What is API Schema Diff (OpenAPI)?
API Schema Diff compares two OpenAPI documents in this browser: document A (old) and document B (new). It lists added and removed operations, then parameter and response changes on operations that exist in both. Breaking / compatible / uncertain labels are structural heuristics — they are not a contract-test guarantee and they do not run your clients. Remote $ref is not resolved. Specs stay in this tab; nothing is uploaded.
Key features
- Side-by-side paste of old (A) and new (B) OpenAPI documents
- Added, removed and changed operations
- Parameter and response change notes on shared operations
- Breaking / compatible / uncertain heuristic labels — review yourself
- Browser-local compare; remote $ref not resolved
Popular uses
- See which endpoints appeared or vanished between two spec versions
- Spot parameter or response edits before a release note
- Keep both documents on-device while you review a pull request
Supported formats
Paste two OpenAPI JSON/YAML documents. Compare stays in this tab.
Troubleshooting
- Everything is uncertain Large refactors and renamed paths look uncertain because the matcher is structural, not semantic.
Also known as: Swagger diff, OpenAPI compare, API breaking-change scan.
How it works
- Paste the old OpenAPI document (A) and the new one (B).
- Run the diff.
- Review added, removed and changed operations with compatibility labels.
FAQ
Are labels guaranteed?
No. Breaking / compatible / uncertain are structural heuristics. Always review for your clients.
Are breaking labels guaranteed?
No. They are structural heuristics. Always review for your actual clients and runtime.
Does it execute the APIs?
No. It diffs the documents you pasted. It does not call servers or generate client SDKs.