Documentation

Guides & reference

The full docs live alongside the source in the API Circle repository. Start with a guide below, or browse everything on GitHub.

Getting started

Installing the desktop app

Download, first-launch prompt, and one-time setup.

Connect your AI client

Per-client MCP setup for Claude, Cursor, Copilot, ChatGPT, and more.

README & quick start

The 60-second tour of both usage modes.

Guides

Mock server guide

Spin up mocks, override responses, add rules and validation.

Authentication matrix

All 17 auth schemes and how each is configured.

MCP tool catalog

Every tool the 94-tool MCP catalog exposes.

Architecture & reference

Platform architecture

The design record behind MCP, the mock engine, CLI, and desktop.

Migration guide

Workspace storage relocation across versions.

QA & coverage

QA status, E2E CI reference, and coverage tooling.

Two ways to use it

Local, or Git-backed

The workspace lives in different places depending on what you're doing. Pick the mode that matches.

Mode A

Local workspace

Open the desktop or web app and a workspace is created automatically in browser storage. No folder to manage, no flags. The easiest way to start — and how you create the workspace you’ll later link to Git.

Mode B

Git-backed workspace

Use Link to Git to bridge your workspace to a GitHub repo. The cloned directory is the workspace — pass it to the CLI or MCP server with --workspace for teams, CI, and headless agents.

Read the source, drive the product

API Circle is source-available and built in the open. Browse the code, file an issue, or open the app and start building.

Open the web app Download for desktop