Rhun: a small open-source code editor written in assembly

On October 1, developer Vladyslav Shvedov posted Rhun, a small, fast code editor written in assembly, to Hacker News as a Show HN entry. The thread drew more than 40 points and 23 comments. The project is open source under the MIT license, its code lives on GitHub, and the latest release is version 0.16.2.

What Rhun offers

The editor ships with tabs, syntax highlighting, find and replace, fuzzy search and an optional Vim mode. A built-in terminal runs builds, shell commands and coding agents beside the code, and a Git panel covers diffs, staging, commits, pull and push. Commit messages can optionally be drafted with a Claude or Codex subscription or a local Ollama model, and an agents panel follows running Claude Code and Codex sessions. The site lists 39 light and dark themes, and the AI features are optional throughout.

Why assembly

In the Hacker News thread, Shvedov said the plan is to add as few new features as possible and keep performance, launch time, memory use and disk footprint where they are. He described Rhun as an "anti-VS Code": feature-poor and short on configuration, but small and fast, and called it "nano+ with a GUI". One commenter measured its memory use on Windows at 7.9 MB, against 12.2 MB for gvim, 35.5 MB for Emacs and 291.1 MB for VSCodium. Several commenters praised the editor's speed; others were skeptical, saying the website and the source code showed signs of AI-generated work.

Platforms and status

Rhun runs on Linux (x86-64), macOS (Apple silicon) and Windows. Linux and macOS install with a one-line shell script. On Windows 10 (1809 or later) and Windows 11 the editor arrives as a ZIP from the releases page, with an optional PowerShell installer that adds a Start menu shortcut and the rhun command. New versions are offered in the status bar, though Windows users currently need to rerun the installer; the author says better auto-updating is coming in the next major release, and that Rhun is free and collects no telemetry. The GitHub repository was created on September 26 and had about 30 stars by October 2. The editor bundles the Instrument Sans and Iosevka fonts under the SIL Open Font License.