Base91 Encoder / Decoder
Encode text using the basE91 algorithm or decode a Base91 string back to text. Base91 produces a more compact result than Base64 by using 91 printable characters instead of 64, while remaining 100% computed in your browser.
How It Works
Unlike Base64, which splits data into fixed 6-bit groups, basE91 packs bytes into 13- or 14-bit blocks and converts them into pairs of symbols from an alphabet of 91 printable ASCII characters, improving compression by about 3% compared to Base64.
Is Base91 compatible with all URLs?
No: the Base91 alphabet includes characters like ", <,
>, or & that need to be escaped in a URL or HTML.
It's mainly suitable for storage in text files or transmission in protocols that accept
printable ASCII characters without restriction.
Why is my result shorter than Base64?
Because each pair of Base91 symbols encodes more bits than a Base64 character (about 6.5 bits per symbol vs. 6 bits for Base64), the final result is generally slightly shorter for the same original data.
No data leaves your device: encoding and decoding are computed locally in JavaScript.