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A javascript Base62 encode/decoder for node.js

What is Base62 encoding?

From wikipedia:

Base62 is a priority system to the base 62, which for encoding large numbers using ASCII is character. The digits 0-9 (value 0-9), uppercase letters A-Z (value 10-35) and lowercase letters a-z (value 36-61) are used.

Due to the high number of base formed shorter strings than with the decimal or hexadecimal system , which mainly offers two advantages:

  • They can be entered by a human being faster and with a smaller risk of error. In this case, a font should be selected in which characters that can be confused, such as small L and large i, or zero, and large O, are distinguishable.
  • Length restrictions, eg when a number is to be used as part of an identifier or file name, can be bypassed. However, it should be noted that the processing system is case-sensitive.


npm install base62

or for yarn:

yarn add base62


Default Character Set Example

Base62 = require('base62')
Base62.encode(999)  // 'g7'
Base62.decode('g7') // 999

Custom Character Set Example

The default character set is 0-9a-zA-Z. This can be updated to a custom character set. Naturally, it must be 62 characters long.

Instead of the character set 0-9a-zA-Z you want to use 0-9A-Za-z, call the setCharacterSet() method on the Base62 object passing in the string "0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz". Note that all characters must be unique.

Base62 = require('base62')
Base62.encode(999)  // 'G7'
Base62.decode('G7') // 999


Source hosted at GitHub. Report Issues/Feature requests on GitHub Issues.

Note on Patches/Pull Requests

  • Fork the project.
  • Make your feature addition or bug fix.
  • Add tests for it. This is important so I don't break it in a future version unintentionally.
  • Send me a pull request. Bonus points for topic branches.


Copyright (c) 2016 Andrew Nesbitt. See LICENSE for details.