About
What is APIDiffGuard?
APIDiffGuard monitors live API responses against versioned baselines, detects JSON schema drift and breaking field changes, and helps teams catch contract breaks before production. Free JSON Diff, Formatter, and Validator tools run in the browser without an account; Cloud hosts baselines and checks for you.
What problem does it solve?
Partner and internal APIs change shape without warning. Unit tests of your code miss those breaks. APIDiffGuard replaces ad-hoc curl scripts with baselines, scheduled or CI checks, and a severity-aware JSON diff so teams see removed fields and type changes before customers do.
How does API monitoring differ from a JSON Diff?
A JSON Diff compares two static payloads once. APIDiffGuard stores a baseline from a live endpoint, re-fetches on demand or on a schedule, and alerts when the live response drifts. The free Diff tool uses the same comparison engine for one-off investigations.
Try the free JSON Diff or read concepts.
Is APIDiffGuard open source?
Yes. The repository is MIT open-core. You can self-host, reuse the @apidiffguard/diff package, and use free tools publicly. The commercial product is hosted Cloud convenience — auth, workspaces, and managed monitoring — not a lock on the diff algorithm.
Key terms
- Schema drift
- Unplanned change in an API response structure over time, such as removed fields, type changes, or new required properties that break clients.
- API baseline
- A versioned snapshot of a known-good API response (status, headers, body) used as the contract to compare future checks against.
- Breaking API change
- A response change that is likely to break clients — for example a removed field, a type change, or an HTTP status class change from success to error.
FAQ
- What is APIDiffGuard?
- APIDiffGuard is developer software that monitors live API responses against versioned baselines, detects JSON schema drift and breaking field changes, and helps teams catch contract breaks before production. It also offers free browser JSON Diff tools.
- Who is APIDiffGuard for?
- Backend and platform engineers, agencies integrating partner APIs such as Stripe, and teams that want CI gates on response contracts instead of ad-hoc curl scripts.
- How is APIDiffGuard different from uptime monitoring?
- Uptime tools usually check HTTP status. APIDiffGuard compares response shape — removed fields, type changes, and status class flips — so you catch silent contract breaks, not just downtime.
Machine-readable map: llms.txt · llms-full.txt