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Best Api testing tools for 2023-ACCELQ
Posted On: 18 January 2023

Now that you recognize that API testing is important for your digital applications, what are the best tools for API testing? In this guide, we shall look at the 10 best tools.

Through this article, we shall cover:

What Is API testing?

Api testing-ACCELQ

More product development companies are moving towards practices like DevOps and CI/CD. And application Programming Interface (APIs) are emerging as the foundation of modern development as companies adopt the microservices architecture.

API testing is the form of software testing that checks if all APIs are working as expected. API testing is typically performed manually or through automation testing. Based on their API testing requirements, organizations can choose from the best API testing tools in the market.

To that end, let’s look at the best tools for API testing in 2023.

10 Best API Testing Tools for 2023

Here are 10 of the best API testing tools to choose from in 2023:


Rated among the leading API automation testing tools, ACCELQ enables companies to initiate API testing early in the software development process. This is crucial to detect API flaws before they become significant problems.

Moreover, ACCELQ enables continuous testing of both APIs and UI elements. With its codeless approach to test automation, here is why the ACCELQ is preferable for API automation testing:

  • Complete support for technology stack, including web applications and legacy systems
  • Unified approach towards backend API testing, including support for database systems, mainframes, and messaging queues
  • Native integration with DevOps tools like JIRA and Bamboo

2. Postman

Initially released as a Google Chrome plugin, Postman tests API services. Both Windows and Mac support Postman. Here are the best features of this open-source API testing tool:

  • User-friendly REST client
  • Supports both automated and exploratory testing
  • Compatible with Google, Mac, Linux, and Windows systems
  • Integration support for Swagger and RAML formats
  • Support for writing Boolean test cases (without command line)
  • Collection of built-in testing tools and workspaces.

With its version 7.3 (released in 2020), Postman enables users to organize API elements, including mock servers, tests, and documentation generated from API schemas.

3. Ready API

This is a popular functional testing tool that is also suitable for API testing. Among its main capabilities, this API testing tool allows testers to test SOAP and REST APIs and web services easily. Here are the main functionalities available with the free SoapUI tool:

  • Access to full source code
  • Easy creation of test cases with drag-and-drop and point-and-click features
  • Reusable script feature for reusing load test cases and security scans

Here are the main functionalities available with the paid SoapUI tool:

  • Support for native CI/CD integration and asynchronous testing
  • Data-driven testing to simulate how users interact with the APIs

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4. JMeter

Designed for load testing, JMeter is another open-source tool for functional API testing. This tool provides all the necessary functionalities for testing APIs. For example, this tool is compatible with CSV files and can integrate smoothly with Jenkins.

Here are the highlighted features of the JMeter tool:

  • Support for caching and offline replaying of test results
  • Ability to include API test cases in CI/CD pipelines
  • Compatible with both static and dynamic resources for improving test performance

5. Rest Assured

Based on the Java language, Rest Assured is among the best API testing tools for HTTP-based REST services. This tool can easily integrate with any Java-based test automation framework. Here are the main features of this testing tool:

  • Behavior-driven development (BDD) that simplifies API testing in Java
  • Seamless integration with Serenity automation framework
  • Built-in functionalities so that users don’t have to create test cases from scratch
  • A single framework that combines REST services and UI

Additionally, users don’t need to be HTTP experts to use this testing tool.

6. Karate DSL

This API testing tool allows users to create scenarios for API-based BDD tests without writing the definition steps. In essence, Karate DSL creates the definition steps itself to accelerate the API testing process. To that end, here are its main functionalities:

  • Support for UI test automation
  • Creating test cases using a Gherkin-like BDD syntax.
  • Asynchronous support for WebSocket
  • Built on top of the Cucumber JVM

Moreover, with the latest version, 1.2.0, Karate supports a host of added functionalities like redesigned HTML reports, single-call caching, and tree walking in UI testing.

7. Assertible

Popular among API developers, Assertible automates API testing at every stage, from continuous integration to delivery pipelines. Here are the main features of this API testing tool:

  • API test automation across the CI/CD pipeline
  • Easy to integrate with popular tools like GitHub, Zapier, and Slack
  • Support for validation of HTTP responses using turn-key assertions
  • Encrypted variable feature for storing passwords, tokens, and confidential data fields

8. API Fortress

API Fortress is an open-source platform for continuous API testing. With this tool, QA teams can automate both performance and functional testing. It is also highly recommended for REST and SOAP monitoring. Here are the main features of this tool:

  • User-friendly and intuitive UI for any user
  • Plug-and-play functionality for simulating API testing
  • Support for microservices, web services, SOAP, and GraphQL
  • Web-based tool using which software testers can perform API testing in any browser

9. Katalon Studio

Katalon Studio is a test automation solution for APIs, web applications, mobile apps, and Windows applications. Here are the best features of this automated API testing tool:

  • User-friendly tool interface
  • Support for SOAP requests, REST, and SSL
  • Native CI/CD integration with Jenkins, MS Azure, CircleCI, and Dockers
  • Data-driven testing for improved test coverage and reliability
  • Import functionality from Swagger, Postman, WSDL, and WADL

10. Hoppscotch

This open-source API testing tool is an ideal replacement for the Postman tool. With its minimalist UI design, Hoppscotch can generate API requests quickly, thus saving valuable development time. Here are the main features of this lightweight testing tool:

  • Full-duplex communication using a single TCP connection
  • Data transmission and receiving using the SocketIQ server
  • Support for GraphQL queries


With ACCELQ, product companies get a 360-degree approach to API testing. This codeless API Test Automation platform also integrates with UI testing. To that end, here are some reasons that make ACCELQ the best API test automation tool in the market:

  • Cloud-powered no-code test automation platform
  • API and UI test automation using a single platform
  • Support for backend SOAP and RESTful services
  • Support for messaging services, including Apache Active MQ and TIBCO

Furthermore, ACCELQ supports the following technologies:

  • MySQL and Oracle database
  • GraphQL, Tibco, and JMS
  • Microservices, including Kafka, RabbitMQ, and WebSockets

We can help you out with your API testing requirements. Sign-up for a product demo!


1. What is an API?

Short for Application Programming Interface, an API is a software intermediary layer that enables two (or more) applications to communicate with each other.

2. Is Selenium an API testing tool?

No, Selenium is not an API testing tool. However, if you are using the Selenium web browser, you can extend its framework to include API testing.

3. How is API testing done?

In essence, API testing involves making requests to one (or more) API endpoints and comparing their response with the expected results.

Nidhi Achhaa

Content Specialist at ACCELQ

Nidhi specializes in technology-based content and strives to create a unique, customized, and compelling piece with a flavor of SEO. A writer with a love for words and a storyteller at heart.

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