API
OpenAPI Diff / Breaking Change Analyzer
Paste or upload two API descriptions and review potentially breaking, additive, and informational contract changes without calling the API.
How this tool works
Contract compatibility is consumer-relative. Removing an operation or requiring a previously optional input is usually risky, while adding an operation is ordinarily additive. Response and schema interpretation can be more contextual.
The analyzer compares effective path-item and operation parameters, request-body requiredness, declared media types, response codes, selected schema constraints, effective security declarations, and deprecation flags. Filters help reviewers focus on a method, tag, or classification.
Examples
- Detect a removed GET operation.
- Flag an optional query parameter that became required.
- Separate enum narrowing from enum expansion.
Common use cases
Conservative classifications
- Removed operations, parameters, media types, and response codes, plus new requirements, type changes, and enum narrowing, are potentially breaking.
- Added operations, optional parameters, media types, response codes, and enum values are reported as additive, but strict consumers may still need review.
- Effective security and deprecation declaration changes are informational prompts for human analysis.
Known limitations
This remains a conservative structural analyzer. It cannot determine real consumer tolerance, runtime behavior, custom-extension semantics, every JSON Schema applicator, gateway behavior, deployment sequencing, or business semantics. Safe local references are resolved for the supported comparisons; remote references are rejected and never fetched.
Interpret findings in context
A finding is evidence for compatibility review, not a universal verdict about every consumer.
Failure case: OpenAPI Diff
Invalid/failure example
Separate enum narrowing from enum expansion.
Expected: The analyzer compares effective path-item and operation parameters, request-body requiredness, declared media types, response codes, selected schema constraints, effective security declarations, and deprecation flags. Filters help reviewers focus on a method, tag, or classification.
Related guides
Official references
FAQ
Does this tool send the pasted data or execute an API request?
No. Analysis runs in this browser tab. The tool does not call pasted URLs, resolve remote references, or submit the input to a DevPouch processing endpoint.
Does every flagged item break every client?
No. The analyzer intentionally says potentially breaking. Actual impact depends on consumer behavior, transport semantics, server tolerance, generated clients, and deployment policy.
Are remote references supported?
No. Bundle referenced schemas into one JSON or YAML document. The page rejects remote references and never fetches them.