# API Reference

While accessing Clerk functionality via SDK is the easiest path, Clerk offers two different HTTP APIs for you to interact with directly.

[The Clerk Frontend API](https://clerk.com/docs/reference/frontend-api){{ target: '_blank' }} is meant to be accessed from a browser or native clients. This is what the Clerk SDK's utilize. Use this API if you are building client-side functionality.

[The Clerk Backend API](https://clerk.com/docs/reference/backend-api){{ target: '_blank' }} is meant to be accessed by backend servers. Use this API if you need to update data inside of Clerk's systems outside the concept of a session, like coordinating data sync operations with third-parties or fetching and updating configuration settings.

[The Clerk Platform API](https://clerk.com/docs/reference/platform-api){{ target: '_blank' }} is meant to be accessed by backend servers. Use this API if you need to manage resources of a workspace such as your Clerk applications, domains, and application transfers.

For more information about how Clerk works, see the [dedicated guide](https://clerk.com/docs/guides/how-clerk-works/overview.md).

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## Sitemap

[Overview of all docs pages](https://clerk.com/docs/llms.txt)