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, optional monotonic batch ordering, up to 50 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, optional monotonic ordering within one batch, a count from 1 to 50, then Generate. Entropy uses crypto.getRandomValues — never Math.random. Each row shows the embedded creation timestamp.

Options

Uppercase
ULID spec convention is uppercase. Switch to lowercase for case-sensitive stores.
Count (1–50)
Generate multiple ULIDs for fixtures without flooding the UI — capped at 50.
Monotonic (within one Generate click)
When enabled and count > 1, IDs from a single Generate click are strictly lexicographically ascending (same millisecond, incremented randomness). Does not carry state across separate clicks or page reloads.

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 paste-to-decode?

This is a generator — decoding is shown for IDs you just generated. Pasting arbitrary ULIDs is out of scope for v1.

Are ULIDs monotonic?

Only when you enable Monotonic and generate more than one ID in a single click — then the batch is strictly ascending. Each separate Generate click uses a fresh timestamp snapshot.

Developer utilities

Timestamps, UUID, ULID, Nanoid, cron, passwords, regex, slugify, number bases, case, text diff, and chmod — all client-side.

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