UUID Generator
Bulk UUID v4 & time-ordered v7 (RFC 9562), client-side
✦ What Is a UUID Generator?
A UUID is a 128-bit identifier that lets any machine mint globally unique keys without coordination, and this generator offers two real versions. Version 4 is fully random via the browser cryptographic generator, while version 7 is time-ordered, embedding the current millisecond timestamp in its first six bytes with explicit version and variant bits, so fresh values sort roughly chronologically and sit friendlier in indexed database columns. You can mint 1 to 100 at a time, flip to uppercase, strip hyphens, then copy the list or download it as uuids.txt.
Keys for rows, resources and test fixtures
- Generate five default IDs for primary keys, API resource names, idempotency keys or distributed event IDs, knowing v4 gives maximum unpredictability while v7 gives insertion-order locality for logs and time-series tables.
- Produce a hundred machine-format IDs in one click for seeding staging databases or load tests, using the no-hyphens form where a compact token is required and uppercase where a legacy system demands it.
Randomness, ordering and formatting caveats
- Version 4 values carry no time signal and scatter across indexes, which is a feature for secrecy but a cost for range scans, while version 7 values minted within the same millisecond share their timestamp prefix and differ only in random bits.
- The count clamps to the 1 to 100 range, stripping hyphens breaks the canonical segmented shape some validators require, and uppercase changes display only, never the underlying bits.
Generation uses the device cryptographic source inside the page and performs no fetches, so IDs are born locally. No generated value is transmitted, cached or seen by anyone but you.
Last updated · 2026-09-01
Version and variant bits, demystified
A UUID looks like random noise, but 128 bits carry self-describing metadata:
- The version nibble identifies the recipe — this tool generates v4: 122 truly random bits plus six version/variant marker bits.
- The variant bits lock the layout to the RFC 9562 “Leach–Salz” form every mainstream library expects.
- Newer v7 UUIDs encode a timestamp so they sort naturally in database indexes; v4 values scatter, which is fine for keys but useless for ordering.
Not all UUIDs are alike
v4 or time-ordered v7
Generate v4 UUIDs from pure randomness, or v7 identifiers whose timestamp prefix sorts naturally and plays better with database indexes under RFC 9562.
Bulk up to 100
Request anywhere from 1 to 100 identifiers in a single run, then copy the whole list or download it as a text file for seeding fixtures and test data.
Casing and hyphen control
Uppercase output suits systems that expect capital identifiers, and the no-hyphen option produces plain 32-character strings that fit legacy columns without post-processing.
Bulk generation, honestly bounded
Up to 500 at once — uniqueness comes from the 122-bit space itself, not from checking a list.
Frequently asked questions
UUID v4 vs v7 — which should I use?⌄
v4 is fully random and is the safe default. v7 embeds a millisecond timestamp in the high bits, so values sort by creation time — ideal as database primary keys because inserts stay index-friendly. Both are standardized in RFC 9562.
Can generated UUIDs collide?⌄
v4 has 122 random bits: you would need to generate about 2.7×10¹⁸ UUIDs for a 50% chance of a single collision. For practical purposes, collisions do not happen.
Are these UUIDs generated on your server?⌄
No — everything runs in your browser with crypto.randomUUID() and crypto.getRandomValues(). The list is never transmitted anywhere.
Can a UUID reveal when or where it was created?⌄
A v1 UUID can: it embeds a timestamp and frequently the MAC address of the machine that made it — a genuine privacy leak. The v4 UUIDs this tool produces carry no such information; there is nothing to reverse.