ulidx

ULID generation and conversion. A ULID is a 128-bit identifier that is both lexicographically sortable by creation time and random enough to be used as a primary key — 26 characters in Crockford base32, no hyphens.

Install

pip install ulidx

Usage

from ulidx import Ulid

# plain generation
Ulid.generate()                       # '01J8Z9K2M3N4P5Q6R7S8T9V0WX'

# guaranteed strictly increasing within a process, even in the same millisecond
Ulid.generate(n_monotonic=True)

# pin the timestamp (aware or naive datetime, or epoch seconds)
Ulid.generate(n_timestamp=1700000000)

# bulk
Ulid.generate_batch(1000)

# back and forth
value = Ulid.generate()
Ulid.to_timestamp(value)              # float, epoch seconds
Ulid.to_time(value)                   # datetime in UTC+8
Ulid.to_bytes(value)                  # 16 raw bytes
Ulid.by_bytes(Ulid.to_bytes(value))   # round trip
Ulid.to_uuid(value)                   # uuid.UUID
Ulid.from_uuid(some_uuid)             # 26-char str

API

Monotonicity

n_monotonic=True keeps the generator state per thread, so concurrent threads never share a counter. Within a thread, ULIDs produced in the same millisecond strictly increase, which keeps sorting stable when several IDs are created in one tick.

License

MIT