diff --git a/crates/model/Cargo.toml b/crates/model/Cargo.toml
index 922f3ac..2ef71f2 100644
--- a/crates/model/Cargo.toml
+++ b/crates/model/Cargo.toml
@@ -6,4 +6,5 @@ edition = "2018"
 [dependencies]
 serde = { version = "1.0", features = ["derive"] }
 serde_json = "1.0"
-url = {version = "2.2.2", features = ["serde"]}
\ No newline at end of file
+url = {version = "2.2.2", features = ["serde"]}
+addonscript-versioning = { path = "../versioning" }
\ No newline at end of file
diff --git a/crates/model/src/lib.rs b/crates/model/src/lib.rs
index f4a3a55..3fd3a85 100644
--- a/crates/model/src/lib.rs
+++ b/crates/model/src/lib.rs
@@ -1,5 +1,6 @@
 use std::collections::HashSet;
 
+use addonscript_versioning::{Version, VersionRestriction};
 use serde::{Deserialize, Serialize};
 
 pub use self::{
@@ -16,7 +17,7 @@ pub struct Manifest {
     pub addonscript: AddonScript,
     pub id: String,
     pub namespace: String,
-    pub version: String,
+    pub version: Version,
     #[serde(skip_serializing_if = "Option::is_none")]
     pub files: Option<Vec<File>>,
     #[serde(skip_serializing_if = "Option::is_none")]
@@ -62,7 +63,7 @@ pub struct Relation {
     pub id: String,
     #[serde(skip_serializing_if = "Option::is_none")]
     pub namespace: Option<String>,
-    pub version: String,
+    pub version: VersionRestriction,
     #[serde(skip_serializing_if = "Option::is_none")]
     pub repositories: Option<Vec<String>>,
     #[serde(skip_serializing_if = "Option::is_none")]
diff --git a/crates/versioning/Cargo.toml b/crates/versioning/Cargo.toml
index 3222b55..232064d 100644
--- a/crates/versioning/Cargo.toml
+++ b/crates/versioning/Cargo.toml
@@ -4,4 +4,6 @@ version = "0.1.0"
 edition = "2018"
 
 [dependencies]
-thiserror = "1.0.24"
\ No newline at end of file
+thiserror = "1.0.24"
+semver = "1.0"
+serde = "1.0"
\ No newline at end of file
diff --git a/crates/versioning/src/errors.rs b/crates/versioning/src/errors.rs
index 02b08c6..d958b3e 100644
--- a/crates/versioning/src/errors.rs
+++ b/crates/versioning/src/errors.rs
@@ -11,5 +11,9 @@ pub enum Error {
     IllegalVersionRange,
     #[error("Version range overlap")]
     RangeOverlap,
+    #[error("Version contains invalid characters")]
+    InvalidVersion,
+    #[error("SemVer error: {0}")]
+    Semver(#[from] semver::Error),
 }
 pub type Result<T> = std::result::Result<T, Error>;
diff --git a/crates/versioning/src/lib.rs b/crates/versioning/src/lib.rs
index b7209e2..222508a 100644
--- a/crates/versioning/src/lib.rs
+++ b/crates/versioning/src/lib.rs
@@ -1,6 +1,10 @@
 pub mod errors;
 pub mod maven;
+mod serde;
 mod util;
+pub mod version;
+
+pub use version::{Version, VersionRestriction};
 
 #[cfg(test)]
 mod tests {
diff --git a/crates/versioning/src/maven/restriction.rs b/crates/versioning/src/maven/restriction.rs
index 1fb30d0..123df14 100644
--- a/crates/versioning/src/maven/restriction.rs
+++ b/crates/versioning/src/maven/restriction.rs
@@ -4,12 +4,12 @@ use crate::{
 };
 
