API Security Testing

by | Jan 30, 2023

API Security Testing

Application Programming Interface plays an important role in allowing organizations to create new and innovative services. Since APIs have become an integral part of our modern digital world, ensuring their security is also important for the sustainability of all our connected innovations. In fact, Application Programming Interface security testing is the most effective method to ensure the technical robustness of our APIs against attacks and exposure to vulnerabilities. This blog comprehensively aims to explain what is API Security Testing, Which are the top tools used, and also their importance.

What is API Security Testing?

API security testing involves testing API for any potential vulnerabilities that can compromise the functioning of the API which includes the exposure of sensitive data in it. It is mostly done by sending requests or inputs to an API and examining its response to identify unusual behaviors or weaknesses in technical efficiency.

How Can You Perform Security Testing on API?

API testing can be manual or automated!

Automated security testing tools send various requests and inputs to the API and analyze the output or responses.
It also examines authentication, encryption, access controls, and other characteristics of the API.

Manual security testing involves checking the security and technical robustness of code configurations, tools, process, and procedures that makes the API.

This also includes reviewing the documentation, analyzing the request and response structures, and more.

In summary, API security testing is not a once-in-a-cycle process but an ongoing process.

Top 7 API Security Testing Tools

Security testing is not an easy process to carry out. Therefore automating and improving its efficiency with popular security scanning tools and methods. are important. In fact, there are many tools that can improve the efficiency of your testing job. Some of the Top 7 API Security testing tools which can help to detect API Security Risks are as follows :

OWASP ZAP (Zed Attack Proxy)

OWASP ZAP (Zed Attack Proxy) is a comprehensive and highly-regarded open-source web application security scanner that offers a wealth of features to help secure your APIs. Its robust capabilities include API scanning, manual testing, thorough security assessments, advanced attack simulation, replay functionality, and fuzz testing.

Burp Suite

It is a comprehensive software platform that facilitates application programming interface testing by allowing proxying, manual testing, scanning, and development of custom plugins for security testing and also helps in generating detailed API test reports


JMeter is an open-source tool that can test security and monitor the performance of APIs by helping with Load testing, Parameterized Testing, Authentication Testing Custom Scripting, and reporting API security test


Postman is a popular tool for testing and documenting APIs. It tests for common vulnerabilities such as SQL injection, Cross-site scripting XSS, and Cross-site request forgery CSRF. It can also test the proper implementation of authentication and authorization mechanisms.



SoapUI is an open-source tool for functional testing, security testing, and load testing of SOAP and REST APIs. It is a very user-friendly tool that helps with creating, executing, and analyzing API tests. It is a popular tool for testing for many organizations-big and small who are dependent on API in many ways.


Fiddler is a free, open-source web debugging proxy that helps to test the security of APIs and other web-based applications. The Fiddler tool helps you debug web applications by capturing network traffic between the Internet and test computers. The tool enables you to inspect incoming and outgoing data to monitor and modify requests and responses before the browser receives them.


AppScan is a security testing tool developed by IBM to track vulnerabilities in APIs. The tool checks for threats in underlying web applications and API code. And also identifies threats in API design and configuration. Moreover, APIScan integrates with other DevOps and security products and helps to implement better security testing measures for APIs.

These are just a few examples of the many best tools that are available for security testing. Depending on the specific needs of your organization, you may find that one tool or another is better suited to your use case.

Importance of API Security Testing

API security testing is important to identify API vulnerabilities. It makes developers proactive in securing APIs from attacks that have the potential to hugely cost an organization. Here are some of the ways it helps

  • Identifies and mitigates potential security risks.
  • And protects against data breaches and security incidents.
  • Ensures confidentiality, integrity, and availability of data and systems.
  • Also helps to comply with industry regulations and standards.
  • In fact, it can increase the overall security posture of the organization.

The most common vulnerabilities faced by APIs include SQL injection, broken authentication, sensitive data exposure, XML external entity, broken object level Authorization, misuse of API keys, and Lack of rate limiting. It’s important to note that this list is not exhaustive, and new vulnerabilities and attack vectors may emerge over time.

Which is the best method for API security testing?

API security testing embraces a variety of methods, including penetration testing, vulnerability scanning, and runtime security testing. These testing techniques all have different goals and are used to find various vulnerabilities. As a result, the best strategy for ensuring thorough security testing coverage is usually to combine different testing approaches.


API security testing is a process that is used to check the security of an API and identify any vulnerabilities and weaknesses. It is very much useful to ensure security for applications that are using API.  The idea behind API testing is to imitate a model of a bug and mimic attacks to check the efficiency of the API in terms of its technical feasibility and security against attacks. Some of the best API security testing tools are OWASP ZAP (Zed Attack Proxy), Burp Suite, Jmeter, Postman, SoapUI, Fiddler, and Appscan.


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