Whether you are seeding a database, creating API test fixtures, or assigning IDs in an offline-first app, UUIDs give you unique identifiers you can generate anywhere without a central counter. This tool creates cryptographically random v4 UUIDs in bulk.
What a UUID looks like
A standard UUID is 36 characters: 32 hexadecimal digits split into five groups — 8-4-4-4-12 — like 550e8400-e29b-41d4-a716-446655440000. The "4" in the third group marks it as version 4 (random).
When to reach for a UUID
- Distributed systems — every node generates IDs independently, no coordination needed.
- Client-generated records — create an ID before the server exists or the network responds.
- Merging datasets — records from several sources keep globally unique keys.
- No info leakage — sequential IDs reveal how many records exist; UUIDs do not.
How to generate UUIDs online
Set the count (1 to 100), choose whether you want uppercase letters and whether to keep the hyphens, then click Generate. Copy the whole list with one button. Generation uses crypto.randomUUID() or an equivalent cryptographic fallback, so the identifiers are strong enough for production use and are created entirely on your device.
UUID v4 vs other versions
v4 is random. v1 mixes in the MAC address and timestamp, and v7 embeds a timestamp in the random structure for time-sortable IDs. For most application records v4 is the default, and this generator specialises in it.