The Unleash front-end API was released in Unleash 4.18. You can read more in the [Unleash 4.18 release blog post](https://www.getunleash.io/blog/new-features-direct-client-side-front-end-api-access-sync-user-groups-and-clone-environments).
The **Unleash front-end API** offers a simplified workflow for connecting a client-side (front-end) applications to Unleash. It provides the exact same API as [Unleash edge](https://docs.getunleash.io/reference/unleash-edge) and the [Unleash proxy - deprecated](../generated/unleash-proxy.md). The front-end API is a quick and easy way to add Unleash to single-page applications and mobile apps.
- **You don't need to configure and run Unleash Edge.** The front-end API is part of Unleash itself and not an external process. All clients will work exactly the same as they would with Unleash Edge.
- **It can't handle a large number of requests per second.** Because the front-end API is part of Unleash, you can't scale it horizontally the way you can scale Unleash Edge.
- **It sends client details to your Unleash instance.** Unleash only stores these details in its short-term runtime cache, but this can be a privacy issue for some use cases.
These points make the Unleash front-end API best suited for development purposes and applications that don’t receive a lot of traffic, such as internal dashboards. However, because the API is identical to the Unleash Edge API, you can go from one to the other at any time. As such, you can start out by using the front-end API and switch to using Unleash Edge when you need it.
As a client-side API, you should use a [front-end API token](../reference/api-tokens-and-client-keys.mdx#front-end-tokens) to interact with it. Refer to the [how to create API tokens](../how-to/how-to-create-api-tokens.mdx) guide for steps on how to create API tokens.
You need to allow traffic from your application domains to use the Unleash front-end API with web and hybrid mobile applications. You can update the front-end API CORS settings from the Unleash UI under _admin \> CORS_ or by using the API.
### API URL
The client needs to point to the correct API endpoint. The front-end API is available at `<your-unleash-instance>/api/frontend`.
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You can create appropriate token, with type `FRONTEND` on `<YOUR_UNLEASH_URL>/api/admin/create-token` page or with a request to `/api/admin/api-tokens`. See our guide on [how to create API tokens](../how-to/how-to-create-api-tokens.mdx) for more details.
Internally, Unleash creates a new Unleash client for each token it receives. Each client is configured with the project and environment specified in the token.
Each client updates its feature flag configuration at a specified refresh interval plus a random offset between 0 and 10 seconds. By default, the refresh interval is set to 10 seconds. The random offset is used to stagger incoming requests to avoid a large number of clients all querying the database simultaneously. A new, random offset is used for every update.
The refresh interval is specified in milliseconds and can be set by using the `FRONTEND_API_REFRESH_INTERVAL_MS` environment variable or by using the `frontendApi.refreshIntervalInMs` configuration option in code.