 use super::version::{ComparableVersion, VersionOption};
-#[derive(Debug)]
+#[derive(Debug, Clone)]
 pub struct VersionRange {
     pub(crate) restrictions: Vec<Restriction>,
     pub(crate) recommended_version: Option<ComparableVersion>,
 }
-#[derive(Debug)]
+#[derive(Debug, Clone)]
 pub struct Restriction {
     pub lower_bound: Option<ComparableVersion>,
     pub lower_bound_inclusive: bool,
diff --git a/crates/versioning/src/serde.rs b/crates/versioning/src/serde.rs
new file mode 100644
index 0000000..6f0eead
--- /dev/null
+++ b/crates/versioning/src/serde.rs
@@ -0,0 +1,68 @@
+use ::serde::{Deserialize, Deserializer, Serialize};
+use serde::de::Visitor;
+
+use crate::{Version, VersionRestriction};
+
+impl Serialize for Version {
+    fn serialize<S>(&self, serializer: S) -> Result<S::Ok, S::Error>
+    where
+        S: serde::Serializer,
+    {
+        serializer.serialize_str(&self.to_string())
+    }
+}
+
+impl Serialize for VersionRestriction {
+    fn serialize<S>(&self, serializer: S) -> Result<S::Ok, S::Error>
+    where
+        S: serde::Serializer,
+    {
+        serializer.serialize_str(&self.to_string())
+    }
+}
+
+impl<'de> Deserialize<'de> for Version {
+    fn deserialize<D>(deserializer: D) -> Result<Self, D::Error>
+    where
+        D: Deserializer<'de>,
+    {
+        struct Vis;
+        impl<'de> Visitor<'de> for Vis {
+            type Value = Version;
+            fn expecting(&self, formatter: &mut std::fmt::Formatter) -> std::fmt::Result {
+                formatter.write_str("an AddonScript version")
+            }
+            fn visit_str<E>(self, v: &str) -> Result<Self::Value, E>
+            where
+                E: serde::de::Error,
+            {
+                v.parse::<Version>()
+                    .map_err(|e| E::custom(format!("invalid version: {}", e)))
+            }
+        }
+        deserializer.deserialize_str(Vis)
+    }
+}
+
+impl<'de> Deserialize<'de> for VersionRestriction {
+    fn deserialize<D>(deserializer: D) -> Result<Self, D::Error>
+    where
+        D: Deserializer<'de>,
+    {
+        struct Vis;
+        impl<'de> Visitor<'de> for Vis {
+            type Value = VersionRestriction;
+            fn expecting(&self, formatter: &mut std::fmt::Formatter) -> std::fmt::Result {
+                formatter.write_str("an AddonScript version restriction")
+            }
+            fn visit_str<E>(self, v: &str) -> Result<Self::Value, E>
+            where
+                E: serde::de::Error,
+            {
+                v.parse::<VersionRestriction>()
+                    .map_err(|e| E::custom(format!("invalid version restriction: {}", e)))
+            }
+        }
+        deserializer.deserialize_str(Vis)
+    }
+}
diff --git a/crates/versioning/src/version.rs b/crates/versioning/src/version.rs
new file mode 100644
index 0000000..64e7719
--- /dev/null
+++ b/crates/versioning/src/version.rs
@@ -0,0 +1,141 @@
+use std::str::FromStr;
+
+use semver::VersionReq;
+
+use crate::{
+    errors::Error,
+    maven::{restriction::VersionRange, version::ComparableVersion},
+};
+
+#[derive(Clone, Eq, Debug)]
+pub struct Version {
+    raw: String,
+    maven: ComparableVersion,
+    semver: Option<semver::Version>,
+}
+
+#[derive(Clone, Debug)]
+pub struct VersionRestriction {
+    raw: String,
+    exact: Option<Version>,
+    restriction: VersionRestrictionInner,
+}
+
+#[derive(Clone, Debug)]
+enum VersionRestrictionInner {
+    Semver(VersionReq),
+    Maven(VersionRange),
+}
+
+impl VersionRestriction {
+    pub fn parse(raw: String) -> Result<Self, Error> {
+        if !raw.is_ascii() {
+            return Err(Error::IllegalVersionRange);
+        }
+        let trimmed = raw.trim().to_string();
+        let is_semver =
+            trimmed.starts_with('=') || trimmed.starts_with('<') || trimmed.starts_with('>');
+        let mut exact: Option<Version> = None;
+
+        let inner = if is_semver {
+            let semver = VersionReq::parse(trimmed.as_str())?;
+            VersionRestrictionInner::Semver(semver)
+        } else {
+            let maven = VersionRange::parse(trimmed)?;
+            if maven.restrictions.is_empty() {
+                let recomm = maven.get_recommended().ok_or(Error::IllegalVersionRange)?;
+                exact = Some(Version::parse(recomm.to_string())?);
+            }
+
+            VersionRestrictionInner::Maven(maven)
+        };
+        Ok(VersionRestriction {
+            raw,
+            exact,
+            restriction: inner,
+        })
+    }
+
+    pub fn contains_version(&self, version: &Version) -> bool {
+        match &self.restriction {
+            VersionRestrictionInner::Semver(semver) => {
+                if let Some(sv) = &version.semver {
+                    semver.matches(sv)
+                } else {
+                    false
+                }
+            }
+            VersionRestrictionInner::Maven(maven) => maven.contains_version(&version.maven),
+        }
+    }
+
+    pub fn is_exact_version(&self) -> bool {
+        self.exact.is_some()
+    }
+
+    pub fn get_exact_version(&self) -> Option<Version> {
+        self.exact.clone()
+    }
+}
+
+impl FromStr for VersionRestriction {
+    type Err = Error;
+
+    fn from_str(s: &str) -> Result<Self, Self::Err> {
+        Self::parse(s.to_string())
+    }
+}
+
+impl ToString for VersionRestriction {
+    fn to_string(&self) -> String {
+        self.raw.clone()
+    }
+}
+
+impl PartialEq for Version {
+    fn eq(&self, other: &Self) -> bool {
+        self.maven == other.maven
+    }
+}
+
+impl PartialOrd for Version {
+    fn partial_cmp(&self, other: &Self) -> Option<std::cmp::Ordering> {
+        self.maven.partial_cmp(&other.maven)
+    }
+}
+
+impl Ord for Version {
+    fn cmp(&self, other: &Self) -> std::cmp::Ordering {
+        self.maven.cmp(&other.maven)
+    }
+}
+
+impl Version {
+    pub fn parse(raw: String) -> Result<Self, Error> {
+        if raw.contains(char::is_whitespace) || !raw.is_ascii() {
+            return Err(Error::InvalidVersion);
+        }
+        let maven = ComparableVersion::parse(raw.clone())?;
+        let semver = semver::Version::parse(raw.as_str()).ok();
+
+        Ok(Self { raw, maven, semver })
+    }
+
+    pub fn is_semver(&self) -> bool {
+        self.semver.is_some()
+    }
+}
+
+impl FromStr for Version {
+    type Err = Error;
+
+    fn from_str(s: &str) -> Result<Self, Self::Err> {
+        Self::parse(s.to_string())
+    }
+}
+
+impl ToString for Version {
+    fn to_string(&self) -> String {
+        self.raw.clone()
+    }
+}