Which Tool Is Mostly Used For API Testing?

The Best API Testing Tools (SOAP And REST API Testing Tools)

The Best API Testing Tools (SOAP And REST API Testing Tools)

API testing is a sort of testing (software testing) that can’t be done on the front end because there isn’t a GUI- graphical user interface. API testing has mainly focused on the message layer, which includes REST APIs and SOAP Web services that can be transmitted through JMS, HTTP, MQ, and HTTPS. This is now an essential part of any Automation Testing. API testing cannot be carried out manually due to the nature of the API; therefore, we must make use of API test tools to test APIs.

Table of content:

  1. What is an API?
  2. What is API Testing?
  3. The best API testing tools
  4. Additional TOP Free and Paid API Test Tools to Consider

What is an API?

API Definition

APIs (Application Programming Interfaces) set exact rules and determinations that allow applications to interact and communicate with each other. They are in charge of laying out the types of requests that an app can make to another, as well as the three aspects of how to make those requests. That is, how to make the requests, the data format, and the practices a user must follow when making the requests. APIs permit an internet-connected application to send a request (complete with data) to a server, which will then retrieve and interpret the request. After completion, the application’s user interface receives a response containing information.

What is API Testing?

API testing is a type of software that examines how APIs were created. It looks at whether the APIs are performing as intended to guarantee that the application’s functionality, dependability, security, and application performance are not jeopardised. Moreover, API testing comprises of putting JSON or XML message payloads across MQ, HTTPS, JMS, and HTTP to test SOAP web services or REST APIs.

An API test tool enables testers to check a variety of factors, including:

  • If an API returns the intended response in the format that is expected; if it responds appropriately to edge circumstances (such as failures and unexpected inputs);
  • whether it responds to potential security threats in a secure manner;
  • The time it takes for a response to be delivered (response times).

The Best API Testing Tools

Top API Testing Tools

Top API Testing Tools (REST and SOAP API Test Tools)

ReadyAPI Logo


ReadyAPI Price: SoapUI (begins at $659 per year), LoadUI Pro (begins at $5999 per year), ServiceV Pro (begins at $1199 per year), and ReadyAPI (custom price) are the many pricing choices available with ReadyAPI. Request a quote. For a limited time, you may try the Ready API for free for 14 days.

SmartBear’s ReadyAPI platform allows you to test RESTful, SOAP, GraphQL, and other web services for functionality, security, and load. API functional testing, API security testing, API performance testing, and API and Web virtualization are all available in one simple platform. This testing platform will assist you in ensuring the quality of all web services from beginning to end. It offers a number of customizable automation solutions for incorporating API testing into your CI/CD workflow at each stage of development. You will be able to write functional API tests functional API testing) that is both comprehensive and data-driven.

Advanced Features:

  • ReadyAPI can be used in a variety of settings.
  • It comes with a Smart Assertion functionality that allows you to quickly build mass assertions against hundreds of endpoints.
  • It has native support for Git, Docker, Jenkins, Azure, and other services.
  • It also has a command-line interface for automated testing (automation tests).
  • It allows the execution of functional tests in parallel, as well as job queueing.
  • It has tools and functions for reusing functional tests and creating realistic load scenarios.
  • During testing and software development, ReadyAPI also has options for deleting dependencies (minimal dependencies).

Best For DevOps and Agile Teams benefit the most from this platform. It’s an excellent tool for RESTful, SOAP, GraphQL, and other web services’ functional, security, and load testing (load tests).



ACCELQ is a codeless API test automation tool that works in tandem with UI testing. Without writing any code, ACCELQ is the first cloud-based continuous testing tool that easily automates API and web testing. ACCELQ helps IT teams of all sizes speed up their testing by automating essential components of the lifecycle, such as test design, planning, creation, and execution.

 ACCELQ customers generally save over 70% of the cost of change and maintenance efforts in testing, solving one of the industry’s biggest pain areas. With an AI-powered core, ACCELQ brings self-healing automation and other unique features to the table. With a continuous drive to speed testing and increase quality for its clients, ACCELQ’s continuous new methodology places a strong emphasis on ser experience and design.

