UUID Generator

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UUID decoder — version, variant and v7 timestamp

Paste any UUID to see which version and variant it uses. For v1, v6 and v7 the decoder also extracts the creation time embedded in the identifier and shows it as a local date and as an ISO 8601 string. Everything is decoded in your browser.

About this tool

UUIDNow is built around one idea: you usually just need one UUID, fast. So the page generates it before you touch anything — no buttons, no forms. Click the big box (or press G) and it's on your clipboard.

Every identifier comes from crypto.randomUUID() or crypto.getRandomValues() — cryptographically secure randomness built into your browser. Nothing is requested from a server, so your UUIDs cannot be logged or observed by anyone. Need sortable IDs for a database? Switch to v7, which embeds a millisecond timestamp — see the v4 vs v7 comparison, or explore more tools at dec0de.dev.

A UUID (Universally Unique Identifier) is a 128-bit value written as 36 characters like 550e8400-e29b-41d4-a716-446655440000. Because they can be generated anywhere without a central authority and effectively never collide, they are the default for database primary keys, API request IDs, idempotency keys, file names and distributed-system correlation IDs. v4 is fully random; v7 starts with a millisecond timestamp so IDs sort by creation time, which keeps database inserts sequential and indexes tidy.

Frequently asked questions

What is the difference between UUID v4 and v7?

v4 is fully random. v7 puts a millisecond timestamp at the start, so v7 IDs sort in creation order while still being highly random — which makes them better database keys.

Are these UUIDs safe to use as unique IDs?

Yes. v4 draws 122 random bits from a cryptographically secure generator, so collisions are astronomically unlikely. They are fine for primary keys, request IDs and file names.

Should I use a UUID as a database primary key?

You can. v4 keys scatter across an index and can hurt insert performance on some databases; v7’s time-ordering keeps inserts sequential, so it is usually the better choice for new schemas.

Are the UUIDs generated on a server?

No. Every ID comes from crypto.randomUUID() or crypto.getRandomValues() in your browser. Nothing is requested from or logged by a server.

What is a nil or max UUID?

The nil UUID is all zeros (00000000-0000-0000-0000-000000000000), a placeholder meaning "no value". The max UUID is all Fs. Neither is random — they are special sentinel values.