# yaml

API design and documentation standard

Industry-standard specification for defining RESTful APIs with a comprehensive ecosystem of tools. OpenAPI Specification (formerly Swagger) describes endpoints, parameters, responses, and authentication in YAML/JSON format. Swagger UI generates interactive API documentation, Swagger Editor provides a visual spec editor, and Swagger Codegen generates server stubs and client SDKs in 40+ languages. The foundation of API-first development workflows used by millions of developers worldwide.

Built-in CI/CD for GitLab

GitLab's built-in CI/CD pipeline system defined via .gitlab-ci.yml files in your repository. Features multi-stage pipelines, parallel jobs, matrix builds, environments with deployment tracking, merge train for serialized merges, auto DevOps for zero-config CI/CD, container registry, and security scanning (SAST/DAST). Supports self-hosted runners and Kubernetes executors. Tightly integrated with GitLab's merge requests and issue tracking. A leading alternative to GitHub Actions for GitLab users.

Automate your workflow from GitHub

GitHub's built-in CI/CD and workflow automation platform that runs directly in your repository. Define workflows in YAML triggered by Git events (push, PR, release), schedules, or manual dispatch. Massive marketplace of 20,000+ community-maintained actions for testing, building, deploying, and automating tasks. Supports matrix builds, caching, secrets, environments with approval gates, and self-hosted runners. Free for public repos with generous minutes for private repos.