OpenAPI / Swagger Diff Checker
Compare OpenAPI or Swagger JSON/YAML files for added, removed, and potentially breaking API changes.
What is OpenAPI / Swagger Diff Checker?
Compare OpenAPI/Swagger operations, responses and structural contract changes. Added request requirements and removed response guarantees can break consumers in different ways.
How to use OpenAPI / Swagger Diff Checker?
Step 1
Paste or upload the old OpenAPI/Swagger file.
Step 2
Paste or upload the proposed new spec.
Step 3
Review removed endpoints, added endpoints, response changes, and manual schema-review notes.
Example input / output
Removing POST /users is an operation removal. Changing a requestBody, parameters or shared component is flagged for review even when every endpoint path still exists. Path-level parameters are metadata, not HTTP methods.
Example input
openapi: 3.0.3
info: {title: Demo, version: "1"}
paths:
/users:
get:
responses:
"200": {description: OK}Check the result
- Schema compatibility can depend on generated clients, nullable behavior, and required fields; review flagged changes carefully.
- Invalid YAML indentation or unsupported vendor extensions can prevent parsing.
Practical developer examples
Follow shared references
A component update can affect many operations. Inspect consumers of the changed schema and use representative contract tests to determine impact.
Consider change direction
Requiring another request field can reject existing clients; allowing fewer response fields can remove an existing guarantee. A raw diff alone cannot label every change safe or breaking.
Common developer use cases
This is a structural review, not a complete compatibility verifier. External refs, callbacks, webhooks and every schema keyword are not exhaustively compared.
Common issues
FAQ
Does zero removed operations mean no breaking change?
No. Types, required fields, enums, status codes and security can change without removing a path.
Does the tool fetch external $ref URLs?
No. Comparison stays local; review referenced documents separately.