Load testing Tools for WebSocket-based Applications

WebSocket servers are preferred for real-time connections while overcoming the restrictions of HTTP. It can give reliability and two-way communications to build real-time applications. However, before using it, you ought to test and troubleshoot it. In this article, you will find out why testing WebSocket is important and the tools you could use.

Why is WebSocket Testing Needed?

WebSocket testing; Source: Cobalt.io

A WebSocket API creates and manages WebSocket connections to the server.

So, if you test the API, you get to know any probable issues that could occur during the handshake (or connection). That’s why WebSocket testing is needed—to discover potential problems with the connection and explore how to repair them.

Technically, some things want to be checked when carrying out WebSocket testing. Some of these are:

  • Security
  • Performance
  • Status codes
  • Request and response
  • Response timings
  • Methods
  • Business logic

For example, the response time should count for your use case or deployment; with testing, you study it and try different approaches to make it better.

Similarly, the safety of WebSocket can also be assessed by testing the vulnerability of the connection. If you could intercept the link and trade the message, you would be able to recognize the issues.

Of course, all of that is possible with the assistance of testing equipment. With the right device, you could very well test WebSocket APIs and their functions before deploying them.

Benefits of WebSocket Testing

The purpose of WebSocket testing is also the benefits that you get. To explain further, let us briefly point them out.

WebSocket connection; Source: Medium

Improving Security

Whether it's WebSocket or something else, connections must always be secure. For example, the WebSocket protocol is not in charge of authorizations; however, it needs to be implemented on the application level to keep matters safe. And, when you test the connections, you know more about the implementations.

Improving Performance

While you test for everything, the performance is important too. You can take the initiative to improve your overall performance as per the test results. It will help you later if you can fine-tune the server better. Similarly, debugging the connection will provide you with better insights into how dependable it is and how well it is maintained. Reliability is noticeably important for real-time communication; the better if you improve it with testing

Challenges of WebSocket Testing

The most common challenge encountered with WebSocket technology is incompatibility with HTTP testing tools.

Another challenge includes hardware troubles, which means the situation in which you want to have multiple servers to manage the load put forward by the WebSocket connections. If you don't have sufficient servers, the connection will close, affecting the overall performance.

Not to forget, it is hard to collect response times at some point in the testing phase for websockets. Websockets are meant to stay open for communication so there is no obvious concept of response times. It is sometimes difficult to understand when it takes the message to the client, as per the user action.

To overcome all this, we need a good quality testing tool that provides us with enough insights corresponding to the real world and equips the developers for all types of situations. We'll point out a few awesome WebSockets testing equipment in conjunction so that you can try them.

Load testing Tools for WebSocket-based Applications


WebLOAD is an enterprise-grade load and performance-testing device for web applications. It is a tool of choice for firms with heavy personnel loads and complex testing needs. It allows you to perform load and stress testing on any web application by generating load from the cloud and on-premises machines.

WebLOAD; Source: Radview

WebLOAD’s strengths are its flexibility and simplicity of use, permitting you to quickly outline the tests you want with features like DOM-based recording and playback, automated correlation, and the JavaScript scripting language.

The device offers a clear analysis of your web application performance, pinpointing problems and bottlenecks that could stand in the way of fulfilling your load and response requirements.

WebLOAD supports hundreds of technologies, from enterprise applications to web protocols, and has built-in integration with Jenkins, Selenium, and lots of different tools to enable continuous load testing for DevOps.

Apache JMeter

Apache JMeter is a Java platform application. It is mainly considered a performance testing tool, and it can be integrated with the test plan. In addition to the load test plan, you may also create a functional test plan. This tool has the potential to be loaded into a server or network to test its performance and examine its working in specific situations. Initially, it was added to test web applications, but later its scope widened.

Apache JMeter; Source: GitHub

It is of amazing use in testing the purposeful performance of resources, which include servers, Perl scripts, and Java gadgets. It needs JVM 1.4 or better to run. Although it does not support WebSocket directly yet, you can use the TCP sampler to get the task done. Alternatively, you may get a plug-in that can add WebSocket support to JMeter. Needless to say, both the JMeter and WebSocket plug-ins are open-source and free to use.


Gatling; Source: Blazemeter

Gatling is a powerful tool for testing loads. Compared to WebDriver, Selenium, and TestBench, it doesn’t render the actual content; it just simulates the messages that the clients send to the server. The server doesn’t know if the test device does something with the responses, so it offers you perfectly valid numbers for your application's overall performance—on the server side. It scales very well, so you don't want a huge number of nodes to bombard your application under the test. If you need to load test your application with the most advanced communication channel, WebSockets, you can also do this with Gatling.

Pie Socket

Pie Socket; Source: Google Chrome

Pie Socket provides a managed WebSocket, used by many brands. Even if you don't use its services, you can still use its PieSocket WebSocket tester. You can input the socket.io URL to connect and test. Or you can install its browser extension to test an unsecured WebSocket.

As a web-based WebSocket testing device, you could use it to save time and get quick insights. However, it might not fit all kinds of testing use cases.


Insomnia; Source: abstracta.us

Insomnia gives a dev-friendly platform with automation and plugins that can test APIs faster. Test WebSocket APIs effectively to combine them as soon as possible into your packages. You can get started for free with the core tooling access and collaboration functions for one project. You should subscribe to its paid plans for end-to-end encryption and extra cloud project support.


Postman is a famous API platform to help you build and test APIs. You can do numerous things associated with APIs, starting from documentation to test cases.

You can open a Socket.IO request or create a new WebSocket request. Postman offers a web panel to check things, but it's strongly encouraged to apply its desktop agent for the best user experience.

Postman; Source: Stack Overflow

Whether you need to edit messages, select protocols, configure headers, or debug issues with the WebSocket connection, the log shows you all of the crucial facts to allow you to test quickly. You can also read its documentation to learn all about it.

Autobahn WebSocket

Autobahn Websocket; Source: Github

Autobahn is a completely open-source test suite to automate client and server implementations of the WebSocket protocol. It includes the essentials, compliance testing, and overall performance/limit testing. It may be run as a Docker image and used to test WebSocket clients and servers.


apic; Source: Github

Apic is a free and open-source API testing tool. It helps you to design your APIs and test them. You can also create API documentation and test reports to distribute to others. Furthermore, you get an API simulator function that will help you check or mimic the responses based on your API design.


PortSwigger; Source: Bug Zero

PortSwigger’s Burp Suite is targeted at web security testing and supports WebSockets as a part of its services. You can analyze the responses, adjust or test the messages, and rule out any vulnerabilities by scanning the WebSocket API. Unlike other tools, you can only try it for free by requesting a trial or purchasing it to use all of the features.


K6 is a specialized tool focused on load testing and identifying overall performance issues. As cited earlier, one of the challenges for WebSocket testing includes hardware limitations, such as the shortage of servers to handle the burden required for WebSocket connections.

K6; Source: Medium

So, with K6, you test the performance, locate the reliability problems, and fix them before they show up. You can test it on your local system or cloud by using the same script.


Apidog is a full-fledged API testing platform with a developer toolkit and automatic tools to generate documentation, reviews, and mock statistics to get insights.

Apidog; Source: Apidog

You can design and test WebSocket requests with no trouble. It is also well suited to Postman scripts, so you can build, test, and design the use of an aggregate of tools if you wish. Apidog is free to get started with limits to store all of the important functionalities.


With the proper testing tool, you will have whatever it takes to have reliable, stable, and speedy WebSocket connections. Of course, the tool you require will vary in your use cases. So, feel free to attempt what works well for you.

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