Run Ruby code without installing anything. The official Ruby 3.3 interpreter, compiled to WebAssembly by the ruby.wasm project, runs in a background worker in your browser with its standard library, so puts, gets, blocks, classes and gems from the standard library such as json and set all work.
loading toolHow to run Ruby online
- Type or paste your code.
- If the program asks for input, type one answer per line in the Input box.
- Press Run (or Ctrl + Enter) and read the output below.
Good to know
- gets reads the next line of the Input box; use gets.chomp to drop the line break.
- Methods and variables you define stay available until you reload the page or press Stop.
Questions
Why does the first run take a while?
The Ruby interpreter with its standard library is a large download the first time. Your browser caches it, so later runs start quickly.
Can I install gems?
No. Only the standard library that ships with Ruby is available.
Does my code get uploaded?
No. The checker or runtime is downloaded once from a public CDN (jsDelivr or cdnjs) and then runs inside your browser. Your code never leaves your device.
Is my data private?
Yes. Everything happens inside your own browser: nothing you type or choose is uploaded to us or anyone else.
Is it free?
Completely free, with no sign-up, no watermark and no limit on how many times you use it. Light ads keep the site running.
