API-First Design
API-First Design refers to the practice of designing the API interfaces before any implementation of the functionality they expose. This method prioritises the development of API specifications as the first step in the development process.
Goal
The goal of API-First Design is to establish clear and concise contracts for APIs that guide the development of the system’s components. This enables parallel development, reduces integration issues, and ensures a more cohesive and flexible architecture.
Context
Modern systems are often composed of multiple services and components that need to interact seamlessly. In addition, customers often want an API to be able to integrate with their own systems. By designing the API first, teams can ensure that the API is well-defined and meets the needs of the system and its users.
Inputs
| Artifact | Description |
|---|---|
| User Stories | Detailed descriptions of the functionality, performance criteria, and interfaces needed for each component. |
Outputs
| Artifact | Description | Benefits |
|---|---|---|
| API Specification | A detailed description of the API’s endpoints, data models, and authentication methods. | Provides a clear contract for development, facilitating parallel development and easier integration. |
Anti-patterns
- Designing APIs in isolation: The API is the customer experience of your product. Therefore you should involve customers in the design process and ensure that the API meets their needs.
- Failing to maintain specification: The API specification should be a living document that evolves with the system. Failing to maintain the specification can lead to confusion and integration issues.