Your files stay on your device

OpenAPI specification diff checker

Compare two OpenAPI documents and see every change to paths, parameters, schemas, security, and responses classified as breaking or not.

Paste or open two OpenAPI documents and press Compare. The examples load a breaking major release and a safe patch of the same little orders API.
The rule set, and what this tool does not do

Requests and responses are judged in opposite directions, because the consumer sits on the other side of each. Breaking: a removed operation or path, a new required parameter, a request that accepts less (a narrower type, a shrunken enum, a closed additional-properties map), a response that loses a field or value, a removed success status, and authentication added to a call that was public. Non-breaking: new paths, optional parameters, wider request types, extra response properties. Review: everything that depends on the client, like a new response enum value against an exhaustive switch, a new status code, a changed operationId, or a combinator reshuffle. Info: version numbers, server URLs, titles, deprecations, and renamed path parameters.

Known limits:

- OpenAPI 3.x only; Swagger 2.0 documents are refused with a clear message.
- Remote $ref files are never fetched; a reference the tool cannot follow is reported as review, not guessed at.
- Webhooks, callbacks, examples, and link objects are not compared.
- YAML anchors, aliases, merge keys, and tags are refused rather than expanded.
- Changes inside components.schemas surface at every operation that uses them, plus a note when a named schema is added or removed.
OptionsCompare

More regex & cron tools

- JSON diff (/json/diff)
- JSON schema validator (/json/schema)
- Semver compare (/dev/semver)
All regex & cron tools (/dev)

Was this tool useful?
YesNo

Canonical HTML: https://nutter.tools/dev/openapi-specification-diff-checker
Markdown version: https://nutter.tools/dev/openapi-specification-diff-checker.md
Plain-text version: https://nutter.tools/dev/openapi-specification-diff-checker.txt
Agent index: https://nutter.tools/llms.txt