@ describe('interpreter/functions#metric', () => {
         aggType: 'count',
       },
     ],
-  };
+  } as unknown as Arguments;
 
   it('returns an object with the correct structure', () => {
     const actual = fn(context, args, undefined);
diff --git a/src/plugins/vis_types/pie/public/pie_fn.test.ts b/src/plugins/vis_types/pie/public/pie_fn.test.ts
index d0e0af9807f3..9ba21cdc847e 100644
--- a/src/plugins/vis_types/pie/public/pie_fn.test.ts
+++ b/src/plugins/vis_types/pie/public/pie_fn.test.ts
@@ -8,6 +8,7 @@
 
 import { functionWrapper } from '../../../expressions/common/expression_functions/specs/tests/utils';
 import { createPieVisFn } from './pie_fn';
+import { PieVisConfig } from './types';
 import { Datatable } from '../../../expressions/common/expression_types/specs';
 
 describe('interpreter/functions#pie', () => {
@@ -16,7 +17,7 @@ describe('interpreter/functions#pie', () => {
     type: 'datatable',
     rows: [{ 'col-0-1': 0 }],
     columns: [{ id: 'col-0-1', name: 'Count' }],
-  };
+  } as unknown as Datatable;
   const visConfig = {
     addTooltip: true,
     addLegend: true,
@@ -43,7 +44,7 @@ describe('interpreter/functions#pie', () => {
       params: {},
       aggType: 'count',
     },
-  };
+  } as unknown as PieVisConfig;
 
   beforeEach(() => {
     jest.clearAllMocks();
diff --git a/src/plugins/vis_types/table/public/table_vis_fn.test.ts b/src/plugins/vis_types/table/public/table_vis_fn.test.ts
index 8b08bca16047..d0d9a414bbcc 100644
--- a/src/plugins/vis_types/table/public/table_vis_fn.test.ts
+++ b/src/plugins/vis_types/table/public/table_vis_fn.test.ts
@@ -8,6 +8,7 @@
 
 import { createTableVisFn } from './table_vis_fn';
 import { tableVisResponseHandler } from './utils';
+import { TableVisConfig } from './types';
 
 import { functionWrapper } from '../../../expressions/common/expression_functions/specs/tests/utils';
 import { Datatable } from '../../../expressions/common/expression_types/specs';
@@ -24,7 +25,7 @@ describe('interpreter/functions#table', () => {
     type: 'datatable',
     rows: [{ 'col-0-1': 0 }],
     columns: [{ id: 'col-0-1', name: 'Count' }],
-  };
+  } as unknown as Datatable;
   const visConfig = {
     title: 'My Chart title',
     perPage: 10,
@@ -52,7 +53,7 @@ describe('interpreter/functions#table', () => {
       },
     ],
     buckets: [],
-  };
+  } as unknown as TableVisConfig;
 
   beforeEach(() => {
     jest.clearAllMocks();
diff --git a/src/plugins/vis_types/vislib/public/pie_fn.test.ts b/src/plugins/vis_types/vislib/public/pie_fn.test.ts
index 0df7bf1365be..9c317f9e72dc 100644
--- a/src/plugins/vis_types/vislib/public/pie_fn.test.ts
+++ b/src/plugins/vis_types/vislib/public/pie_fn.test.ts
@@ -6,6 +6,7 @@
  * Side Public License, v 1.
  */
 
+import type { Datatable } from 'src/plugins/expressions';
 import { functionWrapper } from '../../../expressions/common/expression_functions/specs/tests/utils';
 import { createPieVisFn } from './pie_fn';
 // @ts-ignore
@@ -34,7 +35,7 @@ describe('interpreter/functions#pie', () => {
     type: 'datatable',
     rows: [{ 'col-0-1': 0 }],
     columns: [{ id: 'col-0-1', name: 'Count' }],
-  };
+  } as unknown as Datatable;
   const visConfig = {
     type: 'pie',
     addTooltip: true,
diff --git a/x-pack/plugins/canvas/canvas_plugin_src/functions/common/as.ts b/x-pack/plugins/canvas/canvas_plugin_src/functions/common/as.ts
index 4c37d9acc486..63c3f1dcabca 100644
--- a/x-pack/plugins/canvas/canvas_plugin_src/functions/common/as.ts
+++ b/x-pack/plugins/canvas/canvas_plugin_src/functions/common/as.ts
@@ -5,7 +5,12 @@
  * 2.0.
  */
 
-import { Datatable, ExpressionFunctionDefinition, getType } from '../../../types';
+import {
+  Datatable,
+  DatatableColumnType,
+  ExpressionFunctionDefinition,
+  getType,
+} from '../../../types';
 import { getFunctionHelp } from '../../../i18n';
 
 interface Arguments {
@@ -30,14 +35,14 @@ export function asFn(): ExpressionFunctionDefinition<'as', Input, Arguments, Dat
         default: 'value',
       },
     },
-    fn: (input, args) => {
+    fn: (input, args): Datatable => {
       return {
         type: 'datatable',
         columns: [
           {
             id: args.name,
             name: args.name,
-            meta: { type: getType(input) },
+            meta: { type: getType(input) as DatatableColumnType },
           },
         ],
         rows: [
diff --git a/x-pack/plugins/canvas/public/components/function_reference_generator/generate_function_reference.ts b/x-pack/plugins/canvas/public/components/function_reference_generator/generate_function_reference.ts
index 075e65bc24da..289704ae7953 100644
--- a/x-pack/plugins/canvas/public/components/function_reference_generator/generate_function_reference.ts
+++ b/x-pack/plugins/canvas/public/components/function_reference_generator/generate_function_reference.ts
@@ -156,7 +156,7 @@ ${examplesBlock}
 *Returns:* ${output ? wrapInBackTicks(output) : 'Depends on your input and arguments'}\n\n`;
 };
 
-const getArgsTable = (args: { [key: string]: ExpressionFunctionParameter }) => {
+const getArgsTable = (args: { [key: string]: ExpressionFunctionParameter<any> }) => {
   if (!args || Object.keys(args).length === 0) {
     return 'None';
   }
diff --git a/x-pack/plugins/lens/common/expressions/format_column/format_column.test.ts b/x-pack/plugins/lens/common/expressions/format_column/format_column.test.ts
index 28f9b08eff1c..4d53f96c71fd 100644
--- a/x-pack/plugins/lens/common/expressions/format_column/format_column.test.ts
+++ b/x-pack/plugins/lens/common/expressions/format_column/format_column.test.ts
@@ -7,11 +7,10 @@
 
 import { Datatable, DatatableColumn } from 'src/plugins/expressions/public';
 import { functionWrapper } from 'src/plugins/expressions/common/expression_functions/specs/tests/utils';
-import { FormatColumnArgs, formatColumn } from './index';
+import { formatColumn } from './index';
 
 describe('format_column', () => {
-  const fn: (input: Datatable, args: FormatColumnArgs) => Promise<Datatable> =
-    functionWrapper(formatColumn);
+  const fn = functionWrapper(formatColumn);
 
   let datatable: Datatable;