API Contract Checker
Local JSON only: OpenAPI 3.0.x/3.1.x, 1 MiB each, depth 64, 100,000 values, first 500 findings. Reports removed paths/operations/responses and optional-to-required parameters, request bodies and top-level inline request fields. External references and YAML are rejected. Internal references are skipped. No response-schema, nested-schema, complete breaking-change, equivalence or schema-validation analysis.
A QUICK WALKTHROUGH
How to use this tool
- Paste the original and changed OpenAPI JSON specifications.
- Run the bounded comparison locally.
- Review listed changes and skipped scopes; review other compatibility risks separately.
API Contract Checker
Local JSON only: OpenAPI 3.0.x/3.1.x, 1 MiB each, depth 64, 100,000 values, first 500 findings. Reports removed paths/operations/responses and optional-to-required parameters, request bodies and top-level inline request fields. External references and YAML are rejected. Internal references are skipped. No response-schema, nested-schema, complete breaking-change, equivalence or schema-validation analysis.
GOOD TO KNOW
Common questions
What does the checker compare?
It reports removed paths, operations, and responses, plus optional-to-required changes for parameters, request bodies, and top-level inline request fields.
Does it analyze every breaking change?
No. It skips internal references and does not analyze response or nested schemas, full breaking-change coverage, semantic equivalence, or schema validity.
What inputs and limits are supported?
It accepts OpenAPI 3.0.x or 3.1.x JSON up to 1 MiB per file, depth 64, and 100,000 values; it shows at most 500 findings. YAML and external references are rejected.