What is API testing?
API is an acronym for Application Programming Interface.
In software application (app) development, API is the middle layer between the presentation (UI) and the database layer. APIs enable communication and data exchange from one software system to another.
API testing is a software testing practice that tests the APIs directly — from their functionality, reliability, performance, to security. Part of integration testing, API testing effectively validates the logic of the build architecture within a short amount of time.
Where is API testing performed?
There are three separate layers in a typical app: the presentation (or user interface) layer, the business layer, and the database layer for modeling and manipulating data.
API testing is performed at the most critical layer: business, in which business logic processing is carried out and all transactions between the user interface and database layers happen.
Benefits of API testing
Data is exchanged via XML and JSON formats, so any language can be used for test automation. XML and JSON are typically structured data, making the verification fast and stable. There are also built-in libraries to support comparing data using these data formats.
API testing can be performed in the app prior to GUI testing. Early testing means early feedback and better team productivity. The app's core functionalities can be tested to expose small errors and to evaluate the build's strengths.
Improved test coverage
Most API/web services have specifications, allowing you to create automated tests with high coverage — including functional testing and non-functional testing.
It is common that executing API testing saves up to eight hours compared to UI testing, allowing software development teams to release products faster.
API Testing Types
Runtime and error detection
Why Katalon for API Testing
Productive IDE for API automation
Optimize the processes of scripting, debugging, and maintaining tests with autocompletion, code inspection, snippets, quick references, debugger, dual interface, and so on.
Katalon supports all types of REST, SOAP/1.1 and SOAP/1.2 requests. Your tests can be imported from Swagger, Postman, and WSDL.
Built to work with modern frameworks
Data-driven testing made simple with multiple data sources (e.g. XLS, CSV) and databases supported. Katalon also supports BDD with Cucumber files and native Gherkin editor.
Sustainable and scalable platform
Enable CI and DevOps practices with built-in integrations. Easy deployment with Docker containers. Local and remote execution with real-time analytics.
Reuse test artifacts across different projects. Define test scenarios and execution plans with test suite management capabilities.