Contract Testing
Catch Breaking API Changes Before They Hit Production
Validate every API response against your OpenAPI contract. Detect schema drift, missing fields, and type mismatches automatically on every test run.
How contract drift causes production failures
Schema drift
The API implementation slowly diverges from the documented spec. New fields appear, types change, required fields become optional.
Consumer breakage
Frontend apps and mobile clients break because the API returned a different response shape than the spec promises.
Undetected breaking changes
A developer changes a response field name. Functional tests still pass because they don't validate the contract.
No spec enforcement
The OpenAPI spec is documentation — nobody validates that the actual API matches it.
Manual contract review
Teams manually review API changes in pull requests. Subtle type changes and optional-to-required shifts get missed.
Late discovery
Contract violations are found in integration testing or production — not at the API level where they originate.
Why functional tests aren't enough
Functional tests verify behavior. Contract tests verify the shape. You need both.
How contract testing works in Total Shift Left
Import your OpenAPI spec as the contract
Your OpenAPI specification is the source of truth. Every endpoint, schema, required field, and type constraint becomes a contract rule.
AI generates contract-aware tests
Generated tests include contract validation: response status codes, field types, required fields, enum values, and nested object shapes are all checked.
Run tests to detect drift
Every test run validates responses against the spec. Schema drift — where the implementation doesn't match the contract — is flagged immediately.
Gate deployments on contract compliance
Configure CI/CD quality gates to fail builds when contract violations are detected. No broken contracts reach production.
Every run
Contract validation on every test
Schema-level
Field types, required, enums
Automatic
No separate contract setup
CI/CD gates
Block on contract violations
Frequently asked questions
What is API contract testing?
API contract testing validates that your API's actual responses match the schema defined in your OpenAPI specification. It checks response status codes, field names, data types, required fields, enum values, and object structure — catching drift between the spec and the implementation.How is this different from consumer-driven contract testing (Pact)?
Pact requires consumers to define their expectations. Total Shift Left derives the contract from your OpenAPI spec — which already defines the expected behavior. No separate contract setup, no consumer-side configuration.Do I need to set up contracts separately?
No. If you have an OpenAPI or Swagger spec, you already have a contract. Total Shift Left uses your existing spec as the contract definition and validates responses against it automatically.What types of contract violations are detected?
Type mismatches (string instead of integer), missing required fields, unexpected additional fields, enum value violations, status code mismatches, and nested object schema drift.Can I use this with microservices?
Yes. Each microservice has its own OpenAPI spec and its own contract validation. The platform tracks contract compliance across all services independently.How do I enforce contracts in CI/CD?
Configure quality gates to fail the build when contract violations are detected. This prevents deploying API changes that break the documented contract.
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