A comparison between OpenAPI with Renovate to Contract Tests
APIs are at the heart of modern software architectures. They connect services and are used in frontend featured applications. But as systems grow and change, APIs do the same, especially when multiple teams need to move independently. Even the smallest change in one endpoint can break critical features in independent teams and often, traditional integration testing catches it too late.
In this talk, we’ll look at two strategies that are commonly used when it comes to managing API contracts safely and efficiently.
The first approach builds on the combination of OpenAPI, Renovate, and automated code generation. When APIs are defined through OpenAPI specifications, it is possible to generate type-safe clients and server stubs. Add Renovate to the mix, and you can detect API spec changes and trigger automated pull requests for updated generated code in your repositories.
The second approach is contract testing—usually implemented as Consumer-Driven Contract Testing. Here, each consumer defines their expectations of the API interface as a machine-readable contract. These contracts are verified any time the provider code changes. If a change violates an existing contract, the test fails, preventing regressions before they reach production.
Let us have a look together on both approaches and compare them to the one you use at the moment.