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Start with OpenAPI 3.0 or 3.1 JSON, or supported YAML. Local component references are resolved without network access.
DEVELOPER INTELLIGENCE CONTRACT AUDIT STUDIO
API Contract Drift Detector
Compare OpenAPI contracts with real request and response captures—or compare two contract versions. Trace breaking changes, type mismatches, missing fields, and unexpected endpoints without sending data to a server.
✓ OpenAPI 3.0 / 3.1✓ Request + response validation✓ Version diff✓ Exportable findings
AUDIT WORKSPACE
API Contract Drift Detector
01
Reference API specification
OpenAPI JSON or common YAML syntax. The baseline never leaves this device.
Paste below or choose a file
Supports internal $ref, request bodies, JSON response schemas, parameters and status codes. Maximum 4 MB.
02
Captured traffic samples
Upload request/response pairs, HAR, or line-delimited JSON.
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Sample format and supported fields
Each sample uses method, path or url, status, optional request.body, request.headers, request.query, response.body and response.headers. A browser HAR export is also accepted. Missing HTTP status is reported as unverified, not silently treated as 200. Captured bodies must be valid JSON values for JSON-schema checks.
02
Candidate API specification
Compare endpoints, response fields, constraints and request requirements.
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Classification is directional: the first specification is the current/baseline contract, and this one is the proposed/new contract.
API samples may contain secrets. Review before exporting reports. This editor never sends them anywhere.
Ready. Load the demo or paste a contract and samples.
COMPATIBILITY REPORT
Not analyzedDrift findings
Potential breaking—Contract violations / risky changes
Warnings—Coverage or potential risk
Informational—Unspecified / newly added
Samples / endpoints—Awaiting analysis
Observed operation coverage appears here after analysis.
This is a local static analysis, not a live API tester. Evidence from observed samples cannot guarantee forward or backward compatibility.
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Your drift report starts here
Use the demo to see how mismatched types, missing properties and undocumented statuses are surfaced.
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03
Share your findings
Export the analysis for pull requests, QA tickets or CI follow-up.
Reports use operation templates rather than observed URL IDs; unmatched URLs are withheld. Reports do not contain raw request or response bodies. Review potentially sensitive field names before sharing.
Potential breaking means a violation was observed or a change is likely incompatible. Warnings require review. An empty report only means no supported checks found issues in the supplied evidence.
Find problems before your clients do.
Compare real traffic
Import request/response samples or HAR captures. Detect nested field mismatches, required-property gaps, status changes, and additional fields.
Prioritize fixes
Filter by risk and export JSON or CSV reports. Or compare two versions of an OpenAPI contract before release.
FAQ
Does the tool call my API?
No. There is no endpoint probing, URL fetching, secret storage, backend or cloud processing. It works only on files and text you provide.
Does it fully implement JSON Schema 2020-12?
No. It performs practical checks for common OpenAPI constraints and internal references. Complex schema dialect features, discriminators, conditional keywords, external references and arbitrary YAML features are not fully supported.
Does a green report mean an API is backward compatible?
No. Samples are evidence, not exhaustive proof. Dynamic behavior, authentication, semantics, client assumptions and untested schema branches can still be incompatible.
What format should my samples use?
Use an array of objects with method, path, status and optional request/response bodies, NDJSON records or HAR data. Review or redact credentials and personal information before saving or sharing.