What implementation of BQN?

CBQN (the C implementation, currently the fastest).

How do I type BQN glyphs?

The playground editor accepts pasted Unicode directly; BQN's official docs list keyboard input methods per OS.

How is the code sandboxed?

A fresh Firecracker microVM per submission, same isolation model AWS Lambda uses.

BQN · online compiler

Run BQN online

Run BQN online — the array-programming language, browser-hosted.

Version

BQN

Firecracker microVM live per-test verdicts multi-file compile

BQN is a modern array language descended from APL and J, designed by Marshall Lochbaum with an emphasis on composability, immutability, and a clean type system. If you ever wanted to try APL-lineage code without hunting down a symbol keyboard, this is the fastest path in.

ls-judge runs the CBQN implementation in a Firecracker microVM per submission. Feed stdin, see stdout — nothing to install locally.

Starter code

What you get in BQN

Clicking "Run now" opens the playground with this exact code and a matching test case pre-loaded — passes on first Run.

bqn

BQN 0

n ← •BQN •GetLine ""
•Out •Fmt (2×n)

stdin →

expected →

FAQ

Common questions about BQN on ls-judge

What implementation of BQN?: CBQN (the C implementation, currently the fastest).
How do I type BQN glyphs?: The playground editor accepts pasted Unicode directly; BQN's official docs list keyboard input methods per OS.
Is this free?: Yes.
How is the code sandboxed?: A fresh Firecracker microVM per submission, same isolation model AWS Lambda uses.