Sqids Crystal

Sqids (pronounced "squids") is a small library that lets you generate YouTube-looking IDs from numbers. It's good for link shortening, fast & URL-safe ID generation and decoding back into numbers for quicker database lookups.

Getting started

Add the dependency to your shard.yml:

dependencies:
  sqids:
    github: sqids/sqids-crystal

And then execute:

shards install

Examples

Simple encode & decode:

sqids = Sqids.new
id = sqids.encode([1, 2, 3]) # "86Rf07"
numbers = sqids.decode(id) # [1, 2, 3]

Note 🚧 Because of the algorithm's design, multiple IDs can decode back into the same sequence of numbers. If it's important to your design that IDs are canonical, you have to manually re-encode decoded numbers and check that the generated ID matches.

Enforce a minimum length for IDs:

sqids = Sqids.new(min_length: 10)
id = sqids.encode([1, 2, 3]) # "86Rf07xd4z"
numbers = sqids.decode(id) # [1, 2, 3]

Randomize IDs by providing a custom alphabet:

sqids = Sqids.new(alphabet: "FxnXM1kBN6cuhsAvjW3Co7l2RePyY8DwaU04Tzt9fHQrqSVKdpimLGIJOgb5ZE")
id = sqids.encode([1, 2, 3]) # "B4aajs"
numbers = sqids.decode(id) # [1, 2, 3]

Prevent specific words from appearing anywhere in the auto-generated IDs:

sqids = Sqids.new(blocklist: Set.new(%w[86Rf07]))
id = sqids.encode([1, 2, 3]) # "se8ojk"
numbers = sqids.decode(id) # [1, 2, 3]

License

MIT