Security & CryptoLesson 344Free preview

ULID Generator

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Summary

ULID (Universally Unique Lexicographically Sortable Identifier) is a 128-bit identifier written as 26 Crockford Base32 characters. The initial section contains a millisecond timestamp, followed by randomness, so that the ID can be sorted based on the time of manufacture. This property makes ULIDs more database-friendly than the completely random UUIDv4.

Key points

The ULID consists of 48 bits of timestamp and 80 bits of randomness
The length of the ULID text is 26 characters Crockford Base32
ULIDs can be lexicographically sorted by time
The capital and minor letters are considered the same when decoding
UUIDv4 is completely random so it doesn't have a built-in timeline.

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