A fast little-endian implementation of Douglas Crockford's Base32 specification.

Gem Version

What's in the box?

✅ Simple usage documentation written to get started fast. Check it out!

⚡ A pretty fast implementation of Crockford32 in pure ruby. Check it out!

📚 YARD generated API documentation for the library. Check it out!

🤖 RBS types for your type checking wants. Check it out!

💎 Tests against many Ruby versions. Check it out!

🔒 MFA protection on all gem owners. Check it out!


Add this line to your application's Gemfile:

gem 'crockford32'

And then execute:

$ bundle install

Or install it yourself as:

$ gem install crockford32

Ruby Versions

This gem is tested against the following Ruby versions:

  • 2.6.0
  • 2.6.9
  • 2.7.0
  • 2.7.5
  • 3.0.0
  • 3.0.3
  • 3.1.0
  • 3.1.1


Encode data with the encode method:

encoded = Crockford32.encode(1234) # encoded = "J61"

See the the encode API documentation for error details.

Decode a value with the decode method:

decoded = Crockford32.decode("J61") # decoded = 1234

See the the decode API documentation for error details.


You can also encode and decode strings by providing the :string value as the into: argument to decode. Encoding a string requires no special consideration.

encoded = Crockford32.encode("abc") # encoded = "1KR66"
decoded = Crockford32.decode(encoded, into: :string) # decoded = "abc"

When decoding you may receive a byte string if the encoded value is not alphanumeric:

decoded = Crockford32.decode("J61", into: :string) # decoded = "\xD2\x04"

Padding to a Length

You can ensure your encoded values are a specific length by specifying a length: on encode:

encoded = Crockford32.encode(1234, length: 5) # encoded = "J6100"

The padding is always "0" values and is always appended to the end of the encoded string. Whatever you specify as the length: will be the length of the encoded string you receive.

Check Symbols

If you wish to append a check symbol for simple modulus-based error detection both encode and decode support it with the check: keyword.

encoded = Crockford32.encode(1234, check: true) # encoded = "J61D". "D" is the checksum symbol.
decoded = Crockford32.decode(encoded, check: true) # decoded = 1234. Checksum is tested.

An error will be raised if the decoding process does not pass the checksum:

decoded = Crockford32.decode("J71D", check: true) # Notice the 6 changed to a 7.
~/.../crockford32/lib/crockford32.rb:43:in `decode': Value J71 has checksum 8 but requires 13 (Crockford32::ChecksumError)
    from (irb):2:in `<main>'
    from bin/console:8:in `<main>'

If you specify a length: and check: true when encoding, the checksum will be included as part of the length:.

Encoding Type Support

This library currently supports encoding Integer and String values.

Little-Endian Encoding

The encoding example above shows the little-endian results of encoding a number. Some libraries encode using big-endian and will return "16J" when the number 1234 is encoded.

This library always uses little-endian.

More Information

For more detailed information about the library see the API documentation.



To get started development on this gem run the bin/setup command. This will install dependencies and run the tests and linting tasks to ensure everything is working.

For an interactive console with the gem loaded run bin/console.


Use the bundle exec rake test command to run unit tests. To install the gem onto your local machine for general integration testing use bundle exec rake install.

To test the gem against each supported version of Ruby use bin/test_versions. This will create a Docker image for each version and run the tests and linting steps.


Do the following to release a new version of this gem:

  • Update the version number in lib/crockford32/version.rb
  • Ensure necessary documentation changes are complete
  • Ensure changes are in the
  • Create the new release using bundle exec rake release

After this is done the following side-effects should be visible:

  • A new git tag for the version number should exist
  • Commits for the new version should be pushed to GitHub
  • The new gem should be available on

Finally, update the documentation hosted on GitHub Pages:

  • Check-out the gh-pages branch
  • Merge main into the gh-pages branch
  • Generate the documentation with bundle exec rake yard
  • Commit the documentation on the gh-pages branch
  • Push the new documentation so GitHub Pages can deploy it


Benchmarking is tricky and the goal of a benchmark should be clear before attempting performance improvements. The goal of this library for performance is as follows:

This library should be capable of encoding and decoding IDs at a rate which does not make it a bottleneck for the majority of web APIs.

Given the above goal statement, these benchmarks run on the following environment:

Attribute Value
Ruby Version 3.1.0
MacOS Version Catalina 10.15.7 (19H1615)
MacOS Model Identifier MacBookPro10,1
MacOS Processor Name Quad-Core Intel Core i7
MacOS Processor Speed 2.7 GHz
MacOS Number of Processors 1
MacOS Total Number of Cores 4
MacOS L2 Cache (per Core) 256 KB
MacOS L3 Cache 6 MB
MacOS Hyper-Threading Technology Enabled
MacOS Memory 16 GB

When run using a constant 16 bytes of data in the above environment the performance is approximately as follows:

~/…/crockford32› date && ruby test/benchmarks/current.rb
Fri Feb 18 15:35:49 PST 2022
Warming up --------------------------------------
              encode    11.498k i/100ms
              decode    10.550k i/100ms
       encode string     7.686k i/100ms
       decode string     6.798k i/100ms
Calculating -------------------------------------
              encode    117.614k (± 3.5%) i/s -    597.896k in   5.090119s
              decode    108.253k (± 3.2%) i/s -    548.600k in   5.073326s
       encode string     78.690k (± 3.1%) i/s -    399.672k in   5.084255s
       decode string     69.707k (± 3.5%) i/s -    353.496k in   5.077700s

Being conservative in estimation 30k i/s round trip decoding and encoding cycles should be possible. This achieves the performance goal.