UUID & ULID Generator

Generate UUID v4, v7 and v1 plus ULID online. Batch generate, remove hyphens, uppercase output, using cryptographically secure randomness. Runs in your browser.

Runs locally · data never uploaded
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How to use

What it does

Generate spec-compliant unique identifiers. Supports UUID v4 (random), UUID v7 (millisecond-timestamp, time-sortable) and UUID v1 (timestamp + node), plus ULID (a readable 26-character Crockford Base32 string, also time-sortable). All randomness comes from the browser native crypto.getRandomValues, which is cryptographically secure.

Example

Pick v4 with count 3 to get something like:

3f1c2b9a-7e4d-4a6b-8c2e-1f2a3b4c5d6e
a1b2c3d4-1234-4abc-8def-5566778899aa

Enable "Remove hyphens + Uppercase" to get 3F1C2B9A7E4D4A6B8C2E1F2A3B4C5D6E.

Which version?

  • v4: most common, random, no ordering
  • v7: time-prefixed, sortable by creation time, great as a DB primary key
  • v1: timestamp + node, can reveal some generation context
  • ULID: human-readable and sortable, handy for logs and storage keys

FAQ

Q1.Can a UUID v4 collide?
v4 uses 122 bits of randomness, so collisions are astronomically unlikely in practice. This tool uses cryptographically secure randomness rather than Math.random.
Q2.What is the difference between v7 and v1?
Both carry a timestamp, but v7 uses a modern millisecond layout that is naturally time-sortable and cleaner; v1 also includes a node identifier that can leak some environment context.
Q3.What is ULID?
ULID is a 26-character string: 10 chars of millisecond timestamp plus 16 chars of randomness, encoded with Crockford Base32 (ambiguous letters removed). It is sortable and easy to read.
Q4.Is anything uploaded?
No. Every identifier is generated in your browser, and the tool keeps working offline.
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