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

# Explore the API

> Browse endpoints and try requests against the Flow API.

Use the resource groups below to find an endpoint. Each endpoint page describes its parameters, request body, and responses, with generated code examples and an interactive playground.

The playground uses `https://backend.branch.flowengineering.com`. Enter your personal API key and the required `customer` header, then supply any project or entity IDs. Start with a GET request to verify access.

<Warning>
  The playground makes live requests using your permissions. Write operations change live data. Use a test project and branch when trying writes.
</Warning>

The reference covers Flow's customer-facing API. For setup, see [Authentication](/api/authentication) and [Workspace identifier](/api/authentication#workspace-identifier). For pagination and retry behavior, see [API conventions](/api/conventions).

[Download the OpenAPI specification](/openapi/customer-api.json). API changes are included in the existing [release notes](/release-notes).