The purpose of performance testing tools is to simulate what would happen to an application under different real-world experiences. One of the most popular forms of performance testing is load testing. In load testing, we are testing the behavior of a system when different size loads are placed upon it and seeing the responses. Two of the most popular tools are K6 and JMeter. Both are open source and free for you to download and start using today
Where JMeter Shines
- JMeter has a GUI for its application to help its users navigate the application.K6 has a GUI too, but it is in its cloud version which is not free.
- JMeter has been around for 20+ years and has a large user community and has been improving steadily as a tool in that time, whereas K6 is less than 10 years old
- Because of how long JMeter has been around, it by default has more 3rd party materials
- Built-in reports including a HTML report that can be generated
- Supports more protocols than K6
Where K6 Shines
- K6 right out of the box has most of the features that you will need for your load tests without the requirements of plugins like JMeter.
- K6 was built with performance in mind whereas JMeter is built on Java. This means JMeter may require more resources from your machine to run larger tests and can lead to errors.
- K6 is easy to install and set up via the command line without any external dependencies. whereas in JMeter you have dependencies such as Java that must be installed prior.
- K6 supports the creation of thresholds at the test level such as failing the test if 80% of the response time is greater than 10 secs
- K6 allows you more threads and virtual users that can be run for your tests with a lower resource cost
K6 and JMeter are both really good testing tools but some key deciding factors that you may want to consider are, are you comfortable using the CLI or would you rather have a GUI? Will you be working by yourself or with a team that will also need to update and manage your tests? Will you be using older protocols that may not be supported by K6? Do you have the resources on your machine to run large JMeter tests or is your setup better suited for K6? Once you can answer these you can make a decision about what test is best for you.