API Automation Testing Tools

REST Assured

• A Java library that allows interaction with HTTP based REST APIs.
• Simple to write tests in and assert truthfulness of responses.
• Does require some Java knowledge to design and develop tests.
• This library is open source and free.
• Can be found at https://rest-assured.io/

Postman

• A standalone REST client that allows codeless tests to endpoints.
• Very easy to use, the codeless nature allows you to create tests quickly with smaller margin for error.
• Using Numan, test can be executed via in CLI.
• This tool is free but has a licensed ‘pro’ option for more features.
• Can be found at https://www.postman.com/

SoapUI

• A more complex Soap client that integrates with SOAP APIs
• More weighted towards complex APIs with heavy dependency on QA/testing.
• Can create custom workflows in Groovy, which provides better efficiency.
• This tool is free but has a licensed ‘pro’ option.
• Can be found at https://www.soapui.org/

JMeter

• A Java application more focused on performance and load testing, JMeter can still offer powerful functionality to test REST APIs.
• A codeless but complex test design style, tests are built with custom objects in a test plan, which there are public plugins to extend the functionality.
• Allows for API response assertions and also able to load these APIs to test the performance.
• Integrates very nicely into CI/CD as JMX files that can be run from CLI.
• This tool is open source and free.
• Can be found at https://jmeter.apache.org/