API testing tools

Open Source

  • Astra: A Python-based tool for API Automated Security Testing.

  • Apache JMeter: A Java application designed to load test functional behaviour and measure performance. Designed for testing Web Applications and has since expanded to other test functions.

  • Rest-Assured: Java DSL for easy testing of REST services.

  • Karate Labs: An open source framework for API testing, front-end UI testing, and performance testing.

  • Citrus Framework: An open source framework for Fautomated integration tests.

  • Parasoft SOAtest: A web API automation tool making use of two services, SOAP and REST, for functional, regression, and unit testing, runtime error detection, static code analysis, service virtualisation, etc.

  • Tricentis: “shift left” testing so that defects are found when they are fastest, easiest, and cheapest to fix.


  • Katalon Studio: Automation solution for API, Web, and mobile testing - Offers a free (trial) version.

  • SoapUI: End-to-end tests on REST, SOAP, & GraphQL APIs, JMS, JDBC, and other web services

    • Offers a free trial.

  • Postman API testing: APIs and service performance and health monitor - Offers a limited free version.

  • Apigee: A tool for building, managing, and securing APIs - Try it free