Top 8 REST API testing tools in 2025

Most of the web apps we use have a client-server architecture. The app itself is a client (frontend), and you need it to communicate with a server (backend) to transfer data. This communication is possible using HTTP requests since the client sends HTTP requests to the server.

Here is where REST APIs show up.

REST API: what is it?

In simple words, a REST API (REST stands for “representational state transfer”) is a set of regulations on how the communication between a client and a server must be realized. REST APIs contribute to the seamless communication between different services. 

Every server has endpoints that look outside. When a client communicates with a server, it happens via the endpoints. A REST API works like a CRUD when working with a database located on the server. Here are the steps: 

1. A client sends an HTTP GET, POST, PUT, or DELETE request to a server in an appropriate format.
2. The server receives the HTTP request and turns to the database.
3. The server forms a query to pull the needed data from the database.
4. The server sends the requested data to the client.

REST APIs represent a flexible and scalable way of integrating one web service with another one. Since REST APIs are standardized, you don’t have to format your data in any specific way. 

REST API advantages

The use of REST APIs has several essential advantages. Among them are:

• REST APIs are easy to understand. As said above, REST uses standard HTTP methods: GET, POST, PUT, and DELETE when communicating with a server. Thanks to a REST architecture, developers can simply display the needed data on the client-side, and manipulate it on the server-side.‍
• A client and a server are separated. The REST API architecture implies the separation of a UI from a client and a server. Due to this, a user interface can be easily moved to other platforms.‍
• REST APIs are scalable. Since a client and a server are isolated from one another, they can be scaled independently. Making changes to the database and tracking them doesn’t require too much effort.‍
• REST APIs ensure that the data is cacheable. To improve the overall performance, a REST API contributes to the cacheability of the stored data. The resources both on the client-side and the server-side are cacheable.

Top 8 API and REST API testing tools to try in 2022

Despite all the advantages RESTful web services have, it’s still important to make sure they are not vulnerable. Manual API testing is too complex and time-consuming. Below, we've compiled the list of the best and most commonly used API testing clients to look into to test your REST API in 2022.

#1. HTTPie

HTTPie is an API testing client in Python. It’s tailored for REST APIs testing and debugging. HTTPie makes the communication with HTTP servers, REST APIs, and web services seamless. You don’t need to have any specific skills to start using HTTPie.

Key features:

• User-friendly.
• Intuitive. 
• Web and desktop versions.
• Easy to learn.
• JSON support.

#2. Postman REST Client

Postman REST Client is an API testing platform for sending requests, viewing and inspecting responses, debugging REST APIs, etc. This API testing tool allows you to send HTTP requests to a development server. 

Key features:

• REST, SOAP, and GraphQL support.
• Data visualization.
• Built-in variables support.
• Multiple protocols support.

#3. curl

Curl is an Open Source command-line tool used to transfer data with URLs to/from a server. You can use curl to send HTTP POST, PUT, and DELETE requests to a development server, and test your REST API.

Key features:

• HTTP, HTTPS, IMAPS, LDAP, FTP, DICT, RTSP, POP3, and other protocols support.
• Open Source, with a large number of contributors.
• An ability to add and execute a script with batch requests.

#4. Swagger

Swagger is an Open Source API development, design, and testing platform for different team sizes. Swagger uses the OpenAPI Specification – the industry standard for designing REST APIs.

Key features:

• Full cycle of REST API development support including design, documenting, and testing.
• OpenAPI Specification.
• An ability to create and share OpenAPI definitions.
• API mocking.
• Access control.

#5. Katalon Studio

Katalon Studio is an all-in-one solution aimed at automating web, API, mobile, and desktop testing. It allows you to create and send HTTP requests to a development server.

Key features:

• Easy test generation.
• UI elements storage ensuring reusability.
• No coding skills.
• Seamless integration into your existing ecosystem.
• Integration with Jenkins, Bamboo, Azure, and CircleCI.

#6. SoapUI

SoapUI is an API testing tool aimed at making it possible for you to achieve a better API quality. It allows you to easily create and perform REST, SOAP, GraphQL, and other web services testing.

Key features:

• Open Source.
• Integration with the existing CI/CD pipeline.
• Drag-n-drop method.
• REST, SOAP, JMS, and other requests support.
• A comprehensive knowledge base.

#7. REST-assured

REST-assured is an Open Source tool to test REST APIs in Java. The tool is especially loved by Java developers who can test web services easily and fast via it.

Key features:

• Clear and understandable tests.
• Various types of XML and JSON requests.
• Integration with the Serenity Automation Framework.

#8. Apigee

Apigee is an API testing tool used for designing, measuring performance, and scaling REST APIs. This testing platform offers can help you ensure seamless digital experiences for back-end services and serverless stacks.

Key features:

• Full API development lifecycle capabilities.
• A flexible developer portal.
• High-level security and privacy.
• Great performance and reliability.

Instead of conclusion: A low-code approach to API testing

The quantity of APIs is rising together with the vulnerabilities that can damage cloud services. That’s why regular REST API testing is vital to ensure a proper security level. 

In addition to the traditional API testing tools, low-code platforms have already joined the game. They allow even non-tech people to create API tests visually to test the functionality you need. Adopting continuous API testing is a good practice to be able to detect API errors before someone else outside your team does it. 

Thanks to low-code, API testing is not something only developers and professional QAs can cope with. More people in your company can now take part in REST API testing process, thus relieving your development team from the need to distract from more critical tasks that add value to your business.

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