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API Diff Checker

Compare two OpenAPI specs side-by-side to detect breaking changes, new endpoints, removed fields, and modified schemas between versions. Code never leaves your device — formatting and validation run locally in your browser.

100% Local Browser Native

How to Use the API Diff Checker

1. Paste both API responses

Baseline and current JSON/XML payloads from the same endpoint.

2. Run the diff

Added, removed, and changed fields highlight with paths.

3. Triage breaking changes

Removed fields and type changes break clients — added optional fields usually do not.

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Frequently Asked Questions

Spec diff or traffic diff?

Spec diff — OpenAPI v1 against v2, structural changes highlighted.

Breaking changes flagged?

Removed endpoints, narrowed types, and new required fields surface first.

Export the diff?

Markdown and JSON reports for review threads, CI gates, and pull requests.

Are my specs uploaded anywhere?

No — comparison runs locally in your browser, free with no signup.

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Last updated October 2026