Over time, limitations were found with the programming languages responsible for creating web applications, leading to the development of WebAssembly (WASM). You can leverage WASM to create applications for web browsers using other high-level programming languages than those traditionally used for web development. As a result, developers can now build cloud-native applications that can work more efficiently with Kubernetes and other cloud-native technologies.

Throughout this piece, we will explore how you can leverage WASM for improved performance in Kubernetes to create efficient, scalable applications.

What is WebAssembly?

WebAssembly is a binary instruction format executed in modern-day web browsers for stack-based virtual machines. It standardizes the fast execution of code compiled from high-level languages other than Javascript, the primary language used for web development. As a result, developers can use languages like C, C++, Rust, etc., to build applications that can run on web browsers.

What is WebAssembly?

The benefits of WebAssembly for web development

  • Improved development of applications: With the use of WASM, developers can build faster and more efficient web applications using languages other than JavaScript. In addition, WASM provides an ahead-of-time compilation of codes, resulting in quicker execution of WASM code than interpreted code. This improves performance for applications that process large amounts of data or are CPU-intensive.
  • Interoperability:WASM has the ability to interact with Javascript and Document Object Models (DOM) to access web APIs. It allows developers to leverage existing technologies while developing applications using various programming languages.
  • Reusability:With WASM, developers can reuse and take advantage of existing codes and libraries as its modules can be used in different web environments. In addition, the reusability of codes reduces the time needed for building applications as developers can reuse tested and proven codes.
  • Security: An extra layer of security is provided with WASM by isolating the untrusted codes as it runs in a sandboxed environment.

How to use WebAssembly with Kubernetes?

Besides web browsers, WASM can be used in a standalone environment like Kubernetes. It is fairly straightforward and can be done in several simple steps. They are listed below:

  1. To use WASM with Kubernetes, you must compile your WASM code into a WASM binary. Online tools like Emscripten can help you achieve this, or you can check the native WASM support of your preferred programming language.
  2. The next step would be to build a container image that includes the WASM binary and all its dependencies. This image can then be utilized with tools such as Containerd or Docker for further management.
  3. Now you have the container image; it's time to deploy the application using Kubernetes. For this, you must create a deployment resource that will specify the container image and the number of replicas you want to run.
  4. After deploying, you have to create a service resource that exposes the deployment to external traffic. You can use the Kubernetes command-line tool, kubectl, to create the deployment or the service resource on your cluster.

using WebAssembly with Kubernetes

You can manage the availability and networking of your application at scale with built-in Kubernetes features like autoscaling and load balancing. In addition, taking advantage of WASM runtimes like Wasmtime can help you run WASM directly within a Kubernetes cluster without wrapping it in a traditional container image.

Tools and applications using WASM are making roads to the Civo Kubernetes ecosystem. Recently, Fermyon has been added to the Civo marketplace. This is a hosting platform for Spin applications and other WASM workloads. You can install Fermyon on Civo Kubernetes using Terraform. The detailed guide for installing Fermyon can be found here.

Best practices for using WebAssembly in a Kubernetes environment

  • Using smaller WebAssembly modules: WASM modules are compiled ahead of time; hence, they can be larger in size than Javascript modules. This can have a negative impact on the performance of an application. To mitigate this, it is recommended to use smaller WASM modules that only contain the code needed for a specific task.
  • Monitoring application performance: WASM can enhance an application's development but requires more resources than Javascript. Hence, while using WASM, it is essential to monitor the performance of an application. Tools like Prometheus, Jaeger, and Graffana can help monitor your WASM modules' CPU and memory usage. Monitoring will ensure modules are not overloading your system.
  • Using WebAssembly for CPU-intensive tasks: WASM performs excellently in applications that are made for CPU-intensive tasks like image processing or data analysis. Therefore, consider using WASM if you have an application that performs CPU-intensive tasks.
  • Multilanguage strategy: Although WASM is a powerful tool, it is not an answer to everything. Choosing the right tool for the job is vital while building an application. So, consider using a mixture of JavaScript and WASM while building your application.
  • Using persistent volumes for WebAssembly modules:Storing large and frequently changing WASM modules in persistent volumes can enhance the performance of an application. Saving the modules in this way eliminates the need to load them from the network every time they are used, thus improving performance.

Common pitfalls to avoid when using WebAssembly with Kubernetes

  • Choosing the wrong container runtime: While using WASM with Kubernetes, it is better to choose an optimized container runtime for WASM. Runtimes, such as Wasmtime and Wasmer, are explicitly optimized for WASM and can perform better.
  • Failing to optimize the size of WASM modules: Deploying an application to Kubernetes with large WASM modules can be a problem because downloading and deploying those large modules will take a lot of time. This issue can be avoided if you can optimize the size of the modules as much as possible.
  • Failing in proper optimization of code: Proper optimization of WASM code will ensure your application's smooth and efficient performance. Minimizing the number of memory allocations and cutting down on expensive operations along with others will help achieve optimal performance.
  • Failing in proper testing of the WASM modules: Thorough testing of WASM modules will ensure the stability and reliability of your application. By testing the modules in different web browsers and operating systems, it will ensure compatibility and consistency across different environments.
  • Non-consideration of security: As WASM has its own security and is a powerful technology, it is crucial to consider security while using it in a Kubernetes environment. Proper handling of errors can prevent potential vulnerabilities, along with cleaning and validating data through filtering and encoding.


WebAssembly (WASM) allows for the development of web applications with programming languages other than JavaScript, leading to faster execution of code and improved development overall. The reusability of code and interoperability with web APIs are among the many benefits developers can take advantage of when using WASM.

When used alongside Kubernetes, it is a powerful combination to develop and deploy an application. To optimize performance, it is recommended to use smaller WASM modules in Kubernetes, monitor the memory usage of the modules, and use WASM-optimized container runtimes. Additionally, it's important to thoroughly test and optimize the code and size of WASM modules to avoid any performance issues. While powerful, WASM can be used alongside JavaScript to create efficient and high-performing applications.

As WASM is a relatively new technology, developers will continue building new applications with it that are deployable in Kubernetes. Accessing Kubernetes is much easier with Civo. Sign up by clicking here and get free credits up to $250.