How do I read Brainfuck code?

You generally don't — you run it. The language is deliberately unreadable; executing it and observing the output is the intended approach.

Is running Brainfuck here safe?

Yes. It executes in a sandboxed interpreter in your browser with no filesystem or network access, and execution is bounded so an infinite loop can't hang the page.

A JavaScript obfuscation technique that writes any program using only six characters, exploiting the language's type coercion. It is used in puzzles and, less happily, in obfuscated malicious scripts.

Brainfuck Decoder

Execute Brainfuck code and unpack JSFuck esoteric payloads.

live · client-sideClassical & Obfuscated Ciphersfree · no sign-up

RAW INPUT

DECODED

Output appears here as you type — decoded on your device.

Input is processed on your device. Nothing you paste is sent anywhere.

What is the Brainfuck Decoder?

Brainfuck is an esoteric programming language with only eight instructions operating on a memory tape, and an interpreter runs that code to produce its output — usually the hidden message a puzzle encoded as Brainfuck.

Brainfuck's entire instruction set is > < + - . , [ and ]. They move a data pointer along a byte tape, increment or decrement the current cell, output or input a character, and loop while the current cell is non-zero. Everything else in a Brainfuck file is a comment, which is why these programs look like punctuation soup.

It is Turing-complete despite the minimalism, which makes it a favourite for code golf and for CTF challenges where a message is hidden as a program that prints it. Running the code is the only reliable way to read it — static analysis of Brainfuck is a losing game.

JSFuck is the same idea in JavaScript: any program can be written using only []()!+ by exploiting type coercion. The output looks like thousands of brackets, and evaluating it is what reveals the payload — which is also why it shows up in obfuscated malicious scripts.