Key Capabilities:

  • Cloud-based API test automation with no code.
  • API and UI Test Automation in a single, easy-to-follow process.
  • Management of API Test Cases, Test Planning, Execution, and Tracking Governance
  • Management of a Dynamic Environment (dynamic resources performance testing)
  • API Test suite modification impact analysis made simple and automated.
  • For full end-to-end validation, you use Chain API Tests.
  • Planning a regression suite with requirements tracking that is linked to business processes.
  • Execution tracking and defect tracking integrations with full visibility.
  • For complete coverage, link the business process to the API it corresponds to.
  • With natural traceability, seamless CI/CD and Jira/ALM connection is made possible.
  • There is no vendor lock-in, and framework is open-source aligned (open-source framework).

Best For: With automated test design, codeless automation logic, comprehensive test management, API regression planning, and 360 trackings, ACCELQ automates API testing.

Katalon Studio Logo

Katalon Studio

Katalon Studio is a powerful and comprehensive API, Web, Desktop, and Mobile testing automation solution. Katalon Studio makes deployment simple by combining all frameworks, ALM connectors, and plugins into a single package. Katalon Studio stands out among the top API tools (tool for API testing) because it can combine UI and API/Web services for numerous systems (Windows, Mac OS, and Linux). Katalon Studio offers paid support services for small teams, corporations, and enterprises in addition to being a free solution.

Feature highlights:

  • Supports SOAP and REST requests, as well as a variety of commands and parameterization options.
  • Supports a data-driven strategy (Data-driven testing).
  • CI/CD integration is supported (integration testing).
  • Supports AssertJ, one of the most powerful assertion libraries, for creating a BDD-style fluent assertion (API-based BDD tests).
  • The Manual and Scripting modes are suitable for both beginners and specialists.
  • Katalon Studio can be used for both exploratory and automated testing.
  • Code templates that are pre-built and can be customized.
  • For immediate reference, sample projects are provided.
  • The code has auto-completion, auto-formatting, and code inspection functions.
  • UI for creating, running, and maintaining tests.

Postman Logo


Price: Postman has three pricing plans.

There is a free plan for small groups and individuals. Postman Pro plan, which is for a testing team of 50 users, is the second option plan. It will cost $8/month for each user. The Postman Enterprise is the third plan, and it may be used by any size team. The fee for this plan is $18/month per user.

It’s a platform for developing APIs. Workspaces, Collections, and Built-in Tools are the three areas of the Postman API Development Environment. You can use Postman collections to run requests, test and debug them, develop automated tests and mock APIs, document them, and monitor them. Collaboration tools will be available in the Postman workplace. It will let you share collections, define permissions, and manage participation in many workspaces for any team size. Postman is a good option for API testing for those who do not want to deal with coding in an integrated development environment utilising a similar programming language as the developer.

Note: Postman was first released as a Google Chrome extension, and it can be used to test API services.

Additional Features:

  • It is useful for automated testing.
  • Exploratory testing is aided by this person.
  • Swagger & RAML (RESTful API Modeling Language) formats are supported.
  • It encourages knowledge sharing among team members.

Best For Perfect tool for testing APIs. It contains a lot of features, is free, and has a lot of positive feedback from users.

REST-Assured Logo


This simplifies REST service testing in the Java domain. It’s a free and open-source tool program. REST-Assured accepts JSON and XML requests and responses.


  • Integrates seamlessly with the Serenity automation framework.
  • It comes with certain built-in features.
  • It understands the BDD Given/When/Then syntax.
  • It is not necessary to be an HTTP specialist to utilize the program.
Price: Free
Best for: Rest-Assured is best for testing REST API.

Swagger.io Logo


Price: Swagger Hub comes in three flavors: free, team, and enterprise plan.

 The Team plan is $30/month and has two users. You can choose from 2, 5, 10, 15, and 20 users for this plan. More users mean higher costs. The enterprise package is for groups of 25 abd above. To learn more about this package, contact the company. Swagger will assist you throughout the whole API lifetime. It will allow you to test APIs for functionality, performance, and security.

