API & Web
Processed locally
OpenAPI Breaking Change Analyzer
Compare an old and a new OpenAPI/Swagger spec (JSON or YAML) and see every change classified breaking, risky, safe, or doc-only — with a verdict you can gate a release on. Runs in your browser; nothing is uploaded.
Auto-compares as you type. Ctrl+Enter to re-run.
How to use the OpenAPI Breaking Change Analyzer
Paste two versions of an OpenAPI or Swagger specification — the old baseline and the new candidate — and instantly see what changed, with each change classified as breaking, risky, safe, or doc-only. Use it in code review and release checks to catch contract regressions before they reach clients. Both files are parsed and compared entirely in your browser; nothing is uploaded.
What it does
- Detects removed paths, operations, and response codes (breaking).
- Flags added or now-required parameters and request bodies (breaking).
- Compares component schemas: removed properties, type changes, and enum removals.
- Separates documentation-only edits so they don't drown out real changes.
When to use it
- Reviewing an API pull request before merge.
- Deciding whether a release needs a major version bump.
- Auditing a vendor's spec change for client impact.
- Documenting a changelog of API changes.
How to use it
- Paste the old spec on the left and the new spec on the right (JSON or YAML).
- Read the severity summary, then the grouped change report.
- Copy the report into your PR or changelog.
Tips & pitfalls
- Schema changes are classified conservatively — a newly required property is marked risky because it is breaking for request bodies but safe for responses.
- The analyzer resolves internal
$refs; very deepallOf/oneOfcomposition is summarized, not fully merged. - Removed enum values are breaking for response consumers that switch on them.
FAQ
- What counts as a breaking API change? A breaking change is one that can break existing clients: removing a path, operation, or response; adding a required parameter; making a parameter or request body required; changing a type; or removing an enum value. This tool flags those as breaking, with less severe changes marked risky, safe, or doc-only.
- Can I paste YAML specs, not just JSON? Yes. Paste either JSON or YAML for each spec. The tool parses JSON first and falls back to YAML, so OpenAPI and Swagger files in either format work.
- Are my specs uploaded anywhere? No. Both specs are parsed and compared entirely in your browser. Nothing is sent to any server.