Find breaking Swagger changes without reading raw YAML
Line-by-line diffs are noisy when API files are generated or reformatted. A contract-aware comparison focuses on changes that affect callers.
Parse the API document
Contract Guard reads OpenAPI 3.x JSON and YAML as structured API definitions instead of treating the file as plain text.
Classify compatibility
The report separates breaking changes from compatible additions and shows the affected HTTP operation or schema location.
Give reviewers a clear answer
A concise pass or fail result is easier to review than hundreds of generated YAML lines and makes accidental contract breaks harder to miss.
Enforce it on pull requests
The GitHub check runs as part of the normal pull-request workflow, without requiring developers to remember a separate command.
Protect every pull request automatically
Install the GitHub App, choose a repository and get a clear pass or fail status whenever its OpenAPI contract changes.
Frequently asked questions
Is Swagger the same as OpenAPI?
Swagger is commonly used to refer to OpenAPI descriptions. The public checker currently requires an OpenAPI 3.x document.
Will description changes fail the check?
No. Documentation-only edits are not consumer-breaking contract changes.
Can generated specifications be checked?
Yes. Commit the generated specification or generate it before the pull-request check can read it.
Is there a free trial?
Yes. Starter protects up to 3 repositories for 14 days without requiring a card.