API Testing

API testing checks whether application programming interfaces behave as expected when they receive requests and return responses. It helps teams verify endpoints, data formats, authentication, error handling, and performance, catching problems before they affect users or other services. Tests can be run manually during development or automated as part of continuous integration, and may cover REST, GraphQL, and other HTTP-based interfaces.

Open source tools in this area include request-building clients, automated test runners, traffic-based test and mock generators, and security scanners. When choosing one, consider supported protocols, scripting and automation options, integration with existing workflows, setup requirements, license terms, and maintenance activity. API testing tools are useful to developers, quality engineers, security teams, and organizations that build or depend on APIs.