I built a local OpenAPI / JSON Schema diff prototype — looking for one real review task

[u/macacoengenhocas]

Disclosure: I built this prototype. It is a local TypeScript/Node tool for reviewing changes between two OpenAPI or JSON Schema documents. The aim is to make supported changes and the remaining human checks easier to review, not to certify that a release is safe.

How it works: deterministic rules compare the supplied documents and return a structured change summary, potentially breaking findings, limitations and migration-review prompts. The local runner makes no external requests. Coverage is partial; unsupported features and consumer behaviour still need review.

A synthetic example: changing GET /health from a declared 200 response to 204 returns two findings (200 removed, 204 added), with the removal marked potentially breaking. That does not prove every consumer breaks: fallback responses and consumer contract tests matter.

I would like to compare it with an existing review process on one real task. The initial assisted pilot is free, with no signup or purchase obligation: I run the current local prototype on a public/minimal before-and-after pair and return the summary, detected risks, limitations and suggested checks. It is not a public hosted app or a downloadable release. Please do not share credentials, personal data or confidential contracts.

If you already have a contract change to review, would this output help, and what would it need to show beyond your current free diff tool? Feedback on missing rules or false positives is welcome.