UUID Generator
Generate random UUIDs (v4 and v7). Bulk generate up to 100 at once.
Navigation
Private by default
Files stay in your browser. Nothing is uploaded unless a tool says otherwise.
When to use this
You're spinning up a new database table and need primary keys that won't collide across servers, regions, or even completely independent systems — without any coordination. That's the entire point of UUIDs. Generate one anywhere, anytime, and you can be statistically certain it's unique across every UUID ever created. No central registry, no auto-increment sequence to manage, no distributed lock.
Beyond database keys, UUIDs show up as request IDs for distributed tracing (attach one to every API call and follow it through your logs), idempotency keys for payment APIs (Stripe requires one), file names that won't collide in object storage, and session tokens. Any time you need a unique identifier that doesn't leak information about your system's internals (unlike sequential IDs), a UUID is the standard answer.
Need a batch? The bulk generator creates up to 100 UUIDs at once — useful for seeding test data, pre-generating IDs for a migration script, or populating a staging database.
Good to know
v4 is random. v7 is time-sorted. Pick based on your use case. UUID v4 (RFC 9562) is 122 bits of pure randomness — great for general-purpose unique IDs. UUID v7 embeds a Unix timestamp in the first 48 bits, making them sort chronologically. If you're using UUIDs as database primary keys, v7 is the better choice — it avoids the random-write performance problem that v4 causes in B-tree indexes.
The collision probability is vanishingly small. With 122 random bits, you'd need to generate about 2.7 x 10^18 (2.7 quintillion) v4 UUIDs before hitting a 50% chance of a single collision. For practical purposes, it won't happen. The odds of a collision in a billion UUIDs are about 1 in 10^21.
UUID vs. GUID — same thing, different name. Microsoft calls them GUIDs (Globally Unique Identifiers), everyone else calls them UUIDs. The format is identical: 32 hex digits in 8-4-4-4-12 grouping. If a system asks for a GUID, generate a UUID.
Power user tip: the version and variant bits are fixed positions. In xxxxxxxx-xxxx-4xxx-axxx-xxxxxxxxxxxx, the "4" is the version nibble (always 4 for v4, 7 for v7) and the leading bits of the next group set the variant to RFC 9562. This means not all 128 bits are random — v4 has 122 random bits, and v7 has 74 random bits plus a 48-bit timestamp. Knowing this matters when calculating collision probabilities.
Quick Reference
| UUID Version | Based On | Sortable? | Best For |
|---|---|---|---|
| v1 | Timestamp + MAC address | Yes (with caveats) | Legacy systems (leaks hardware info) |
| v4 | Random | No | General-purpose unique IDs |
| v5 | SHA-1 hash of namespace + name | No | Deterministic IDs from known inputs |
| v7 | Unix timestamp + random | Yes | Database primary keys, time-ordered IDs |