# init(options) Initializes MapKit JS by providing an authorization callback function and optional language. ``` init(options: MapKitInitializationOptions): void; ``` ## Parameters `options` MapKit JS initialization options. ## Discussion Unless you wish to explicitly control initialization timing in JavaScript, use `data-token` instead of this method. See [Loading the latest version of MapKit JS](/documentation/MapKitJS/loading-the-latest-version-of-mapkit-js) for more information. If you’re using this method, provide the token by setting [`authorizationCallback`](/documentation/MapKitJS/MapKitInitializationOptions/authorizationCallback) on a JavaScript object as a function. The [`authorizationCallback`](/documentation/MapKitJS/MapKitInitializationOptions/authorizationCallback) function calls `done()` to return the token. [Creating a Maps token](/documentation/MapKitJS/creating-a-maps-token) shows how to create Maps tokens. When you create a server endpoint to deliver new tokens to MapKit JS, make an asynchronous request to this endpoint in your [`authorizationCallback`](/documentation/MapKitJS/MapKitInitializationOptions/authorizationCallback) function and call `done()` with the result. The following example shows creating a callback that requests a token from a server endpoint and sets a preferred language for the map: ```javascript mapkit.init({ authorizationCallback: function(done) { fetch("/gettoken") .then(res => res.text()) .then(done); }, language: "es" }); ``` If you don’t set up a server endpoint, you can alternatively set [`authorizationCallback`](/documentation/MapKitJS/MapKitInitializationOptions/authorizationCallback) to a function that provides a pregenerated token string. ```javascript mapkit.init({ authorizationCallback: function(done) { done("your-token-string"); }, language: "es" }); ``` An instance of [`mapkit`](/documentation/MapKitJS/mapkit) emits a `configuration-change` event after MapKit JS initializes, and an `error` event when initialization fails. You can learn more about both of these events in [Handling initialization events](/documentation/MapKitJS/handling-initialization-events). --- Copyright © 2026 Apple Inc. All rights reserved. | [Terms of Use](https://www.apple.com/legal/internet-services/terms/site.html) | [Privacy Policy](https://www.apple.com/privacy/privacy-policy)