diff --git a/gluon.d.ts b/gluon.d.ts
new file mode 100644
index 0000000..24b3313
--- /dev/null
+++ b/gluon.d.ts
@@ -0,0 +1,22 @@
+/** A browser that Gluon supports. */
+type Browser = 'chrome'|'chrome_canary'|'chromium'|'edge'|'firefox'|'firefox_nightly';
+
+/** Additional options for opening */
+type OpenOptions = {
+  /** Function to evaluate in the web context once loaded. */
+  onLoad?: function,
+
+  /** Force Gluon to use a browser instead of automatically finding. */
+  forceBrowser?: Browser,
+};
+
+/**
+ * Open a new Gluon window.
+ */
+export function open(
+  /** URL to load in the window. */
+  url: string,
+
+  /** Additional options for opening. */
+  options: OpenOptions
+);
\ No newline at end of file
diff --git a/package.json b/package.json
index 0f483ca..b7d1b2f 100644
--- a/package.json
+++ b/package.json
@@ -3,6 +3,7 @@
   "version": "0.6.0",
   "description": "Make websites into desktop apps with system installed browsers and NodeJS.",
   "main": "src/index.js",
+  "types": "gluon.d.ts",
   "scripts": {},
   "repository": {
     "type": "git",
diff --git a/src/index.js b/src/index.js
index 6a516a3..88d6f73 100644
--- a/src/index.js
+++ b/src/index.js
@@ -13,10 +13,6 @@ import Firefox from './browser/firefox.js';
 const __filename = fileURLToPath(import.meta.url);
 const __dirname = dirname(__filename);
 
-/**
- * @typedef {'chrome'|'chrome_canary'|'chromium'|'edge'|'firefox'|'firefox_nightly'} Browser
- */
-
 const browserPaths = ({
   win32: process.platform === 'win32' && {
     chrome: join(process.env.PROGRAMFILES, 'Google', 'Chrome', 'Application', 'chrome.exe'),
@@ -108,15 +104,6 @@ const startBrowser = async (url, { windowSize, forceBrowser }) => {
   });
 };
 
-/**
- * Open a new Gluon window.
- *
- * @param {string} url - URL to load in the browser.
- * @param {Object} options - Optional further options.
- * @param {Function} [options.onLoad] - This function is evaluated in the web context once loaded.
- * @param {Browser} [options.forceBrowser] - Force window to use a certain browser.
- * @returns {any} - Instance of a Gluon window.
- */
 export const open = async (url, { windowSize, onLoad, forceBrowser } = {}) => {
   log('starting browser...');