Intern Software Engineer - Compilers (WebAssembly) - Amsterdam [two positions](Remote)

Do you want to work at the cutting edge of browser technologies? Are you interested in working on Development Tools?

Join our engineering team, where you will be working on the next generation of compilers and virtual machines that target HTML5/WebAssembly, contributing to our vision of bringing any application to the Web. We are looking for an enthusiastic developer-to-be, interested in joining a very dynamic and rapidly growing specialist software company developing WebAssembly solutions.

This is a full-time paid internship position based in Amsterdam (near Amstel station), Netherlands, with a duration of 6 months, starting in April/May 2026.

What we offer

• Flexibility and part-remote work is guaranteed to all employees.
• Join a team of incredibly talented minds, in a position with plenty of opportunities for personal and professional growth.
• Get to work on challenging, complex and stimulating projects.
• You will work with our CTO and other developers, and get 1‑1 tutoring and guidance from the rest of the team. We have very minimal overhead, a flat structure, and we prefer to get to work rather than spend hours in meetings.
• We offer high flexibility, family‑friendly arrangements, and actively promote a good work‑life balance.
• This is a paid internship, you'll be compensated at 1600 EUR per month.

What you will be doing:

Project 1: Improve CheerpJ JIT

CheerpJ ( is a Java Virtual Machine that runs fully in the browser. It can run large‑scale Java applications and applets with no modifications, including code that uses multi‑threading, reflection and other advanced Java features. CheerpJ uses its sophisticated Just‑In‑Time compiler to build JavaScript functions out of the original Java bytecode. Your task will be to implement some self‑contained improvements to the JIT.

• Familiarize yourself with CheerpJ
• Learn about Just‑In‑Time compilation
• Add new features to the JIT

Project 2: Create new testing infrastructure using Nix

Nix is a functional package manager that allows you to manage system configurations and packages deterministically via its own functional programming language. We are in the process of building a Nix‑based CI, and the next step is adding infrastructure to run workloads in the browser in order to test our products.

• Familiarize yourself with Nix
• Design and implement a new testing infrastructure to fit in with our CI
• Add test workflows to our products

Requirements

• Being enrolled in a BSc/MSc or alternative education program in Computer Science or equivalent, ideally in the last year. Working experience in alternative will also be considered.
• Some practical C/C++ development experience (including University projects) is required
• Understanding of object‑oriented design principles
• Residence and right to work in the Netherlands

About Leaning Technologies

Leaning Technologies ( makes WebAssembly tools to run any software on any browser.

We make solutions that enable C/C++, Java, Flash, and native Linux applications to be compiled, emulated and virtualised into HTML5/WebAssembly. Our tools are used to develop high‑performance web apps in ‘traditional’ programming languages, to port existing code to the Web, or to preserve legacy applications by converting/emulating them to HTML5. We have a global client base including multiple Fortune‑100 companies and public sector organisations, in sectors including financial services, CAD software, HR and operations, logistics, defence and aerospace, retail, science and education, and videogames.

Our incredibly talented, tight‑knit team works from different locations with a hybrid remote/office approach. Our main offices are Leeds, United Kingdom and Amsterdam, The Netherlands. We value a great, informal work environment, high flexibility, and having genuine fun and excitement every day at work.

Want to see what it is all about? Join our Discord: and have a chat with our developers!

#J-18808-Ljbffr