Generate unique UUIDs (v4) for IDs, tokens, and database keys.
IDs · UUID v4 · test data
Generate random UUID version 4 identifiers in bulk, entirely in your browser. Use them for database seeds, request correlation ids, demo fixtures, and any place you need unique ids without a central counter.
A UUID (Universally Unique Identifier), also called a GUID in Microsoft ecosystems, is a 128-bit value usually written as 32 hex digits with hyphens:
550e8400-e29b-41d4-a716-446655440000Version 4 UUIDs are mostly random. Collision probability at normal application volumes is negligible — you do not need a central ID server for uniqueness. UUIDs are identifiers, not secrets: guessing resistance is not the same as authentication. Do not use a bare UUID as an API key without additional security controls.
X-Request-Id documentation examples.1,2,3 that collide across environments.| Version | Idea | Notes |
|---|---|---|
| v1 | Time + node | Can leak MAC/time metadata; less common in new apps |
| v4 | Random | Default choice for many apps; this tool |
| v5 | Name-based (SHA-1) | Deterministic from namespace + name |
| v7 | Time-ordered | Better B-tree index locality than random v4 |
If database index fragmentation from random v4 keys becomes an issue at scale, consider UUIDv7 or a time-sortable id scheme — that is an architecture choice beyond this generator.
Formatting: Some systems expect uppercase hex, others strip hyphens. Normalize consistently in your API. This tool emits the common 8-4-4-4-12 lowercase form from the browser’s UUID implementation.
In theory yes; in practice for v4 at ordinary rates the risk is astronomically low. Still use database unique constraints for critical tables.
No. Treat it as a public identifier unless you add separate authentication and authorization.
Generation runs locally in your browser. Privacy Policy.
Integers are smaller and friendly to indexes; UUIDs simplify merges and client-side id creation. Pick based on scale, privacy (sequential ids leak volume), and operational needs.