The Swagger Inspector assists developers and QAs in manually validating and exploring cloud APIs (manual testing). LoadUI Pro is used for load & performance testing. It allows you to reuse SoapUI’s functional tests.  Swagger has a lot of open source tools.

Key Features:

Swagger provides the following adv related to API:

  1. API design and development
  2. API Testing
  3. API documentation
  4. API Mocking and Virtualizations
  5. API Governance and monitoring features

Best For: Swagger is best for API designing.

JMeter Logo


Price: JMeter is free

It’s open-source software for application load and performance testing. It is cross – platform compatible. Jmeter is a protocol analyzer. This program can be used as a unit-testing tool for JDBC database connections by developers. Its architecture is based on plugins. Jmeter has the ability to generate test data. It has a command-line mode, which is useful for Java-compatible operating systems.


  • It will enable you to work with a variety of programming languages.
  • Many different apps, servers, and protocols are subjected to load and performance testing.
  • It supports variable parameterization and assertions.
  • It gives you the option of replaying test findings/test results.
  • Jmeter additionally supports configuration variables and a variety of reports.
  • Per-thread cookies are supported.

Best For: JMeter is best for load testing and performance testing of web applications.

Karate DSL Logo

Karate DSL

Price: Free

It’s an open-source API testing framework. The cucumber library serves as the foundation for the Karate framework. A tester can use this tool to write tests in a domain-specific language to test web services. Intuit has published this tool that is specifically built for automated API testing. A programming language is not required to use this tool. However, having a basic understanding of HTTP, JSON, XML, XPath, and JsonPath will be beneficial.


  • Parallel execution in many threads is supported.
  • It allows you to change configurations.
  • The creation of reports.
  • Payload-data can be reused for API testing.

Best For: It lets you write tests in any language that supports HTTP, JSON, or XML.

Airborne Logo


Price: Airborne is free

This is a free and open-source API testing framework. Airbone is an RSpec-driven Ruby framework. There is no user interface for this tool. It simply gives a text file in which to write the code.


  • It can operate with APIs created in Ruby on Rails.
  • To use Airborne, you must have a basic understanding of RSpec
  • and Ruby.
  • It’s compatible with Rack-based apps.

Pyresttest Logo


Price: Users can make a donation by signing up for a GitHub account.

It’s a RESTful API testing tool written in Python. It can also be used for micro-benchmarking. JSON config files are supported for testing. Python allows for further customization of the tool.


  • The creation of test scenarios by using technologies like generate/extract/validate.
  • For failed results, return exit codes.
  • It’s simple to deploy on the server because of its minimum requirements, which is useful for smoke testing.
  • There is no need for a code.

Pyresttest is best for RESTful APIs.

Apigee Logo


Apigee has four pricing options/pricing plans: Evaluation (free), Team ($500 per month), Business ($2500 per month), and Enterprise ($2500 per month) (Contact them). Apigee tool also comes with a free trial. Apigee is a platform for managing APIs across many clouds.

For all APIs, it provides security and governance policies. The utility makes it simple to create API proxies by using the open API specification. You can design, secure, analyze, and grow APIs from anywhere using this tool.


  • It has a developer portal that’s customizable.
  • It is compatible with Node.js.
  • Superior features such as Apigee Sense advanced security, distributed network for low latency, monetization for innovative business models, and API traffic isolation are included in the Enterprise plan.
  • IP whitelisting, Java & Python callouts, and distributed traffic management are all included in the Business plan.
  • API analytics, Web service callouts, and advanced controls such as security, mediation, and protocol are included in the Team plan.

Best For API development.

Additional TOP Free and Paid API Test Tools to Consider


Parasoft, an API Testing tool, assists in the creation of automated test cases that can be reused and readily maintained, reducing the amount of time spent on regression testing. It offers a very user-friendly UI and supports end-to-end testing.

Supports a variety of platforms, including Java, C, C++, and.NET. This is one of the most highly regarded API automation testing tools. Because it’s a paid product, you’ll need to purchase a license and then install it before you can use it. By generating codeless API test scenarios from hand recordings, Parasoft SOAtest automates the continuous testing of complex systems.

