Documentation

The scriptable control plane for API contracts — for humans, CI pipelines, and AI agents.

Spec0 is a developer-tools platform for the full lifecycle of an API contract: a searchable registry, hosted mocks, quality gates, and discoverable contracts that AI agents can compose.

Getting started

Five-minute tour: publish your first spec, spin up a mock, gate CI on breaking changes.

Concepts

Mental model — registry, specs, mocks, governance, versioning.

Platform

The web app — registry, teams, subscriptions, governance.

CLI

@spec0/cli — same surface humans use is what CI and agents automate against.

Mock server

Self-hosted or platform-managed — variants, validation, CEL expressions.

AI agents

Capability discovery, structured errors, the docs MCP server.

Spec0 is designed so the same operations are available from the terminal, the dashboard, CI runners, and AI agents. A spec0 publish from a developer, a GitHub Actions workflow, and an agent calling the CLI through MCP all hit the same registry, the same governance gates, the same mock provisioning.

Where to start

First time? Getting started walks you from npm install to a published spec with a live mock URL.
Coming from a CI pipeline? GitHub Actions guide shows the non-interactive flow with stable exit codes.
Building an AI agent? Agent playbook covers capability discovery, JSON output, and the MCP server.