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UUID Generator

GeneratorsFree · Private

Generate UUID v4, UUID v7, ULID, and NanoID in bulk (up to 10,000). Decode UUID timestamps, toggle formatting. 100% client-side, no server calls.

UUID variants compared

FormatLengthSortableBest for
UUID v436 charsNoGeneral-purpose random IDs
UUID v736 charsYes (ms)Database primary keys, event streams
ULID26 charsYes (ms)Compact sortable IDs, URL-friendly
NanoIDConfigurableNoShort random tokens, custom alphabet

UUID v7 — time-sortable UUIDs

UUID v7 (RFC 9562) embeds a 48-bit Unix millisecond timestamp in the most-significant bits, followed by random data. This means UUID v7 values are lexicographically sortable in creation order, which dramatically improves database index performance (B-tree pages stay sequential rather than fragmenting randomly like UUID v4).

Decoding UUID / ULID timestamps

Switch to the Decode tab to extract the embedded timestamp from a UUID v1 or v7, or from a ULID. The tool shows the millisecond timestamp and the corresponding ISO 8601 date.

Frequently Asked Questions

What is the difference between UUID v4 and v7?
UUID v4 is completely random. UUID v7 embeds a millisecond-precision timestamp in the first 48 bits, making them naturally sortable by creation time — ideal for database primary keys.
What is a ULID?
A ULID (Universally Unique Lexicographically Sortable Identifier) is a 128-bit identifier encoded in 26 characters (Crockford Base32). It is sortable like UUID v7 but more compact.
What is NanoID?
NanoID generates URL-safe IDs using a customizable alphabet and length. Shorter than UUID but cryptographically random.
How do I generate UUIDs in bulk?
Enter a count (up to 10,000) and click Generate. Bulk generation runs in a Web Worker so the UI stays responsive.

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