5 best free API security testing tools. Protecting your cloud CI/CD Pipeline

Applied Programming Interfaces (API) are an essential component of most modern programs and applications. In fact, cloud applications and mobile applications now rely heavily on APIs because they are designed to control various elements. Many large companies have hundreds or even thousands of APIs built into their infrastructure. The number of API interfaces will only increase over time. 

 It’s important to keep your website or web applications foolproof against malicious activities. What you need to do is to use some security testing tools to identify and measure the extent of security issues with your web application(s).

The primary function of security testing is to perform functional testing of a web application under observance and find as many security issues as possible that could potentially lead to hacking. All of this is done without the need to access the source code. To prevent API vulnerabilities and weaknesses, security testing is critical. API security testing ensures APIs work as designed and can only do what they are intended to. A particular tool might be the best choice for one company but not another, depending on their respective needs. Below is the list of open source API testing tools. As per cyber security course experts, although open source tools, as a rule, do not have the same support as commercial platforms, experienced developers can easily deploy them, often even for free, to increase the security level of their APIs


Taurus makes it possible to turn autonomous API testing programs into an ongoing testing process. At first look, the tool is easy to use. The user installs it, creates a configuration file and allows the tool to do its job. There are additional functions: the ability to create interactive reports, more complex scripts for testing their APIs, configure failure criteria to immediately begin to eliminate the problems detected.

Apache JMeter 

Apache JMeter (it is not surprising that it was written in Java) was originally made to test the load on web applications, but recently expanded its capabilities – now it is suitable for testing the operation of any application, program or API. Its functionality allows you to test performance on both static and dynamic resources. The tool can generate a large simulated (but realistic) load of traffic so that developers can understand how their APIs will cope during load testing. Apache JMeter does not require programming skills. It can handle many different types of applications, servers and protocols, and it supports request chaining. Tests can use CSV files to generate heavy loads of realistic traffic that put APIs under pressure.


At the tool craPI is not the most nice name (“crap” – “sucks”), but it efficiently performs its API testing functions. This is one of the few tools that can connect to the target system and use a basic set of tests with a whole set of additional functions to study root client. As per cyber security course experts, the program can do this without the need to create any new connections. Advanced API developers will be able to save a lot of time with cRAPI .


Astra mainly focuses on the transfer of a representative state (REST) of the API, which can be extremely hard because they are constantly changing. Given that the REST architecture stresses scalability when interacting between components, it can be difficult to ensure the security of the REST API over time. Astra helps solve this problem by offering integration with CI / CD-Pipeline, and by checking that the most common vulnerabilities no longer appear in the supposedly safe REST API . Astra can be used by security engineers or developers as an integral part of their process, so they can detect and patch vulnerabilities early during the development cycle.


Karate is an open source framework that combines automated API testing, performance testing and mocking into a single framework. While it is implemented in Java, it doesn’t require users to have advanced programming skills. As per cyber security course experts, test definitions can also serve as the functional documentation for the API itself. Karate can be integrated with CI/CD tools.  Additionally, tests can double as performance tests with the addition of Gatling, which verifies if server responses are as expected under load. Karate has extensive documentation, a wide range of test examples and an active user community.