SpecShield — catch breaking API changes before they reach your consumers

SpecShield is contract compatibility testing for APIs. It compares the OpenAPI description in your branch against the last published version, flags anything that would break an existing consumer, and posts the result as a GitHub check — so a breaking change is caught in review, not in production.

What SpecShield does

  • Breaking-change detection. SpecShield flags removed endpoints, tightened types and newly required fields on every pull request.
  • Consumer-aware deploy gate. SpecShield's can-i-deploy gate blocks a merge when a change would break a consumer you have registered — not when a human forgot to approve it.
  • Consumer registry. SpecShield records which services depend on your API, so the gate has something real to decide against.
  • API governance. SpecShield scores your OpenAPI description against OWASP and design rulesets and returns a 0-100 score with a letter grade.
  • Where you already work. A GitHub App and Action, a CLI for any CI, an IntelliJ plugin, SARIF output for code scanning, and an MCP server for AI agents.

Free tier

SpecShield is free forever for one user, including unlimited spec comparisons, breaking-change detection in CI, and one GitHub App PR check. Team is $89/month for up to 10 users.