Official Website: Parasoft

vREST Logo


An automated REST API testing tool that can be used on the web, mobile, or desktop. Its record and replay feature simplifies the construction of test cases. This tool can be used to test apps that are hosted locally, on an intranet, or on the web. Support for Jira and Jenkins integration, as well as imports from Swagger and Postman, are among its strong points. 

Mock Server Functionality in vREST can be used to generate API mocks. Using fake HTTP requests, the user can immediately begin developing the frontend.

HttpMaster Logo


If you’re searching for an ideal tool that can help with both website and API testing, HttpMaster is the way to go. Other capabilities include the ability to declare global parameters and the ability for the user to implement data response validation checks utilizing the wide number of validation types supported.

Runscope Logo


A great tool for keeping track of and testing APIs. This tool can be used to validate API data and ensure that the proper data is returned. This tool has a feature that allows you to track and inform you if an API transaction fails. If your application requires payment validation, this tool could be a suitable fit.

Chakram Logo


End-to-end tests on JSON REST endpoints are supported by this tool. Third-party API testing is also supported by this tool. If you need to test APIs that are still in development, this tool can be really useful. The Mocha testing framework is used to create this.

Rapise Logo


This tool has a long number of features that cater to all types of testing requirements, including API testing. This allows for the testing of both SOAP and REST web services. It also permits testing of several types of DLL APIs, ranging from managed (i.e., developed using the.NET framework) to unmanaged (written with native Intel x86 codes).

API Inspector Logo

API Inspector

API Inspector is an Apiary tool that allows users to monitor APIs throughout the design phase by capturing both request and response and allowing them to be viewed by the user. Apiary.io, often known as Apiary editor, is a website that allows users to create API blueprint(s).

SOAPSonar Logo


SOAPSonar is a service and API testing tool owned by Crosscheck Network, one of the major API tool developers. Testing can be done using a powerful tool that simulates HTTPS, REST, SOAP, XML, and JSON. CloudPort Enterprise, which is mostly used for Service and API Emulation, and Forum Sentry, a tool for safeguarding APIs, are two more solutions from the same company.

API Science Logo

API Science

API Science, an amazing API monitoring tool, has a functionality that allows you to monitor both internal and external APIs. This utility notifies the user if any API goes down, allowing them to take the necessary steps to restore service. Excellent API diagnostics, a user-friendly dashboard, an alarm and notification system, powerful reporting, and support for JSON, REST, XML, and Oauth are all important aspects.

Relevant Information on API testing

API testing Relevant Information

  • RedwoodHQ is an open-source API testing tool for testing SOAP/REST APIs. It supports a variety of languages, including Java/Groovy, Python, and C#.
  • Tricentis’ Tosca is a model-based API automation testing solution that also provides API testing.
  • Subject7 supports both REST and SOAP API testing, as well as end-to-end and database testing. With a simple and easy-to-use interface, Subject7 makes it simple to scale and conduct complicated API tests.
  • Quick and Easy Test Creation is available in SOAP UI: Complicated tasks (such as working with JSON and XML) become simple with point-and-click and drag-and-drop functionality.
  • Ping-API is an API testing tool that allows you to test your APIs by writing test scripts in JavaScript and CoffeeScript. It is one of the greatest api testing tools available, allowing you to inspect HTTP API calls with all request and response data. Any failures are communicated to the user by email, Slack, or Hipchat.
  • API testing becomes more crucial in Agile development as development cycles become shorter, putting more demand on automated testing.
  • WebInject is another open-source solution for automated testing of web apps and web services.
  • Tricentis Tosca is a continuous testing platform meant for Agile and DevOps.
  • JMeter is a widely used performance testing tool, which is effectively utilized to load test web and mobile applications and measure their performance.
  • Penetration testing, security testing and fuzz testing are the components of the security auditing process aimed at testing an API for vulnerabilities from external threats.
  • Using Rest-Assured users can integrate your UI and REST tests in one framework that generates awesome reports.
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