[•]ContractLensAPI LAB
Offline contract analysisSource code ↗
KNOW WHAT YOUR API PROMISES

Ship changes.
Keep promises.

Catch contract mismatches before your consumers do.
Validate responses, review changes, and turn schemas into tests.

{ spec }→[ check ]→✓ ship

OpenAPI 3.0 · Python · JSON Schema

Synthetic data. No API key or account needed.
RESPONSE VALIDATION

Does the payload deliver?

{ }
GET/orders/{id}
·
JSON types, required fields, enums & bounds
Built for the boundary.Backend engineering meets practical QA.

OpenAPI 3.0.x JSON · Bounded schema subset · No remote references

Supported schema subset & input limits

Validation: objects, arrays, strings, numbers, integers, booleans, nullable, local references, required, enum, additionalProperties, bounds and uniqueItems. Formats are annotations. Composition, patterns, readOnly/writeOnly and discriminator are rejected explicitly. Maximum: 512 KiB per input; 12,000 nodes; 40 nested levels; 200 operations. Numeric schema bounds have magnitude 1e-9 to 1e12 or zero. Reference expansion: 20,000 nodes / 48 levels. Generation: 12 schema levels and 20 array items; unsupported constraints yield a clear error. Full OpenAPI specification validation is outside scope.