Encode & decode strings, bytes, and integers to Base62

Base62 is ideal for URL shortening, creating readable codes, and compact data representation, because it compresses large values into shorter, alphanumeric strings, maximizing space efficiency and readability.

npm install @sindresorhus/base62

import base62 from '@sindresorhus/base62';

const encodedString = base62.encodeString('Hello world!');
console.log(encodedString);
//=> '28B5ymDkgSU62aA0v'

console.log(base62.decodeString(encodedString));
//=> 'Hello world!'

console.log(base62.encodeString('🦄'));
//=> '95s3vg'

console.log(base62.encodeInteger(1337));
//=> 'LZ'

It uses the most common alphabet for Base62: 0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz

Encodes a string to a Base62 string.

Decodes a Base62 encoded string created with encodeString() back to the original string.

Encodes bytes to a Base62 string.

Decodes a Base62 string created with encodeBytes() back to bytes.

Encodes a non-negative integer to a Base62 string.

Decodes a Base62 string to an integer.

Encodes a non-negative bigint to a Base62 string.

Decodes a Base62 string to a bigint.

You can use a custom alphabet by using the Base62 class:

import {Base62} from '@sindresorhus/base62';

// Create instance with custom alphabet
const customBase62 = new Base62({
	alphabet: 'ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789'
});

console.log(customBase62.encodeInteger(1337));
//=> 'Vj' (different from default 'LZ')

// Or use special characters
const symbolBase62 = new Base62({
	alphabet: '!@#$%^&*()_+-=[]{}|;:,.<>?/~`0123456789ABCDEFGHIJKLMNOPQRSTUVW'
});
console.log(symbolBase62.encodeInteger(42));
//=> 'D'

Create a new Base62 encoder/decoder instance.

Type: object

Type: string
Default: '0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz'

Custom alphabet containing exactly 62 unique characters.

The Base62 class has the same methods as the exported functions: encodeString(), decodeString(), encodeBytes(), decodeBytes(), encodeInteger(), decodeInteger(), encodeBigInt(), and decodeBigInt().