Try Lua, the small scripting language used in Roblox, game mods, Neovim and many apps, right in your browser. Code runs on Fengari, a complete Lua 5.3 virtual machine written in JavaScript, with print, io.write and io.read for input, and a 10-second limit so an endless loop cannot freeze the page.
loading toolHow to run Lua 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
- io.read("n") reads a number from the Input box; io.read() reads a whole line.
- Use local for variables inside functions: it is faster and avoids surprises.
Questions
Which Lua version is it?
Lua 5.3, with the standard string, table, math, utf8, os and coroutine libraries. Integer division (//) and bitwise operators work.
Is this Roblox Luau?
No. Luau adds types and some extra syntax; plain Lua code works in both, but Roblox-only functions such as game:GetService are not available here.
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.
