10 Best API Security Testing Tools To Use in 2024

22Jan, 2024

API security testing is of paramount importance in today’s interconnected digital landscape. APIs act as the critical infrastructure for contemporary applications, enabling smooth interaction and transfer of information among various platforms. As these interfaces play a crucial role in the functioning of web and mobile applications, ensuring their security is a fundamental aspect of safeguarding sensitive data and maintaining the integrity of digital ecosystems.

Best API security testing tools help identify and mitigate vulnerabilities that could be exploited by malicious actors to compromise data confidentiality, integrity, and availability. With the increasing prevalence of cyber threats, including API-specific attacks, such as injection and parameter manipulation, robust API security testing is essential to fortify an organization’s overall cybersecurity posture.

In an era where rapid digital transformation and cloud adoption are prevalent, API security testing is a proactive measure that safeguards not only the organization’s sensitive data but also the trust of customers and stakeholders who rely on secure and uninterrupted digital interactions. As APIs continue to be the linchpin of modern software development, prioritizing their security testing is an indispensable practice for any organization committed to maintaining a resilient and trustworthy digital presence.

In this article, we will learn about free API security testing tools and how they are used to ensure the security of API integration with applications.

Importance of Rest API Security Testing Tools

REST API security testing tools are used by agencies and leading companies to deploy software security testing services. REST API security testing tools are vital for ensuring the robustness of web services in the digital landscape. These tools help identify and rectify vulnerabilities in REST APIs, preventing potential exploits that could compromise data integrity and confidentiality.

By automating the testing process, these tools enhance efficiency and accuracy, enabling organizations to proactively address security concerns. As APIs are fundamental to modern application architecture, utilizing dedicated security testing tools is crucial for maintaining a resilient cybersecurity posture, safeguarding sensitive data, and fostering trust among users in an interconnected digital ecosystem.

Many new application security testing tools are in use today as more and more application testing companies are coming to the fore to test applications and run them on different systems. Open-source tools are the most popular today.

Also Read: Security Testing for Mobile Apps: Protecting User Data and Privacy

10 Top API Security Testing Tools in 2024

1. Postman

Postman is a multifunctional tool for API development and testing, offering capabilities for API security assessments as well. With its user-friendly interface, it allows developers to create, send, and manage HTTP requests, making it an effective choice for testing the security of REST APIs. Postman offers features like request automation and scripting for comprehensive API testing.

Key Features:

The Postman tool has many key features. The tool is used for automation and automating the scripting of test cases. The users can utilize the dynamic variables offered by the testing tool to ensure that various data scenarios are run and the app code is tested. Postman supports the management of testing environments and variables, allowing users to customize and adapt tests to different configurations easily.

Pros and Cons:

Postman has an interactive user interface and a versatile level of features that help testers find vulnerabilities in API very easily. The level of automation that Postman brings to the test environment is also an advantage. However, there are some cons, too. For example, Postman is primarily designed for testing RESTful APIs, and its support for SOAP-based services may be limited. Moreover, the learning curve of its advanced features is also steep and not easy, which is a challenge for beginners.

2. Assertible

Assertible is a web-based API testing tool designed for continuous integration and deployment. It offers automated testing, monitoring, and validation of APIs and web services. Assertible emphasizes simplicity and ease of use, with features like scheduled testing, detailed assertions, and integrations with popular CI/CD tools. It also provides real-time alerts and comprehensive reporting to ensure APIs are functioning correctly and efficiently.

Key Features:

Assertible is a tool designed for automated API testing and monitoring. Key features include easy test creation for RESTful APIs, web services, and websites, with support for various HTTP methods and authentication types. It offers flexible assertion definitions, JSON and XML validation, and environment variable support for dynamic tests. Alerting and reporting are streamlined through integrations with popular tools like Slack and GitHub. Assertible also provides robust scheduling options and detailed test result logs.

Pros and Cons:

Assertible is an API testing tool designed for automation and reliability. Pros include its user-friendly interface, robust integration options with popular CI/CD tools, and comprehensive test monitoring features. It offers detailed assertions and environment variable support for dynamic testing. However, the cons include potential limitations in complex test scenario construction and possibly a higher learning curve for beginners. Additionally, advanced features might require a paid subscription, which could be a drawback for budget-conscious users. Assertible excels in simplicity and integration but may fall short for highly complex API testing needs.

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3. Apidog

Apidog is an API documentation and testing tool designed to streamline the process of creating and maintaining API documentation. It allows developers to automatically generate documentation from code comments, ensuring that API documentation stays up-to-date with the codebase. Apidog facilitates easy sharing and collaboration on API documentation within development teams.

