Best Open Source Load Testing Tools of 2023

Jan 30, 2019
2 min read
  • #load testing
  • #javascript load testing
  • #nodejs load testing

Review and comparison of the open source Load Testing / Stress Testing Tools in 2023

Here is a list of the opensource Load Testing tools for measuring web application Load and stress capacity. These load testing tools will ensure your application’s performance in peak traffic and under extreme stress conditions.

The list includes open source Load Testing tools. Almost all of them provide a Could version which is available on paid basis and the open source version is completely free to use. You can get started with the open source version, install in your own computer or cloud. Once you decided which is the best tool for your needs, then switch to Cloud version for a production deployment.

List of Top Open Source Performance Testing Tools 2023

  • K6
  • Artillery
  • JMeter
  • Predator
  • OpenSTA
  • Fiddler
  • Locust
  • Fortio


k6 is a open source load/stress testing tool that provides an outstanding developer experience to test the performance of APIs and websites. It is a feature-rich and easy to use CLI tool with test cases written in ES5.1 JavaScript and support for HTTP/1.1, HTTP/2, and WebSocket protocols.

It provides native Pass/Fail behavior for easy automation and integration into CI pipelines. Additionally, the community has built a browser recorder and converters to facilitate the test creation process.

k6 runs on Windows, Linux, and Mac OS.

Key Features

  • Chaos testing
  • Regression testing
  • Synthetic testing
  • End-to-end web testing
  • Infrastructure testing

Official Website:

Artillery is the most advance open-source load-testing platform in the world


  • concurrency
  • requests per second
  • latency
  • throughput.
  • average response time

Key Features

  • Peak performance testing.
  • Has the ability to write custom logic and has a wide variety of NPM modules.
  • Supports protocols lik HTTP, Web Socket, Socket.IO, Kinesis, and HLS.

Official Website:


It is a Java platform application based open source load testing tool. It is primarily considered as a performance testing tool and it can also be integrated with an test plan. You can also create a functional test plan using this tool.

jMeter has the capacity to be loaded for a server or network to check on its performance and analyze its performance under different load conditions.

It also helps testing the functional performance of resources such as Servlets, Perl Scripts and JAVA objects.

It has ability to load and performance test many different applications/server/protocol types:

  • SOAP / REST Webservices
  • Database via JDBC
  • Java Objects
  • Web - HTTP, HTTPS (Java, NodeJS, PHP, ASP.NET, …)
  • Mail - SMTP(S), POP3(S) and IMAP(S)
  • TCP
  • LDAP
  • FTP
  • Native commands or shell scripts
  • Message-oriented middleware (MOM) via JMS

Highly Extensible:

  • Functions can be used to provide dynamic input to a test or provide data manipulation.
  • Scriptable Samplers (JSR223-compatible languages like Groovy and BeanShell)
  • Several load statistics may be chosen with pluggable timers.
  • Easy Continuous Integration through 3rd party Open Source libraries for Maven, Gradle and Jenkins.
  • Pluggable Samplers allow unlimited testing capabilities.
  • Data analysis and visualization plugins allow great extensibility as well as personalization.

Official Website:


Open source load testing platform: Predator is an end-to-end solution that manages the entire lifecycle of load testing APIs. It helps from creating and managing existing performance tests to running these tests on a scheduled and on-demand basis. Finally viewing the test results in a highly informative and live, built-in report.

Key Features

  • Simple, one-click installation
  • Inbuilt support for Kubernetes (helm charts)
  • Docker Engine
  • Easyly deployable in every machine that supports Docker.
  • Supports running distributed load out of the box
  • Unlimited amount of virtual users that can bombard your servers.
  • Built-in DSL feature

Allows developers to write functional and non-functional performance tests using their own business logic. Bootstrapped with a user-friendly UI alongside a simple REST API, Predator helps developers simplify their performance testing regime.

Official Website:


Open STA stands for Open System Testing Architecture. This is used by application developers for load testing and analyzing. OpenSTA is a tool with sophisticated features among all the other performance testing tools.

It has scripting capabilities and the current toolset is capable of performing heavy load testing and analysis for scripted HTTP and HTTPS.

To fina a better results, test is carried out multiple times. The output and results can be later exported for creating reports.

Key Features

  • GUI-based performance tool

System Requirement: Windows Operating System. Official Website:


Fiddler can be used with little setup, without any specialized experience of doing load testing. Fiddler is a free tool and the approach of load testing with Fiddler does not need any specialized team to prepare load test script and run it.

Fiddler is probably best described as a packet capture tool. It does many things that allow you to debug website issues.

Key Features

  • Troubleshooting issues with your web application
  • Security testing
  • Performance evaluations
  • Debugging web traffic from most computers and devices
  • Many integration features
  • Handy for finding performance bottlenecks
  • Fiddler is already a pretty popular tool among developers
  • Many use it for debugging to view the HTTP requests their computer is sending to a service or website


Helps swarm your system with millions of simultaneous users to test performance of API and websites.

Key Features

  • Define user behaviour in code
  • Distributed & scalable
  • Proven & battle tested

No need for clunky UIs or bloated XML, just write your python code and it works for you

Official Website:


Fortio is a fast, small, reusable, embeddable go library as well as a command line tool and server process. The server includes a simple web UI and REST API to trigger run and see graphical representation of the results

Graphs include

  • Single latency graph
  • min, max, avg, qps and percentiles graphs

Key Features

  • Fast
  • Small footprint
  • Reusable
  • Embeddable go library
  • Can record latency histograms and other valuable stats.