diff --git a/x-pack/plugins/actions/server/builtin_action_types/webhook.test.ts b/x-pack/plugins/actions/server/builtin_action_types/webhook.test.ts
index 6daf15208f4d..53b17f58d6e1 100644
--- a/x-pack/plugins/actions/server/builtin_action_types/webhook.test.ts
+++ b/x-pack/plugins/actions/server/builtin_action_types/webhook.test.ts
@@ -114,6 +114,17 @@ describe('config validation', () => {
     });
   });
 
+  test('config validation failed when a url is invalid', () => {
+    const config: Record<string, string> = {
+      url: 'example.com/do-something',
+    };
+    expect(() => {
+      validateConfig(actionType, config);
+    }).toThrowErrorMatchingInlineSnapshot(
+      '"error validating action type config: error configuring webhook action: unable to parse url: TypeError: Invalid URL: example.com/do-something"'
+    );
+  });
+
   test('config validation passes when valid headers are provided', () => {
     // any for testing
     // eslint-disable-next-line @typescript-eslint/no-explicit-any
diff --git a/x-pack/plugins/actions/server/builtin_action_types/webhook.ts b/x-pack/plugins/actions/server/builtin_action_types/webhook.ts
index 4a34fea76216..0b8b27b27892 100644
--- a/x-pack/plugins/actions/server/builtin_action_types/webhook.ts
+++ b/x-pack/plugins/actions/server/builtin_action_types/webhook.ts
@@ -85,8 +85,20 @@ function validateActionTypeConfig(
   configurationUtilities: ActionsConfigurationUtilities,
   configObject: ActionTypeConfigType
 ) {
+  let url: URL;
   try {
-    configurationUtilities.ensureWhitelistedUri(configObject.url);
+    url = new URL(configObject.url);
+  } catch (err) {
+    return i18n.translate('xpack.actions.builtin.webhook.webhookConfigurationErrorNoHostname', {
+      defaultMessage: 'error configuring webhook action: unable to parse url: {err}',
+      values: {
+        err,
+      },
+    });
+  }
+
+  try {
+    configurationUtilities.ensureWhitelistedUri(url.toString());
   } catch (whitelistError) {
     return i18n.translate('xpack.actions.builtin.webhook.webhookConfigurationError', {
       defaultMessage: 'error configuring webhook action: {message}',
diff --git a/x-pack/plugins/triggers_actions_ui/public/application/components/builtin_action_types/webhook/webhook.test.tsx b/x-pack/plugins/triggers_actions_ui/public/application/components/builtin_action_types/webhook/webhook.test.tsx
index 3413465d70d9..337c1f0f18a9 100644
--- a/x-pack/plugins/triggers_actions_ui/public/application/components/builtin_action_types/webhook/webhook.test.tsx
+++ b/x-pack/plugins/triggers_actions_ui/public/application/components/builtin_action_types/webhook/webhook.test.tsx
@@ -40,7 +40,7 @@ describe('webhook connector validation', () => {
       isPreconfigured: false,
       config: {
         method: 'PUT',
-        url: 'http:\\test',
+        url: 'http://test.com',
         headers: { 'content-type': 'text' },
       },
     } as WebhookActionConnector;
@@ -77,6 +77,31 @@ describe('webhook connector validation', () => {
       },
     });
   });
+
+  test('connector validation fails when url in config is not valid', () => {
+    const actionConnector = {
+      secrets: {
+        user: 'user',
+        password: 'pass',
+      },
+      id: 'test',
+      actionTypeId: '.webhook',
+      name: 'webhook',
+      config: {
+        method: 'PUT',
+        url: 'invalid.url',
+      },
+    } as WebhookActionConnector;
+
+    expect(actionTypeModel.validateConnector(actionConnector)).toEqual({
+      errors: {
+        url: ['URL is invalid.'],
+        method: [],
+        user: [],
+        password: [],
+      },
+    });
+  });
 });
 
 describe('webhook action params validation', () => {
diff --git a/x-pack/plugins/triggers_actions_ui/public/application/components/builtin_action_types/webhook/webhook.tsx b/x-pack/plugins/triggers_actions_ui/public/application/components/builtin_action_types/webhook/webhook.tsx
index 9f33e4491233..2c51b21d7003 100644
--- a/x-pack/plugins/triggers_actions_ui/public/application/components/builtin_action_types/webhook/webhook.tsx
+++ b/x-pack/plugins/triggers_actions_ui/public/application/components/builtin_action_types/webhook/webhook.tsx
@@ -7,6 +7,7 @@ import { lazy } from 'react';
 import { i18n } from '@kbn/i18n';
 import { ActionTypeModel, ValidationResult } from '../../../../types';
 import { WebhookActionParams, WebhookActionConnector } from '../types';
+import { isValidUrl } from '../../../lib/value_validators';
 
 export function getActionType(): ActionTypeModel<WebhookActionConnector, WebhookActionParams> {
   return {
@@ -43,6 +44,17 @@ export function getActionType(): ActionTypeModel<WebhookActionConnector, Webhook
           )
         );
       }
+      if (action.config.url && !isValidUrl(action.config.url)) {
+        errors.url = [
+          ...errors.url,
+          i18n.translate(
+            'xpack.triggersActionsUI.components.builtinActionTypes.webhookAction.error.invalidUrlTextField',
+            {
+              defaultMessage: 'URL is invalid.',
+            }
+          ),
+        ];
+      }
       if (!action.config.method) {
         errors.method.push(
           i18n.translate(
diff --git a/x-pack/plugins/triggers_actions_ui/public/application/components/builtin_action_types/webhook/webhook_connectors.tsx b/x-pack/plugins/triggers_actions_ui/public/application/components/builtin_action_types/webhook/webhook_connectors.tsx
index 5cea7d087f33..57c88607c088 100644
--- a/x-pack/plugins/triggers_actions_ui/public/application/components/builtin_action_types/webhook/webhook_connectors.tsx
+++ b/x-pack/plugins/triggers_actions_ui/public/application/components/builtin_action_types/webhook/webhook_connectors.tsx
@@ -246,6 +246,7 @@ const WebhookActionConnectorFields: React.FunctionComponent<ActionConnectorField
               isInvalid={errors.url.length > 0 && url !== undefined}
               fullWidth
               value={url || ''}
+              placeholder="https://<site-url> or http://<site-url>"
               data-test-subj="webhookUrlText"
               onChange={(e) => {
                 editActionConfig('url', e.target.value);