diff --git a/build.rs b/build.rs
index 9fc2367..f7966ef 100644
--- a/build.rs
+++ b/build.rs
@@ -2,4 +2,28 @@ extern crate napi_build;
 
 fn main() {
     napi_build::setup();
+
+    // Expose the npm package version (from package.json) so the client can report
+    // it in its user agent. The Cargo package version is kept at 0.0.0 by napi, so
+    // CARGO_PKG_VERSION is not usable here. The release artifacts are built via
+    // `yarn build` from a checkout whose package.json holds the release version,
+    // so reading it here picks up the real version regardless of the build env.
+    // Falls back to CARGO_PKG_VERSION if package.json can't be read.
+    let version = std::fs::read_to_string("package.json")
+        .ok()
+        .and_then(|pkg| {
+            pkg.lines().find_map(|line| {
+                line.trim()
+                    .strip_prefix("\"version\":")
+                    .map(|rest| {
+                        rest.trim()
+                            .trim_matches(|c| c == ',' || c == '"' || c == ' ')
+                            .to_string()
+                    })
+            })
+        })
+        .unwrap_or_else(|| env!("CARGO_PKG_VERSION").to_string());
+
+    println!("cargo:rustc-env=NPM_PKG_VERSION={version}");
+    println!("cargo:rerun-if-changed=package.json");
 }
diff --git a/src/lib.rs b/src/lib.rs
index 277ea07..73bd014 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -89,7 +89,9 @@ impl HypersyncClient {
     /// Create a new client with given config
     #[napi(constructor)]
     pub fn new(cfg: ClientConfig) -> napi::Result<HypersyncClient> {
-        Self::new_with_agent(cfg, format!("hscn/{}", env!("CARGO_PKG_VERSION")))
+        // NPM_PKG_VERSION is the package.json version, injected by build.rs.
+        // (CARGO_PKG_VERSION is 0.0.0 because napi keeps the Cargo version static.)
+        Self::new_with_agent(cfg, format!("hscn/{}", env!("NPM_PKG_VERSION")))
     }
 
     /// Create a new client with custom user agent