OpenAPI Breaking Change Checker
Compare two OpenAPI specs for removed paths, operations, responses, and newly required fields. JSON or YAML — runs in your browser.
Introduction
OpenAPI Breaking Change Checker is a free, browser-based utility in our API Tools collection. Paste baseline and updated OpenAPI 3 (JSON or YAML) documents to detect removed paths and operations, removed responses, newly required parameters or body fields, and parameter type changes — entirely in your browser. OpenAPI Breaking Change Checker helps you review API contract diffs before a release. Unlike a generic JSON diff, it understands paths, methods, parameters, responses, and required request-body properties so you can spot client-breaking changes quickly. Pair it with JSON Schema Validator when you need payload-level checks, or API Request Builder when drafting follow-up client snippets. Everything runs locally in your browser — inputs stay on your device, with no account or upload required. Highlights include openapi 3 json or yaml input.
Features
- OpenAPI 3 JSON or YAML input
- Removed paths and operations
- Removed response codes
- New/now-required parameters and body fields
- Parameter type change detection
How to use
- 1Paste the baseline (old) OpenAPI document on the left.
- 2Paste the candidate (new) document on the right.
- 3Review BREAK vs WARN findings and copy the report.
Example
Required query param added
InputGET /users adds required cursorOutput
BREAK [parameter.required_added] New required parameter query.cursor
Benefits
- Run OpenAPI Diff entirely in the browser with no signup or installation.
- Keep sensitive sample data private — processing never leaves your device.
- OpenAPI 3 JSON or YAML input
- Removed paths and operations
- Removed response codes
- Pair it with JSON Diff and JSON Schema when your workflow needs adjacent utilities.
FAQs
No. It focuses on common breaking-change heuristics for everyday PR review, not every OAS edge case or vendor extension.
Path/method style documents often work; prefer OpenAPI 3 for best results.
No. Comparison runs locally in your browser.
Yes. OpenAPI Diff on EverydayDevTools is free, with no account, watermarks, or usage caps for normal interactive use.
No. OpenAPI Diff runs in your browser. Your input is processed locally and is not sent to EverydayDevTools servers.
Paste baseline and updated OpenAPI 3 (JSON or YAML) documents to detect removed paths and operations, removed responses, newly required parameters or body fields, and parameter type changes — entirely in your browser. It fits everyday api tools tasks when you want a fast local utility instead of installing a CLI or opening a heavy IDE feature.
Core capabilities include: OpenAPI 3 JSON or YAML input; Removed paths and operations; Removed response codes; New/now-required parameters and body fields.
Developers often pair OpenAPI Diff with JSON Diff, JSON Schema, API Builder. Open Related tools on this page for quick links.