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Runno

Runno is a collection of JavaScript Packages for running code in various languages inside a sandbox. It's made of the following packages:

• @runno/runtime - web components and headless tools for running code examples in the browser.
• @runno/sandbox - a secure sandbox for running code examples in Node and other JS Runtimes.
• @runno/wasi - an isomorphic package for running WebAssembly WASI binaries inside a sandbox.
• @runno/mcp - an MCP Server for running code using the @runno/sandbox package.

There's also a deprecated Python package called runno that works like the sandbox package.

This project is powered by WASI the Web Assembly System Interface. It provides a standard way for programs to interact with an operating system. By emulating this interface, we can provide a fake file system and operating system, all running within JavaScript.

Using @runno/runtime

The @runno/runtime package provides Web Components for running code in the browser.

This is very handy for programming education it means:

• No need for newbies to install complex programming tools to run code
• Programming examples can be made runnable in the browser with no server
• Simple programs can be tested for correctness inside a sandbox on the user's machine

Quickstart

Start by adding @runno/runtime to your package:

npm install @runno/runtime

Import @runno/runtime in whatever place you'll be using the runno elements. The simplest is in your entrypoint file (e.g. main.ts or index.ts).

import "@runno/runtime";

Once you've imported them you can use runno elements on the page.

<runno-run runtime="python" editor controls> print('Hello, World!') </runno-run>

For the code to run though, you'll need to set some HTTP headers:

Cross-Origin-Opener-Policy: same-origin
Cross-Origin-Embedder-Policy: require-corp

These create a cross-origin isolated context which allows the use of SharedArrayBuffer used to implement STDIN.

Supported Runtimes

The system supports a number of runtimes based on existing packages published to WAPM. These runtimes are tied to Runno and will be supported by Runno going forward.

• python - Runs python3 code, not pinned to a particular version but is at least 3.6
• ruby - Runs standard Ruby, not pinned but is at least 3.2.0
• quickjs - Runs JavaScript code using the QuickJS engine
• sqlite - Runs SQLite commands
• clang - Compiles and runs C code
• clangpp - Compiles and runs C++ code
• php-cgi - Runs PHP CGI compiled by VMWare

Running WASI binaries

The runtime also provides a component for running WASI binaries directly.

<runno-wasi src="/ffmpeg.wasm" autorun></runno-wasi>

Examples

There are more examples for how to use Runno in the examples directory in this repo. It includes practical ways you can use Runno, and how to configure it to run.

Full documentation

Visit @runno/runtime to read the full documentation.

How does it work?

Runno uses Web Assembly to run code from JavaScript. Code runs in a unix-like sandbox that connects to a web-based terminal emulator. This means it behaves a lot like running code natively on a linux terminal. It's not perfect, but it's handy for making code examples run.

Plus it's pretty cool that you can just run code in your browser!

Using @runno/sandbox

Quickstart

Shortened. The full README is on GitHub.