Nullcode — Send messages no one else can read
encode · send · disappear
Start encodingfree to use · no account needed
How it works
01
Write
Type your message. Pick a cipher. Choose a secret key only you and your recipient know.
Type your message. Pick a cipher. Choose a secret key only you and your recipient know.
02
Encode
Your message becomes unreadable gibberish — numbers, symbols, scrambled letters. Send it anywhere.
Your message becomes unreadable gibberish — numbers, symbols, scrambled letters. Send it anywhere.
03
Decode
The recipient opens Nullcode, pastes the message, enters the same key. Only then does it make sense.
The recipient opens Nullcode, pastes the message, enters the same key. Only then does it make sense.
Choose your cipher
Free
Vigenère
Uses a repeating keyword to shift each letter differently. The same letter encodes differently every time it appears — far harder to crack than a simple substitution. A classic cipher used by diplomats and spies for centuries.
Free forever
Pro
Polybius
Converts every letter into a pair of coordinates on a secret 5×5 grid built from your key. Output looks like streams of numbers — completely unreadable without knowing both the cipher and the key.
Included in PRO unlock
Pro
Substitution
Builds an entirely scrambled alphabet from your keyword — every key produces a different mapping. No two keys ever encode the same way. The most customisable cipher and the hardest to crack without the exact key.
Included in PRO unlock
Unlock Polybius + Substitution — once, forever. €2.99
One payment. No subscription. Works on any device with your unlock code.