base62.js

Like base64, but base62. Converts back and forth between base62 strings and (byte) arrays.

Demo

Base62 Data Encoding & Decoding:

https://base62.js.org/

GitHub-style Base62 Token Generator & Verifier:

https://therootcompany.github.io/base62-token.js/

Base62 Dictionaries

There are 3 widely-used, generic Base62 dictionaries, all of which are based on the alphanumeric character set (i.e. 0-9, A-Z, a-z).

Legographic (digits, upper, lower)

0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz

BaseX (digits, lower, upper)

0123456789abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ

Truncated Base64 (upper, lower, digits)

ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789

For general encoding and decoding you should use one of these.

However, for secure tokens for which you don't want an attacker to have the advantage of being able to verify a token offline (i.e. you want them to hit your API rate limiting), you should use a randomized dictionary.

Randomized (a.k.a. Secure)

Each call to Base62.secureDictionary() will produce a different alphanumeric Base62

Lexographic Sort (a.k.a. GMP Base62)

console.log(Base62Token.Base62);
// "0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz"

BaseX (a.k.a. WikiPedia Base62)

console.log(Base62Token.BaseX62);
// "0123456789abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ"

Truncated Base64

console.log(Base62Token.Base6462);
// "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789"