Every application communicates with backend APIs to serve requests. APIs act as a mediator between your front end and databases. Anything that you need from a database passes through
APIs, which validate the request, connect with a database, and provide a response to your front end. When you have so many APIs powering your applications, it becomes essential to test
them and build them correctly so that you don’t face any issues in production environments. In this article, we will discuss what load testing for Web APIs means, the benefits of doing it,
and some top tools that can help you perform the task effectively. So, first, let’s start with understanding the basics.
What is Load Testing For APIs?
API load testing is a type of testing that involves testing the backend of your applications. The backends of the system are made of various APIs that facilitate data flow and communications
between clients and servers, and that is tested to its limits in this testing process. This testing helps development teams understand the API performance under various scenarios and also
provides them insights on how things can be improved. API response times are captured for various scenarios, and this helps to understand how the application can perform and serve requests under different load conditions. Moreover, this testing can be done during the development process, whenever you push the code, or it can be done at the end, just before the deployment of the API endpoint. Having understood the basics of API performance testing, let’s find out the benefits of load- testing APIs.
Benefits of Load Testing APIs
Minimize API Downtime
API request rate testing helps you to understand how many users can concurrently request data from an API endpoint without causing any trouble to it. This helps you to find the limits of
your APIs and reduce downtime by preventive measures. When you know the limits of your APIs, you can allocate or deallocate extra infrastructure to keep the utilization metrics at safe levels. By keeping the metric at safe levels, you can surely decrease the downtime of your APIs, as most APIs only fail when they are pushed beyond their limits. Improved API Performance
By utilizing load testing services for Web APIs, you can improve API performance by many times. API development is difficult, and when a magnitude of customers consumes your APIs, it
is essential to provide great performance. With proper load testing of your web APIs, you can understand the crucial information about latency, throughput, and response times. Once you have an idea about these metrics, you can go out and optimize the performance of your API endpoints. Doing this continuously will help you completely change the performance of your APIs.
Identify Bugs Early
When your APIs are not designed by keeping best practices in mind, they are prone to errors. API load testing helps you find inefficient code blocks that are slowing down your application’s
response time or causing errors in the app. By knowing such code blocks, you can quickly change the code and take preventive measures that can steer your applications away from bugs.
Decreases Cost of Failure
Detecting issues in your APIs before shipping them to production environments is always cheaper than finding the issues in live production environments. With the load testing-infused
deployment process, you can minimize API downtime, and you can also decrease the chances of shipping the wrong code in production. By now, we have discussed the benefits of load testing and what is load testing, so you might think of carrying out this process. To do this, you need some specialized testing tools. Below is a list of popular API load-testing tools that can help you.
Top API Load Testing Tools
JMeter
Apache JMeter is among the most popular API testing tools. This testing tool is used to simulate heavy load situations on application servers, networks, and all other aspects. It is a Java-based
open-source testing tool built-in 1998. Even after 25 years, this project receives regular updates and is considered trustworthy among other load-testing tools. With a large community that develops a variety of plugins and other helpful resources, this testing tool supports multiple application types and protocols. It also comes with a powerful reporting and data analysis module that is useful in reporting the test findings. If you have a CI/CD pipeline, you can easily add this tool to the pipeline to enable automated load testing of your APIs before deployments.
Artillery
If you are familiar with NodeJS and YAML files, this is a good load-testing tool that you can use to test your web APIs. It is a CLI tool that is useful in running load tests on your API endpoints.The YAML files are quite simple, and you can easily develop a load-testing scenario in the YAML file. Artillery can be integrated into your existing CI/CD pipelines, or it can also be created as a standalone npm package that can be reused in all your projects with a simple setup. If you need to complete the testing phase quickly and export the test reports as HTML, you will love this
tool.
LoadMill
If you are new to load testing and want a simple and easy-to-use tool to find your API response times and performance, you will surely like LoadMill. It is a web service that can be used to
automate testing of your API endpoints. You can have customized data for each session, or you can provide manual input from the web service UI for your load tests. While it offers a powerful free version, you can also try out the paid version, which offers a bit more functionality for teams.
BlazeMeter
BlazeMeter is a feature-loaded testing tool that can be used independently, or it can also be combined with Jmeter. One of the unique features of this tool is that it can help you monitor your
resources directly during the test phase. It also helps you in testing your APIs with GUI in the way that your users will use the app. Moreover, it provides lots of insights in the form of screenshots, metrics, and other reports so that you don’t miss out on any findings of the testing process.
At this point, you are ready to test your web APIs and make them better continuously. If you are starting out, you should try any of the above-mentioned tools at a smaller scale first and only
then move to test all your APIs.
