Find breaking OpenAPI changes before your users do.
A small contract edit can break every client that depends on your API. Compare the proposed specification with the current one and turn risky changes into a visible pull-request check.
Removed operations and responses
Catch deleted paths, HTTP methods and success responses that existing integrations may still call or expect.
New required inputs
Flag parameters or request properties that become mandatory, because existing clients cannot provide fields they were never built to send.
Incompatible schema edits
Surface response properties, types and constraints that no longer match the contract your consumers integrated against.
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
What is a breaking OpenAPI change?
It is a contract change that can cause a previously valid API client to fail, such as removing an endpoint, removing a response or adding a required input.
Does it support YAML and JSON?
Yes. API Contract Guard compares OpenAPI specifications written in either YAML or JSON.
Can it block a GitHub pull request?
Yes. The GitHub App reports a failed check when it detects a breaking contract change, so branch protection can prevent the merge.