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oasdiff
What it is
oasdiff compares OpenAPI specifications, produces changelogs, and detects breaking changes before release. It supports OpenAPI 3.0, 3.1, and 3.2, and covers 755 distinct breaking and non-breaking changes. The CLI is available through Homebrew, a shell installer, Docker, and pre-built binaries for Linux, macOS, and Windows. Its output can be text, JSON, YAML, HTML, Markdown, or GitHub Actions annotations. The GitHub Action compares a pull request specification with a base branch and adds inline annotations for breaking changes. A browser diff tool compares OpenAPI or Swagger specifications without installation or sign-up. The hosted MCP server works with Claude, Cursor, and other Streamable HTTP MCP clients. Specs and changelogs are encrypted client-side before upload, leaving the server with ciphertext it cannot read. The engine, CLI, and GitHub Action are open source under Apache 2.0. The free plan includes CLI diffing, changelogs, GitHub Action annotations, side-by-side review, and encrypted spec storage. Pro costs $100/mo and includes approval workflows, an audit trail, a merge gate, and up to five reviewers across five repositories.
For and against
For
- Supports OpenAPI 3.0, 3.1, and 3.2.
- Free plan includes CLI diffing and changelogs.
- GitHub Action adds inline breaking-change annotations.
- Browser comparison requires no installation or sign-up.
- Specs and changelogs are encrypted client-side.
Against
- AsyncAPI is not supported.
- GraphQL is not supported.
- Free review links expire after seven days.
- Pro costs $100/mo.
The verdict
oasdiff offers a free route to specification comparison and release-change review, with Pro adding approval and merge controls. Teams should note the listed limits on review retention and supported contract formats.
Who it suits
oasdiff suits API teams that need to compare OpenAPI specifications, review changes, and identify breaking changes before release. The CLI, GitHub Action, and browser tool offer options for command-line, pull-request, and browser-based workflows.
Plans and prices
Free
CLI diff, breaking changes and changelog · GitHub Action inline PR annotations · side-by-side review · encrypted spec storage
Read 1 Oct 2026 · oasdiff.com
Pro
Approval workflow · audit trail · merge gate · up to 5 reviewers across 5 repositories
Read 1 Oct 2026 · oasdiff.com
Enterprise
Unlimited repositories and reviewers · SLA · dedicated support · optional no-upload GitHub mode
Read 1 Oct 2026 · oasdiff.com
On the record
- AI integrations
- oasdiff provides a hosted MCP server that works with Claude, Cursor, and other Streamable HTTP MCP clients.oasdiff.com · read 1 Oct 2026
- Browser tool
- The web diff tool compares OpenAPI or Swagger specifications without installation or sign-up and exports text, YAML, JSON, Markdown, and HTML.oasdiff.com · read 1 Oct 2026
- Change coverage
- oasdiff detects 755 distinct breaking and non-breaking API changes.oasdiff.com · read 1 Oct 2026
- CLI installation
- The CLI is available through Homebrew, a shell installer, Docker, and pre-built Linux, macOS, and Windows binaries.oasdiff.com · read 1 Oct 2026
- Encryption
- Specs and changelogs are encrypted client-side before upload, and servers retain only ciphertext that oasdiff cannot read.oasdiff.com · read 1 Oct 2026
- Enterprise privacy
- Enterprise can load specs directly from GitHub at review time using each reviewer's access without uploading or storing specs.oasdiff.com · read 1 Oct 2026
- GitHub integration
- The GitHub Action compares pull-request and base-branch specifications and adds inline breaking-change annotations.oasdiff.com · read 1 Oct 2026
- Microservices
- Composed mode compares collections of OpenAPI files together for APIs split across multiple services.oasdiff.com · read 1 Oct 2026
- OpenAPI support
- oasdiff supports OpenAPI 3.0, 3.1, and 3.2.oasdiff.com · read 1 Oct 2026
- Open source
- The oasdiff engine, including its CLI and GitHub Action, is open source under the Apache 2.0 license.oasdiff.com · read 1 Oct 2026
- Output formats
- CLI output supports text, JSON, YAML, HTML, Markdown, and GitHub Actions annotations.oasdiff.com · read 1 Oct 2026
- Purpose
- oasdiff compares OpenAPI specifications, generates changelogs, and detects breaking changes before release.oasdiff.com · read 1 Oct 2026
- Review retention
- Free review links expire after 7 days, while Pro reviews remain for the life of the pull request.oasdiff.com · read 1 Oct 2026
- Support
- oasdiff provides support and security or procurement contact through [email protected].oasdiff.com · read 1 Oct 2026
