Web playground

Run X++ right here

A faithful port of the ZITR VM, running entirely in your browser. Same pseudocode, same semantics — quirks faithfully included. Press Ctrl+Enter to run.

editor

input (stdin) for in reads — one line each

output

output appears here — press Run (or Ctrl/Cmd + Enter)

idle

What runs here?

The same strict-pseudocode language as the native VM — ported to JavaScript down to the details: out spacing, nil arithmetic, dict display style, even the sum() accumulator quirk.

Sandbox limits

Runs time out after 8 s, recursion caps around ~1,500 frames, and read / write use an in-memory disk. The native VM handles 20,000+ frames and your real filesystem.

Take it further

Learn the whole language on the Learn page, browse copy-paste examples, or grab the real engine from GitHub — one command installs everything.