Brainf*** Interpreter

Runs locally. Share links use the URL fragment (not sent to the server). Debugger is capped to avoid lockups.

tools · home

Program

Share uses URL #p=.... Debug buttons operate on an in-memory VM snapshot.
Input (bytes; interpreted as UTF-8 text)
Output

Settings

Tape size
Step limit
Cell mode
Debug window
Break: ip ==
Break: ptr ==
Break: cell ==
Break: out bytes ≥
Run-until cap
Break: opcode ==
Trace cap (steps)
Watch cells (comma idx)
Trace output (kept in-memory; export JSON/CSV)

Trace diff (first divergence)

Paste two exported trace JSON blobs → find the first step where state diverges.

Notes:

Debugger (capped)

Shows a window around the pointer (wraps). “Reset (debug)” initializes VM state.