diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index 57546e3..d6c5db1 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -74,6 +74,16 @@ jobs:
           files: coverage/coverage-final.json
           token: ${{ secrets.CODECOV_TOKEN }}
 
+  version:
+    name: Version sync
+    runs-on: ubuntu-latest
+    steps:
+      - *checkout
+      - *setup-node-22
+      - *install
+      - name: Check src/version.ts matches package.json
+        run: npm run check:version
+
   examples:
     name: Examples
     runs-on: ubuntu-latest
@@ -90,7 +100,7 @@ jobs:
   check:
     name: CI check
     if: always()
-    needs: [lint, typecheck, test, examples]
+    needs: [lint, typecheck, test, examples, version]
     runs-on: ubuntu-latest
     steps:
       - uses: re-actors/alls-green@release/v1
diff --git a/package.json b/package.json
index fd09bc4..7cedb3b 100644
--- a/package.json
+++ b/package.json
@@ -18,7 +18,9 @@
   ],
   "scripts": {
     "generate": "rm -rf src/generated && buf generate",
-    "build": "tsc",
+    "gen-version": "node scripts/gen-version.mjs",
+    "check:version": "node scripts/gen-version.mjs --check",
+    "build": "node scripts/gen-version.mjs && tsc",
     "lint": "biome check src/ test/",
     "format": "biome format --write src/ test/",
     "typecheck": "tsc --noEmit",
diff --git a/scripts/gen-version.mjs b/scripts/gen-version.mjs
new file mode 100644
index 0000000..f270574
--- /dev/null
+++ b/scripts/gen-version.mjs
@@ -0,0 +1,28 @@
+#!/usr/bin/env node
+// Generates src/version.ts from package.json.
+// With --check: exits non-zero if the file is out of sync.
+import { readFileSync, writeFileSync } from "node:fs";
+
+const pkg = JSON.parse(readFileSync("package.json", "utf8"));
+const version = pkg.version;
+
+const content =
+	`// Generated by scripts/gen-version.mjs — do not edit manually.\n` +
+	`export const VERSION = "${version}";\n`;
+
+if (process.argv.includes("--check")) {
+	const existing = readFileSync("src/version.ts", "utf8");
+	if (existing !== content) {
+		const match = existing.match(/VERSION = "([^"]+)"/);
+		console.error(
+			`src/version.ts is out of sync with package.json\n` +
+				`  package.json : ${version}\n` +
+				`  src/version.ts: ${match?.[1] ?? "(unreadable)"}`,
+		);
+		process.exit(1);
+	}
+	console.log(`src/version.ts is in sync with package.json (${version})`);
+} else {
+	writeFileSync("src/version.ts", content);
+	console.log(`Generated src/version.ts with VERSION = "${version}"`);
+}
diff --git a/src/index.ts b/src/index.ts
index aa26770..80c7158 100644
--- a/src/index.ts
+++ b/src/index.ts
@@ -4,7 +4,7 @@
  * @packageDocumentation
  */
 
-export const VERSION = "0.2.0-alpha.1";
+export { VERSION } from "./version.js";
 export const SUPPORTED_SERVER_VERSION = ">=0.8.0,<1.0.0";
 export const PROTO_VERSION = "v1";
 
diff --git a/src/version.ts b/src/version.ts
new file mode 100644
index 0000000..83f1e5e
--- /dev/null
+++ b/src/version.ts
@@ -0,0 +1,2 @@
+// Generated by scripts/gen-version.mjs — do not edit manually.
+export const VERSION = "0.3.0-alpha.1";
diff --git a/test/version.test.ts b/test/version.test.ts
index e601acc..1dad747 100644
--- a/test/version.test.ts
+++ b/test/version.test.ts
@@ -1,9 +1,13 @@
+import { createRequire } from "node:module";
 import { describe, expect, it } from "vitest";
 import { PROTO_VERSION, SUPPORTED_SERVER_VERSION, VERSION } from "../src/index.js";
 
+const require = createRequire(import.meta.url);
+const pkg = require("../package.json") as { version: string };
+
 describe("version constants", () => {
-	it("exports SDK version", () => {
-		expect(VERSION).toBe("0.2.0-alpha.1");
+	it("exports SDK version matching package.json", () => {
+		expect(VERSION).toBe(pkg.version);
 	});
 
 	it("exports supported server version range", () => {