Concepts
API Drift
API drift happens when your API's implementation no longer matches its published specification, such as an OpenAPI document.When that mismatch grows over time, the contract stops being a reliable description of the real API.
The Problem
As APIs evolve, developers might add fields, change data types, or modify status codes. If the specification is not updated at the same time, client applications that rely on it can fail, and supporting documentation can quickly become misleading.
The Drift Solution
Drift is a spec-first testing tool that helps keep your implementation aligned with your API contract. It does that in three main ways:
1. Specification as the source of truth. Tests map directly to the operations defined in your OpenAPI document.
2. Deep schema validation. Drift validates response bodies against the JSON schemas in your specification.
Repeatable CI/CD validation. By running Drift in automation, you can catch drift before it reaches production.