ulid-rs

July 16, 2026 ยท View on GitHub

Build Status Crates.io docs.rs

This is a Rust implementation of the ulid project which provides Universally Unique Lexicographically Sortable Identifiers.

Quickstart

use ulid::Ulid;

// Generate a ulid
let ulid = Ulid::generate();

// Generate a string for a ulid
let s = ulid.to_string();

// Create from a String
let res = Ulid::from_string(&s);

assert_eq!(ulid, res.unwrap());

Crate Features

  • std (default): Flag to toggle use of std and rand. Disable this flag for #[no_std] support.
  • serde: Enables serialization and deserialization of Ulid types via serde. ULIDs are serialized using their canonical 26-character representation as defined in the ULID standard. An optional ulid_as_u128 module is provided, which enables serialization through an Ulid's inner u128 primitive type. See the documentation and serde docs for more information.
  • uuid: Implements infallible conversions between ULIDs and UUIDs from the uuid crate via the std::convert::From trait.

Benchmark

Benchmarks were run on my desktop (Win 10/WSL2 Ubuntu; Ryzen 7 5950x). Run them yourself with cargo bench.

test bench_from_string        ... bench:          13 ns/iter (+/- 0)
test bench_from_time          ... bench:          13 ns/iter (+/- 0)
test bench_generator_generate ... bench:          29 ns/iter (+/- 0)
test bench_new                ... bench:          31 ns/iter (+/- 1)
test bench_to_str             ... bench:           7 ns/iter (+/- 0)
test bench_to_string          ... bench:          19 ns/iter (+/- 0)

Changelog

v3.0.0

  • Rename Ulid::gen() (previously Ulid::new()) to Ulid::generate() for better compatability with edition 2024

v2.0.1

  • Add support for rand = "0.10"
  • Replaced MonotonicError::Overflow with Overflow. Generator results can now be properly overflowed using Overflow::commit_overflow_random() or Overflow::commit_overflow_random().
    • To keep existing client behavior, drop the Overflow value. generator.generate().map_err(|_| MyOverflowError)
  • Rename Ulid::new() to Ulid::new() for better compatability with edition 2024
  • Add Ulid::max() and Ulid::is_max()
  • Add const to Ulid::array_to_str() (Thanks Hermholtz)
  • Removed deprecated Ulid::to_str()