API testing with JMeter – Advantages

When a QA Analyst tests API services, the first tool they’ll use is Postman, a well-known application for these tasks. At least, that happened to me and many other QA analysts I know. My first encounter with JMeter was working on performance testing (volume and stress testing on a website). This type has many qualities that make your tests easier. It works by simulating a browser and giving you many results and a short period.

Are we testing the UI or are we testing the API through the UI? Find all the answers in our blog post on API Testing.

After a long time working on API testing using Postman, I decided to give JMeter a try. And honestly, I have to say: no regrets, I should have tried it earlier!  JMeter is a flexible tool, and we can configure it ourselves to fit our project goals.

JMeter is open-source software originally designed for load testing but has since expanded to other functions. There are a lot of tutorials and troubleshooting articles on the internet that can help us anytime.

In my opinion, these are the functionalities on JMeter, which makes it a very powerful tool for API testing:

1.- It can simplify the action to access a website with tokens or special keys, saving us time and making testing more productive. Configuring a Simple Controller with a Regular Expression Extractor (a JMeter functionality for extracting a key or token from the response) helps perform your test cases quickly.

2.- We can send requests to the server with parameters, as well as a browser.  The server should receive requests with information, and each request depends on the data we send to it, so sending different parameters to the server makes you receive different answers.

And you can add information in JSON format too.

3.- You can verify the response status of a server. Running your test, the server will return the status code, and JMeter will compare it with the value in the response assertion and show if the test has passed.

4.- You can use timers and delays to get close to real load conditions (Constant Timer and Beanshell Timer are one of the most popular ones).

5.- The testing results are very easy to look at;  you can choose between graphics, tables, or register archives.

Besides the functionalities I reviewed in this post, there are many other very interesting plugins to discover.  Hope to talk to you about them next time.

Are we testing the UI or are we testing the API through the UI? Find all the answers in our blog post on API Testing.

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