Key Features:

The Apidog tool is a master tool for API development and debugging. The tool is also a great tool to keep track of API documentation and automated API testing. The API automated testing suite of Apidog works seamlessly with the testing environment and checks for all kinds of vulnerabilities.

Pros and Cons:

The versatility and rich features of Apidog’s all-in-one tool have many good features and benefits. API developers are increasingly using this tool for API testing and security enhancements. However, the learning curve of the Apidog tool is not that smooth and low. If you are an experienced API testing professional, you might like the Apidog tool.

4. SoapUI

SoapUI is a leading API testing tool that simplifies the testing of web services. It supports both SOAP and RESTful APIs, providing a user-friendly interface for creating, executing, and automating test cases. SoapUI facilitates functional, security, and performance testing, making it a comprehensive solution for API quality assurance.

Key Features:

The SOAP UI testing tool is a versatile testing tool that supports the testing of SOAP and RESTful web services. The SOAP UI is also built with an intuitive interface, which is used to design and execute many effective API test cases. The SOAP UI tool is also a great tool because it supports request and response inspection to ensure the integrity of the API code.

Pros and Cons:

SoapUI offers a user-friendly interface for testing SOAP and REST APIs, supporting data-driven and security testing. It facilitates performance and regression testing, integrates seamlessly with CI/CD pipelines, and provides detailed reporting. The tool’s scripting support and extensibility via plugins enhance customization and its mock service feature aids in development.

5. Katalon Studio

Katalon Studio offers an all-encompassing testing automation tool tailored for web and mobile platforms, featuring an intuitive interface suitable for both novice and expert testers. Katalon Studio supports various testing approaches, including record-and-playback, keyword-driven testing, and scripting using Groovy.

Key Features:

1. Automation: Katalon Studio is an automated API development and testing tool that makes things easier for developers and testers.

2. Record and playback: The tool is feature-rich and has record and playback ability, which allows you to test and see the results of the testing process after recording to gather insights.

3. In-built templates: Katalon Studio has built templates that can be integrated with the test environment to maintain the test cases and increase the productivity of the testing team.

Pros and Cons:

The setup of the Katalon Studio tool is an easy and smooth process, which is a definite advantage. The built templates also help create the test cases easily and reduce testing time. However, there are some areas for improvement in this tool because it still does not support distributed testing and analysis.

6. Rest Assured

Rest Assured is a Java-based open-source library for automating and testing RESTful APIs. It simplifies the validation and testing of HTTP requests and responses, providing a concise syntax for building requests and assertions. With Rest Assured, developers can streamline API testing, validate response data, and perform various authentication methods. It is widely used in test automation frameworks, providing flexibility and ease of use for validating the behavior of RESTful services. Rest Assured supports both JSON and XML formats, making it a popular choice for API testing within Java-based test automation projects.

Key Features:

The REST Assured tool works on declarative syntax, and it is easily used for API test cases. This feature enhances the readability of the test code. The REST Assured tool also works with multiple HTTP methods, which can help in comprehensive API testing. The tool also allows the parameterization of API requests and responses, supporting data-driven testing.

Pros and Cons:

The declarative syntax, the HTTP support methods, and the response validation of the REST Assured tool are the highest pros of the tool. However, there are some disadvantages, too. For example, the learning curve, the Java dependency, and the inability to support Asynchronous API testing are all drawbacks of the REST-assured tool.

Also Read: Testing Mobile Apps in the Cloud: Benefits and Strategies


OWASP ZAP is a freely available security auditing tool, crafted to identify weaknesses in web applications. With automated scanners and various tools for both novice and expert users, ZAP helps identify and address security issues, making it an essential tool for web application security testing and penetration testing.

Key Features:

1. Intercept Proxy: The OWASP ZAP tool has the feature of Intercept Proxy, which allows the user to intercept the requests made to the API by the browser. This feature helps debug the application and screen vulnerabilities of the API code.

2. Scan Policy Control: The scan policy control feature of OWASP ZAP allows you to create scan policies for your requirements.

3. Port Scan: A port scan is an interesting feature that can perform port scans against targets to know which ports are open and are highly vulnerable. The security testing process scans the ports of a network and ensures that all ports are well protected.

Pros and Cons

OWASP ZAP is one of the open-source API security testing tools, and it is freely available. The OWASP ZAP tool is freely available for developers and testers. Moreover, there is a large active community supporting the use of OWASP ZAP, so you will get a lot of support when using the tool. However, there are some issues too that hinder the use of OWASP ZAP.

