Development

OpenAPI Diff & Breaking Change Checker

Compare two OpenAPI 3 JSON or YAML documents and identify endpoint, parameter, response, and schema changes with breaking-change classification.

Free to use No sign-up Runs in your browser

Tool workspace

5
Total
2
Breaking
3
Non-breaking
3
Added
0
Removed
2
Changed
BreakingChanged Schemacomponents.schemas.Pet

removed properties: name; added required properties: species; newly required: species

BreakingChanged ParameterGET /pets parameter query:limit

Parameter became required.

Non-breakingAdded Path/owners

Path added.

Non-breakingAdded MethodGET /owners

Operation added.

Non-breakingAdded ResponseGET /pets response 404

Response added.

What Is an OpenAPI Diff Tool?

An OpenAPI diff compares two API contract versions structurally instead of treating them as plain text. This tool reports added, removed, and changed paths, HTTP operations, parameters, responses, and component schemas, then classifies compatibility risks that can break existing clients.

How to Compare OpenAPI Documents

  1. 1Paste the original OpenAPI 3 document on the left.
  2. 2Paste the updated JSON or YAML document on the right.
  3. 3Review the change totals and breaking-change count.
  4. 4Inspect each finding before publishing or versioning the API.

Common API Contract Checks

Release Review

Detect removed operations, required parameters, and incompatible schemas before deployment.

API Versioning

Decide whether a contract update needs a major version or migration guide.

Consumer Coordination

Create a concise inventory of changes for SDK and integration owners.

Frequently asked questions

Which OpenAPI versions are supported?

The parser accepts OpenAPI 3.x documents in JSON or YAML.

What is classified as breaking?

Examples include removed paths or operations, removed responses or schemas, newly required parameters or properties, and changed parameter or property schemas.

Are external references resolved?

No. The comparison is local and structural; bundle external references first when their resolved content must be compared.