API & OpenAPI utility
OpenAPI Breaking Change Checker
Flag removed operations and newly required request fields between API specs.
● This tool runs entirely in your browser. Your input is never uploaded to our servers.
Output
Your result will appear here…
How to use OpenAPI Breaking Change Checker
- Paste the old spec and the new spec separated by === TARGET ===.
- Select Check Changes to flag common breaking endpoint changes.
- Review findings with your API compatibility policy.
Example
Input:
{"openapi":"3.0.3","info":{"title":"Example","version":"1"},"paths":{"/users":{"get":{"responses":{"200":{"description":"ok"}}}}}}
=== TARGET ===
{"openapi":"3.0.3","info":{"title":"Example","version":"2"},"paths":{}}Output:
Breaking change: GET /users was removed.
Use cases
- Review endpoint removals before deployment.
- Check contract changes during code review.
- Find obvious compatibility risks in local specs.
About this tool
Flag removed operations and newly required request fields between API specs. Processing happens locally in your browser, so your input is not sent to a server or included in analytics.
Frequently asked questions
Does this guarantee backward compatibility?
No. It checks common path and operation removals and cannot detect every schema or behavior change.
Does it call the API?
No. It only compares the provided specification text.
Can it resolve references?
No. External and internal reference targets are not fully resolved by this lightweight checker.