API

GitLab exposes three flavors of API.

API	Path	Source	Page
REST	/api/v4/...	lib/api/, ee/lib/api/	REST API
GraphQL	/api/graphql, /api/graphql_subscriptions	app/graphql/, ee/app/graphql/	GraphQL API
Internal	/api/v4/internal/...	lib/api/internal/	Internal API

In addition there are smaller specialized APIs:

• MCP API (/api/v4/mcp) — Model Context Protocol endpoints for AI tooling, plus OAuth discovery.
• GLQL API (app/controllers/glql/) — Saved queries and saved-search execution.
• Geo internal API (EE-only) — secondary-to-primary callbacks.
• SCIM API (EE) — ee/lib/api/scim/ for SAML group provisioning.

The REST API is the primary public API; new public functionality is generally added there first or to GraphQL.