However, the steep learning curve and the resource-intensive nature of the OWASP ZAP tool are some of the drawbacks of the OWASP ZAP framework.

8. Apigee

Apigee offers an extensive API management solution as part of Google Cloud’s suite. It facilitates the design, deployment, and analytics of APIs, enhancing the development and scalability of digital services. Apigee enables organizations to create, secure, and analyze APIs, optimizing their performance and ensuring a seamless experience for developers and end-users alike.

Key Features:

1. API design and modeling: The Apigee tool is not only a testing tool but also an API design and modeling tool that meets the requirements of the business and development team.

2. API gateway: The API Gateway of the Apigee tool acts as a secure and scalable gateway for managing the traffic flow between API consumers and services.

3. Access control: The robust security measures of the API testing are strengthened with greater access and security control.

Pros and Cons

Apigee offers a robust API management platform with features like comprehensive analytics, traffic management, and developer collaboration tools. Its security measures, including OAuth and API key management, ensure secure API access.

Apigee may have a learning curve for users new to API management platforms. The broad range of features could be excessive for minor projects that require a more straightforward approach. Moreover, the cost of the platform and its resource requirements might be a consideration for certain organizations.

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9. Swagger

Swagger is an open-source tool that simplifies API development and documentation. It provides a framework for designing, building, and documenting APIs in a standardized and user-friendly way. With Swagger, developers can define API specifications using the OpenAPI Specification, enabling clear communication about endpoints, data formats, and authentication methods. The tool generates interactive documentation, allowing developers to understand, test, and consume APIs effortlessly. Swagger promotes collaboration among development teams and improves the overall efficiency of API development by providing a standardized approach to API design and documentation.

Key Features:

1. OpenAPI specification: Easily and consistently describes the RESTFul APIs and clear documentation and consistency promotions.

2. API documentation: The tool generates interactive API documentation and allows the development of test APIs directly from the documentation.

3. API testing: The tool also allows the direct testing of the coded APIs, ensuring that the APIs that integrate are highly secure and efficient.

Pros and Cons:

There are many pros of using Swagger for API testing. For example, the standardization of the test scenarios, the compilation of interactive documentation, and seamless code generation are advantages of using this API testing tool. However, other drawbacks arise from the use of Swagger, like the complex learning curve of this tool and its complexity for small projects. The resource intensiveness of the Swagger tool is also a huge drawback for developers working on small-budget projects.

10. SmartBear

SmartBear offers a suite of software development and testing tools, including API testing solutions like SoapUI and SwaggerHub. These tools streamline API development, testing, and documentation processes, ensuring the creation of reliable and well-documented APIs. SmartBear’s products are known for their user-friendly interfaces and comprehensive features, supporting efficient software development lifecycles.

Key Features:

1. API Testing: SmartBear works closely with the API framework to test its different aspects and different parts. The API testing suite screens the vulnerabilities and fixes them.

2. Data-driven testing: The data-driven testing process of SmartBear ensures that the testing process happens accurately in a data-driven manner.

3. Security testing: The security testing process of SmartBear is very effective and works well in screening security threats and fixing them.

Pros and Cons:

SmartBear provides a suite of robust API security tools that are user-friendly and feature-rich. SoapUI, SwaggerHub, and ReadyAPI offer comprehensive testing capabilities, from functional testing to performance monitoring. The cost of SmartBear tools may be a consideration for some organizations, especially smaller ones with budget constraints. The extensive feature sets of tools like ReadyAPI and SoapUI might be overwhelming for users with simpler testing needs.

These are the 10 top API security testing tools that developers and testers use today. All of these tools have different features that might overlap in certain aspects. The cost of usage might differ from tool to tool. However, it is also possible that there are open source and API testing tools free that you can use for security and performance testing. After comparing all the tools based on different factors, you should choose the right tool for your organization.

Empower Your API Security with Open Source Tools!

Based on the kind of business you have and the budget constraints, as well as considering the purpose of the project, you should choose the API testing tool. Of course, it is economical to go for free and API security testing tools open source, but it is better to go for paid models with additional advanced features. This ensures that the API is thoroughly tested and the application is highly functional.

If you are running a security testing company, you would want to choose the best API testing tool for your company. You have to pay a lot of attention to the current industry trends, the niche demands, and other aspects of the project at hand before choosing the tool of your choice. Choose the most useful and feature-rich API testing tool that you can get on your budget. Shortlist the best API testing tools and then make a final decision. You should also think of getting a multi-faceted, feature-rich API development and testing tool for the team and its projects.

Avatar for Mit Thakkar
About The Author
Digital Marketer at KiwiQA: Software Testing Service Provider Company Worldwide.

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