UUID Generator
Generate RFC-compliant UUID v4 identifiers. Generate single or bulk UUIDs for databases, APIs, testing, and development.
Why use a UUID Generator?
Universally Unique Identifiers (UUIDs) are 128-bit identifiers that are practically guaranteed to be unique without central coordination. They're used as primary keys in distributed databases, trace IDs in logging, idempotency keys in APIs, and correlation IDs in microservices. This generator uses crypto.getRandomValues() — the same CSPRNG used for cryptographic operations — to produce true UUIDv4 values. See also our hash generator and password generator in the developer tools category.
Cryptographically random
Uses the browser's CSPRNG — not Math.random() — ensuring the random bits are suitable for security-sensitive identifiers.
Bulk generation
Generate up to 100 UUIDs at once. Useful for seeding test databases, generating batch IDs, or pre-allocating identifiers.
Multiple formats
Output in lowercase, UPPERCASE, {with braces}, or no-hyphens format to match whatever your system requires.
UUID versions compared
The RFC 4122 standard defines five UUID versions. Version 4 is the most widely used for general-purpose identifiers.
| Version | Generation method | Sortable? | Best for |
|---|---|---|---|
| v1 | Time-based + MAC address | Yes | Event logs, time-ordered records — leaks machine identity |
| v3 | Namespace + name (MD5 hash) | No | Deterministic IDs for the same input; MD5 is weak — prefer v5 |
| v4 | Random (CSPRNG) | No | General-purpose IDs, database keys, session tokens (most popular) |
| v5 | Namespace + name (SHA-1 hash) | No | Deterministic IDs from a known namespace — reproducible across systems |