diff --git a/tracker/index.d.ts b/tracker/index.d.ts
new file mode 100644
index 00000000..67cebc08
--- /dev/null
+++ b/tracker/index.d.ts
@@ -0,0 +1,138 @@
+type TrackedProperties = {
+  /**
+   * Hostname of server
+   *
+   * @description extracted from `window.location.hostname`
+   * @example 'analytics.umami.is'
+   */
+  hostname: string;
+
+  /**
+   * Browser language
+   *
+   * @description extracted from `window.navigator.language`
+   * @example 'en-US', 'fr-FR'
+   */
+  language: string;
+
+  /**
+   * Page referrer
+   *
+   * @description extracted from `window.navigator.language`
+   * @example 'https://analytics.umami.is/docs/getting-started'
+   */
+  referrer: string;
+
+  /**
+   * Screen dimensions
+   *
+   * @description extracted from `window.screen.width` and `window.screen.height`
+   * @example '1920x1080', '2560x1440'
+   */
+  screen: string;
+
+  /**
+   * Page title
+   *
+   * @description extracted from `document.querySelector('head > title')`
+   * @example 'umami'
+   */
+  title: string;
+
+  /**
+   * Page url
+   *
+   * @description built from `${window.location.pathname}${window.location.search}`
+   * @example 'docs/getting-started'
+   */
+  url: string;
+
+  /**
+   * Website ID (required)
+   *
+   * @example 'b59e9c65-ae32-47f1-8400-119fcf4861c4'
+   */
+  website: string;
+};
+
+type WithRequired<T, K extends keyof T> = T & { [P in K]-?: T[P] }
+
+/**
+ *
+ * Event Data can work with any JSON data. There are a few rules in place to maintain performance.
+ * - Numbers have a max precision of 4.
+ * - Strings have a max length of 500.
+ * - Arrays are converted to a String, with the same max length of 500.
+ * - Objects have a max of 50 properties. Arrays are considered 1 property.
+ */
+type EventData = Record<string, object>;
+type EventProperties = {
+  name: string;
+  data?: EventData;
+} & WithRequired<TrackedProperties, 'website'>
+| WithRequired<TrackedProperties, 'website'>;
+
+interface Window {
+  umami: {
+    track: {
+      /**
+       * Track a page view
+       *
+       * @example ```
+       * umami.track();
+       * ```
+       */
+      (): Promise<string>;
+
+      /**
+       * Track an event with a given name
+       *
+       * @example ```
+       * umami.track('signup-button');
+       * ```
+       */
+      (eventName: string): Promise<string>;
+
+      /**
+       * Tracks an event with dynamic data.
+       *
+       * When tracking events, the default properties are included in the payload. This is equivalent to running:
+       *
+       * ```js
+       * umami.track(props => ({
+       *   ...props,
+       *   name: 'signup-button',
+       *   data: {
+       *     name: 'newsletter',
+       *     id: 123
+       *   }
+       * }));
+       * ```
+       *
+       * @example ```
+       * umami.track('signup-button', { name: 'newsletter', id: 123 });
+       * ```
+       */
+      (eventName: string, obj: EventData): Promise<string>;
+
+      /**
+       * Tracks a page view with custom properties
+       *
+       * @example ```
+       * umami.track({ website: 'e676c9b4-11e4-4ef1-a4d7-87001773e9f2', url: '/home', title: 'Home page' });
+       * ```
+       */
+      (properties: WithRequired<Partial<TrackedProperties>, 'website'>): Promise<string>;
+
+      /**
+       * Tracks an event with fully customizable dynamic data
+       * Ilf you don't specify any `name` and/or `data`, it will be treated as a page view
+       *
+       * @example ```
+       * umami.track((props) => ({ ...props, url: path }));
+       * ```
+       */
+      (eventFunction: (prop: TrackedProperties) => EventProperties): Promise<string>;
+    };
+  };
+}