> ## Documentation Index
> Fetch the complete documentation index at: https://developers.kit.com/llms.txt
> Use this file to discover all available pages before exploring further.

# API V5 overview

> What V5's unstable status means for your integration, and how V5 works alongside V4

> [!WARNING]
>
> API V5 is unstable. Its endpoints can change in breaking ways, or be removed, without a deprecation period. Use [API V4](https://developers.kit.com/api-reference/overview.md) for integrations that need a stable contract.

API V5 is where new endpoints, and new versions of existing ones, take shape before they're stable. All API calls are relative to the base URL `https://api.kit.com/v5/`.

## What unstable means

* A V5 endpoint can change in a breaking way, or be removed, without a deprecation period.
* Every change to a documented V5 endpoint is in the [changelog](https://developers.kit.com/changelog.md) under the **API V5** tag, so check it before you update a client. The changelog also has an RSS feed.
* When a V5 endpoint is ready for stable use, we'll announce it in the changelog.

## How V5 relates to V4

V5 only has endpoints that are new or that change how a V4 endpoint works. Everything else stays on V4, so an integration that uses V5 will usually call V4 too, and mixing the two versions is expected.

A V5 endpoint doesn't change its V4 counterpart: V4 keeps its existing behavior.

## What V5 shares with V4

* **Authentication:** the same [API keys and OAuth access tokens](https://developers.kit.com/api-reference/authentication.md) work for both versions. There are no separate V5 credentials or OAuth flow.
* **Rate limits:** V4 and V5 requests count against the same [rate limit](https://developers.kit.com/api-reference/response-codes.md) for each access token or API key.
* **Errors:** errors use the same `errors` array and the same [status codes](https://developers.kit.com/api-reference/response-codes.md).
* **Pagination:** list endpoints use the same [cursor-based pagination](https://developers.kit.com/api-reference/pagination.md).

## Telling V5 responses apart

V5 responses carry an `X-Kit-API-Stability: unstable` header, including authentication, validation and rate-limit errors. A client or an AI agent that never reads these docs can still tell it's talking to an unstable version. V4 responses don't carry the header.

## Feedback

We'd like to hear how V5 works for you, and what you'd change before an endpoint is stable. Join the [Developer Community](https://kit.typeform.com/to/f8urvmPe) to tell us.


## Related topics

- [Changelog](https://developers.kit.com/changelog.md)
- [Kit App Store overview](https://developers.kit.com/kit-app-store/overview.md)
- [Plugin overview](https://developers.kit.com/plugins/overview.md)
- [MCP overview](https://developers.kit.com/mcp/overview.md)
- [Overview](https://developers.kit.com/plugins/component-library/overview.md)


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