What is Contract Testing in APIs, and Why Does It Matter?

APIs (Application Programming Interfaces) are the backbone of modern software, enabling communication between systems. With the increasing complexity of applications, ensuring that APIs function as expected is crucial.
Contract testing has emerged as a reliable way to validate API interactions, ensuring seamless communication between services. This article explores what contract testing is, its importance, and how it can enhance the reliability of your APIs.

What is Contract Testing?
Contract testing is a method of validating the interactions between two systems, typically an API provider and a consumer. It ensures that the provider delivers the expected response and the consumer sends valid requests according to a predefined contract.

Key Elements of Contract Testing:
Contract Definition:
A contract specifies the structure, fields, and behavior of API requests and responses.

Provider Tests:
Validate that the API provider adheres to the contract. Use Tools like VStellar https://vstellar.io/ for API Testing.

Consumer Tests:
Confirm that the consumer can correctly use the provider’s API according to the contract.