ULID Generator Online — Crockford Time-Sortable IDs

Generate ULIDs (48-bit time + 80-bit randomness, Crockford Base32, 26 chars) with Web Crypto. Uppercase by default, up to 20 IDs — nothing is uploaded.

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ULID generator — developer notes
ULID = 48-bit milliseconds + 80-bit randomness, Crockford Base32 (26 chars). Time-sortable, no ambiguous I/L/O/U characters.

How generation works

Choose uppercase (spec convention) or lowercase, a count from 1 to 20, then Generate. Entropy uses crypto.getRandomValues — never Math.random.

Options

Uppercase
ULID spec convention is uppercase. Switch to lowercase for case-sensitive stores.
Count (1–20)
Generate multiple ULIDs for fixtures without flooding the UI — capped at 20.

Examples

Default uppercase

Settings

uppercase=on, count=1

Output

01ARYZ6S41… (26 chars)

Lowercase batch

Settings

uppercase=off, count=3

Output

three newline-separated ULIDs

Related utilities

For classic UUIDs use the UUID generator, or compact IDs via the Nanoid generator.

ULID generator FAQ

Time-sortable IDs

ULID vs UUID?

ULIDs are time-sortable and easier to read (26 Crockford chars). UUID v4 is pure random; UUID v7 is also time-ordered but hex-encoded.

Is generation private?

Yes — everything runs in your browser via Web Crypto.

Why no ULID decoder?

Out of scope for v1: generate only. An inspect tool may come later.

Are ULIDs monotonic?

No — each click draws fresh entropy. No monotonic factory in this version.

Looking for converters, encoders, formatters, and minifiers in one place? Developer tools hub Open the curated developer tools catalogue.