Releases, technical deep dives and news about CheerpX from the Leaning Technologies engineering blog.https://labs.leaningtech.comhttps://labs.leaningtech.com/blog/internshipshttps://labs.leaningtech.com/blog/internshipsOur interns describe their 6 month internships at Leaning Technologies Thu, 06 Nov 2025 00:00:00 GMTCheerpJCheerpXBrowserPodLeaning Technologieshttps://labs.leaningtech.com/blog/webvm-claudehttps://labs.leaningtech.com/blog/webvm-claudeYou can now use AI to control WebVM, both in terminal and graphical mode Mon, 17 Mar 2025 00:00:00 GMTCheerpXProjects & DemosTechnicalhttps://labs.leaningtech.com/blog/cx-10https://labs.leaningtech.com/blog/cx-10CheerpX is a WebAssembly-based virtualization engine for x86 binaries. It is built on top of standard Web technologies, and runs fully in the browser, with no need for server side execution of any sort. This article will explain the architecture of CheerpX and show detailed examples for possible use cases of this technology. Wed, 04 Dec 2024 00:00:00 GMTCheerpXReleasehttps://labs.leaningtech.com/blog/webvm-20https://labs.leaningtech.com/blog/webvm-20WebVM is a full Linux environment running in the browser, client-side. It is a complete virtual machine, with support for persistent data storage, networking and, as of today’s release, Xorg and complete desktop environments. This article will explain the WebVM architecture, how the main components work, and what you can build with this technology. Wed, 13 Nov 2024 00:00:00 GMTCheerpXProjects & Demoshttps://labs.leaningtech.com/blog/join-the-webvm-hackathonhttps://labs.leaningtech.com/blog/join-the-webvm-hackathonWebVM: The Hackathon is a global hybrid event open to all developers. Dive into terminal-based solutions using CheerpX and showcase your coding skills for a chance to win amazing prizes. Wed, 02 Oct 2024 00:00:00 GMTCheerpXCheerpCommunityhttps://labs.leaningtech.com/blog/branch-hintinghttps://labs.leaningtech.com/blog/branch-hintingAround a month ago, the WebAssembly Community Group voted to advance the [Branch Hinting proposal](https://github.com/WebAssembly/branch-hinting) to phase 4, effectively recommending its addition to the standard, and the Working Group formally added it to the standard by voting it into phase 5 last week. This was a big achievement for me, as the proposal Champion from its inception almost 4 years ago, and for [Leaning Technologies](https://leaningtech.com) (my company), who sponsored this work. In this article I will explain the purpose of the proposal, and the journey that brought it from idea to standard. Tue, 16 Jul 2024 00:00:00 GMTCheerpXTechnicalhttps://labs.leaningtech.com/blog/beyond-devtools-profiling-webapps-at-the-assembly-levelhttps://labs.leaningtech.com/blog/beyond-devtools-profiling-webapps-at-the-assembly-levelThanks to groundbreaking technologies like CheerpX and CheerpJ, we have successfully redefined what was previously considered achievable within the browser’s environment. While working on such advanced projects, we soon encountered the limitations of a traditional profiling approach, like Chrome’s built-in devtools. As a result, we relied on a custom profiling workflow based on internal Chrome tracing for years which was due for an improvement. Wed, 28 Jun 2023 00:00:00 GMTCheerpXTechnicalhttps://labs.leaningtech.com/blog/mini-webvm-your-linux-box-from-dockerfile-via-wasmhttps://labs.leaningtech.com/blog/mini-webvm-your-linux-box-from-dockerfile-via-wasmWebVM is a Linux-like virtual machine running fully client-side in the browser. It is based on CheerpX: a x86 execution engine in WebAssembly by Leaning Technologies. With today’s update, you can deploy your own version of WebVM by simply forking the repository on GitHub and editing the included Dockerfile. A GitHub Actions workflow will automatically deploy it to GitHub pages. Mon, 22 May 2023 00:00:00 GMTCheerpXProjects & Demoshttps://labs.leaningtech.com/blog/webvm-virtual-machine-with-networking-via-tailscalehttps://labs.leaningtech.com/blog/webvm-virtual-machine-with-networking-via-tailscaleWebVM, our virtual Linux environment running fully client-side in the browser, now supports networking via Tailscale.Wed, 05 Oct 2022 00:00:00 GMTCheerpXProjects & DemosTechnicalhttps://labs.leaningtech.com/blog/pythonfiddle-fully-private-client-side-sample-code-execution-and-sharinghttps://labs.leaningtech.com/blog/pythonfiddle-fully-private-client-side-sample-code-execution-and-sharingA recurrent need for anybody practising programming is running (and sharing) small snippets of code to quickly test an idea or ask for feedback. These kinds of Web applications are generally called ‘fiddles’, and there are plenty of them out there. The common use cases for fiddles are in education, but anyone can find themselves needing to use one to avoid having to set up a full native execution environment. Wed, 14 Sep 2022 00:00:00 GMTCheerpXProjects & Demoshttps://labs.leaningtech.com/blog/fantastic-tail-calls-and-how-to-implement-themhttps://labs.leaningtech.com/blog/fantastic-tail-calls-and-how-to-implement-themThis article aims at demystifying WebAssembly tail calls while giving the reader an idea of how we have implemented the feature in WebKit. Mon, 11 Jul 2022 00:00:00 GMTCheerpXTechnicalhttps://labs.leaningtech.com/blog/webvm-server-less-x86-virtual-machines-in-the-browserhttps://labs.leaningtech.com/blog/webvm-server-less-x86-virtual-machines-in-the-browserWe made a server-less virtual Linux environment that runs unmodified Debian binaries in the browser. This is powered by CheerpX, a WebAssembly virtualization platform. Feel free to play with it and report bugs: https://webvm.io Tue, 01 Feb 2022 00:00:00 GMTCheerpXProjects & Demoshttps://labs.leaningtech.com/blog/announcing-cheerpx-for-flash-a-solution-to-extend-the-life-of-flash-applications-post-2020https://labs.leaningtech.com/blog/announcing-cheerpx-for-flash-a-solution-to-extend-the-life-of-flash-applications-post-2020Today we are proud to announce CheerpX for Flash, a solution to run existing Flash applications on any browser after December 2020. Mon, 21 Sep 2020 00:00:00 GMTCheerpXReleasehttps://labs.leaningtech.com/blog/extreme-webassembly-2-the-sad-state-of-webassembly-tail-callshttps://labs.leaningtech.com/blog/extreme-webassembly-2-the-sad-state-of-webassembly-tail-callsHere at Leaning Technologies, we use WebAssembly daily to create unique and seemingly impossible technologies, like CheerpX (a WebAssembly virtual machine designed to safely run arbitrary x86 libraries and applications in browser) and CheerpJ (a solution to compile and run Java applications in the browser). Tue, 18 Aug 2020 00:00:00 GMTCheerpXTechnicalhttps://labs.leaningtech.com/blog/extreme-webassembly-1-pushing-browsers-to-their-absolute-limitshttps://labs.leaningtech.com/blog/extreme-webassembly-1-pushing-browsers-to-their-absolute-limitsThis is the first of a series of posts about the problems we have found on our way when using WebAssembly, and how we have solved them. Tue, 16 Jun 2020 00:00:00 GMTCheerpXTechnical