API First Implementation

APIs form the nerve center of software applications. So, it is important for the providers to be clear about what they might provide and consumers to be clear about what they want to consume. Better understanding of APIs guarantees an excellent output. API First is all about the establishment of a common agreement between the providers and consumers. Thus, this design helps both the parties to be on the same page.

When you adapt the API First approach, as an API developer you can start the API development with the API contract. You can work on the implementation part at a later stage. This approach of prioritizing the API design over its implementation is beneficial to both providers and consumers.

In conventional scenarios, providers expose APIs to their consumers only after the API is implemented. Consumers test the API and provide their feedback about the API to the providers. Providers must then revisit the API to incorporate the feedback received from their consumers. You can optimize this process by adapting API First design.

With the API First approach, the consumers do not have to wait for the provider to implement the API, but can proceed with their application development by using the exposed API. The implementation status of the API does not have an impact on consumers as they receive the designated responses for their requests through the mocked API. So, the API development and the application development can take place at the same time.

After the provider implements the API, the end point is updated to divert the invocations to the actual implementation instead of the mocked response. The provider can then disable mocking.

The following diagram explains the flow of API development according to the API First design.

According to the API First design, providers expose their API to consumers when the development is underway.