Best API Testing Tools for REST & SOAP Services

Top 10 API Testing tools

API testing (Application Programming Interface Testing) is a software testing type which focuses on the determination if the developed APIs meet expectations regarding the functionality, reliability, performance, and security of the application.

This article will provide the summary of the top API testing tools for REST & SOAP Services. They cover both open-source and commercial solutions that testing teams can select to suit their needs.

Promising API Testing Tools in 2021

1. SoapUI

SoapUI is a headless functional testing tool dedicated to API testing. The tool allows users to test REST and SOAP APIs and Web Services easily.
Pricing: Free – $599/year

2. Postman

Postman is a good choice for API testing for those who don’t want to deal with coding in an integrated development environment. Especially, the tool uses the same language to ensure smooth communication among developers.
Pricing: Free – From $12/user/month

3. Katalon Studio

Katalon Studio is a complete automation testing tool which provides a common environment to create and execute UI functional, API, Web, desktop and mobile app testing.
Pricing: Free – From $839/year

4. Tricentis Tosca

Tricentis Tosca is a continuous testing platform for Agile and DevOps. An array of protocols are supported: HTTP(s) JMS, AMQP, Rabbit MQ, TIBCO EMS, SOAP, REST, IBM MQ,NET TCP.
Pricing: Free trial – Contact Sales

5. Apigee

Apigee is a cross-cloud API testing tool offered by Google. It allows users to measure, test, build, and manage API gateways using other editors like Swagger.
Pricing: Free trial – Contact Sales.

The rest 5 tools could be found at Top API Testing Tools

There is no one-size-fits-all tool
It hurts, but true!

We believe the list above nominates the best solution available out there if you are planning to adopt API automation testing. However, like most of the solutions in this industry, finding the ideal-one-tool to do it all is almost impossible.

Some may find the features of the commercial players (Postman, Tricentis Tosca,…) are sufficient but the costs of ownership will be the show-stop factor. To be honest, open source solutions (Rest-Assured, Karate DSL,…) are affordable but require skilled resources and effort to implement the right frameworks. A relative balance between cost and other tools like Katalon Studio, Postman might have drawbacks to specific project types you should consider.

API Testing tools


In conclusion, API testing established its trend in automation testing, and more tools serve the growing demands of the software development teams. Finding the perfect tool is still tough, but we have the good news that you have way more choices than before. Carefully considering pros and cons of each solution — try not to be too ambitious at the early stage and trial the top 5 relevant candidates from the list above. Moreover, with the POC for these solutions, you will have a better knowledge of your project’s critical factors and fine-tune your shortlist. This approach gives you a good chance to identify the suitable tool for the current status and your requirements.

I would love to hear your feedback and let me know if you have other tools to record for the others’ reference.


More tool listing you should notice

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2 Thoughts to “Best API Testing Tools for REST & SOAP Services”

  1. Soak Testing 101 (Definition, Example & Tool)

    […] need to use an automation tool together with technical expertise since soak tests run over an extended period of time and consume […]

  2. Prasanth Koli

    Thanks for the post. It’s beautifully describeed.
    Currently are doing a POC to see if ReadyAPI can be feasible for Apigee integration testing. Appreciate your response.

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