Gatling VS K6

in DevOps


Gatling and K6 are performance load testing tools, and they are both open source, easy to run, and powerful testing tools. While K6 is the more commonly used one, Gatling has gained popularity also. We have compared the features, stats, pros, and cons of both tools in this article.

    Load testing tools are used in engineering environments to measure the capacity of the software. With a load testing tool, you can check the response of a system when a predefined workload is assigned to it. It is a type of performance test done on software that discloses the potential problems the software would experience when handling large numbers of users.

    In addition to finding leaking points, performance testing helps ensure users' satisfaction, improve the scalability of the software and prepare the builders for unexpected traffic. We'll be comparing the two open source testing tools in this article.


    Gatling dashboard. Source: Gatling dashboard. Source:

    Gatling was released in January 2012 and is an open source load testing tool written in Scala. Gatling has gained popularity in testing environments even though it operates with a relatively obscure language while running. This is due to features that make it relatively easy to use and adopt.

    Compared to other testing tools, Gatling is considered a powerful load testing tool. A significant factor contributing to this rating is its architecture. The Gatling tool uses the Akka toolkit, and this adds to its advanced architecture. Akka allows Gatling to use a multithreading allocation pattern for its users, allowing its save CPU and RAM to accommodate more users. Generally, Gatling performs better than other testing tools.

    Users can run Gatling in both local machines and the cloud, and it uses domain language that people with low technical knowledge can interpret. This is good because when testing is done across different teams, everyone involved can read up to quickly get up to speed on what has been done by reading the text related to testing creation.

    Gatling is run on the command line, and this makes continuous integration easier. Developers can create performance tests written as source codes and keep track of changes made and all the history of the test build. With tests as code, developers can store their code in version control systems. Integrating with monitoring tools like the Gatling executor Taurus or going ahead with the Gatling frontline would provide test results in real-time. Developers wouldn't have to wait till the end of the test to figure out what is wrong or possible problems. You can also achieve this by integrating Gatling with open source monitoring tools.

    Because you need to learn Scala to use Gatling, this load testing tool has a higher entry barrier than its alternatives. Learning this is however a high effort, high reward feature as users who take their time to learn have many positive opinions on the tool. Testing non-supported protocols on Gatling is also not so reliable because the software has only been developed to support few protocols.

    Gatling has over 100 thousand companies using it. This includes Craftbase, Peloton, Immowelt Group,, Queue-it.


    K6 dashboard. Source: K6 dashboard. Source:

    K6 was previously called load impact and is an open source load testing tool used by developers to check software efficiency. It is available on Github, where it has received 11000 stars from community members. It is a popular tool among developers due to its easy-to-use framework. K6 uses Go and Javascript languages in its architecture. Since Javascript is a popular language among developers, it's no surprise that K6 is a widely used tool in testing.

    Besides being written in Javascript, K6 has many features that make it a popular and trusted testing tool among developers with little knowledge of Javascript.

    K6 has a goal-oriented testing mode, and users can define goals using Thresholds when building their tests. Continuous integration is a priority for it as developers find this feature very useful. It is run on the command line and can be integrated into CI pipelines like Azure, Github, and Jenkins, among others. It is relatively easy to use compared with other testing tools, and the Javascript language makes entry into it more effortless.

    Result visualization with K6 can also be done by integrating tools of the developers' choice. Tools like Apache kafta, K6 Cloud, new relics, and a couple of other tools can be used with the K6 console to visualize results.

    Creating a load test from a user session is a supported mode on K6. Users need to create a HAR file either from the user session or the browser, and the K6 recorder will generate the test automatically. When integrating into a load testing website, this feature comes in handy. Users can equally create test scripts from other converters like the Jmeter converter and Open API converter.

    For disadvantages, users are required to bundle and transpile before using npm packages.

    K6 has over 20 integrations that make it easy for users to add it to their workflow. Integrations include Graph QL, Apache Kafka, Azure, Datadog, Grafana e.t.c. K6 has a commercial SaaS product called the K6 cloud that accompanies the open source tool. They also have a community that provides support to its users and a forum for them to ask all K6 related questions.

    Comparing the cons and stats of both tools

    To summarize the main differences between Gatling and K6, we created this table:

    Gatling K6
    Open-source testing tool Open-source testing tool
    It loads its tests as code It is a code first tool
    The total number of stars it has received in Github is 5.3k The total number of stars received in GitHub is 14,000
    It has a total of 1400 stack overflow questions It has a total of 171 stack overflow questions
    Gatling has 1100 GitHub forks K6 has 700 forks on Github
    Gatling can be run in a cluster mode Works well in a CI workflow
    Gatling has had 12 releases K6 has had 37 releases
    It is a scala based tool Tests scripts in K6 are written in Javascript
    It provides a detailed report for all tests run It provides a detailed report for all tests
    Easy to use and interpret Easy to use

    Alternatives to K6 and Gatling

    Alternative load testing tools to Gatling and K6 include Selenium, Blazemeter, Locust, Cucumber, amongst others. You can read up on our check our top 10 HTTPS Benchmarking and Load testing tools/.

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