randarium
Identifiers

ULID Generator

Generate deterministic, uppercase ULID-style identifiers without a clock, making them useful for repeatable fixtures and examples.

Also known as: lexicographically sortable id

seeded · synthetic data

Presets

Output

No output yet — set your options and hit .
About this tool, tips & examples

What it does

The ULID Generator produces 26-character, uppercase ULID-style identifiers — the lexicographically sortable alternative to UUIDs — up to 1,000 per run. This implementation is deliberately clock-free: values are derived entirely from the seed, so fixtures are pure and reproducible rather than tied to generation time.

Common use cases

  • Test fixtures — ULID-shaped ID columns that regenerate identically on every machine and test run.
  • Log and database examples — realistic identifiers for documentation and demo tables (presets from 1 to 100 IDs).
  • Parser and storage tests — 26-character Crockford-base32 values for validating ULID handling code.
  • UI development — ID displays, truncation, and copy buttons exercised with the real format.

Settings

  • How many — 1 to 1,000 ULIDs, exportable as text, CSV, or JSON.
  • Seed — the same seed regenerates the identical list.

Privacy note

IDs are generated locally in your browser; nothing is uploaded. These are seeded fixtures: not real-time-ordered, not unique beyond the batch, and never suitable as security tokens — production ULIDs should come from a real ULID library, secrets from the Secure Token Generator.

FAQ

What makes real ULIDs sortable? The first 10 characters encode a millisecond timestamp, so IDs sort by creation time — the property that makes them database-friendly. This generator is clock-free by design, so these values trade that for reproducibility.

ULID vs UUID vs Nano ID? UUID is the ubiquitous standard; ULID adds time-sortability in a compact 26 characters; Nano ID optimizes for short URL-safe strings. All three have generators here — match whatever your system uses.

Why uppercase? The ULID spec uses Crockford base32, canonically uppercase, avoiding ambiguous characters — part of why ULIDs are pleasant to read aloud.