Shard Detail

base62 v0.1.2

Base62 encoder/decoder for Crystal
crystal base62 url-shortener conversion encoding

Install & Use

Add the following code to your project's shard.yml under:

dependencies to use in production
- OR -
development_dependencies to use in development

  github: Sija/

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Crystal shard for Base62 encoding/decoding. It's especially useful for converting data into shortened strings suitable for URL shortening and/or obfuscating auto-incrementing resource ids from being exposed through RESTful APIs.

What is Base62 encoding?

Base62 encoding converts numbers to ASCII strings (0-9, a-z and A-Z) and vice versa, which typically results in comparatively short strings. Such identifiers also tend to be more readily identifiable by humans.


Add this to your application's shard.yml:

    github: Sija/


require "base62"

Base62.encode(999)  # => "G7"
Base62.decode("G7") # => 999

This uses the default ASCII character set for encoding/decoding.

It's also possible to define a custom character set instead:

charset = "~9876543210ABCDEFGHIJKLMNOPQRSTU$#@%!abcdefghijklmnopqrstuvw-="

Base62.encode(999, charset)  # => "F3"
Base62.decode("F3", charset) # => 999

Note that charset typically expects the respective string to contain exactly 62 unique character. In fact, it's also possible to use characters sets with more than 62 characters in order to achieve shorter identifiers for large numbers.


  1. Fork it (
  2. Create your feature branch (git checkout -b my-new-feature)
  3. Commit your changes (git commit -am 'Add some feature')
  4. Push to the branch (git push origin my-new-feature)
  5. Create a new Pull Request


  • @Sija Sijawusz Pur Rahnama - creator, maintainer