UUID Generator
Generate cryptographically secure UUID identifiers. Supports v1 (timestamp) and v4 (random).
a49eb542-e64d-44ac-a3ba-c098b17efa3eVUUID Validator
?Tips
- UUID v4 uses 122 random bits from your browser CSPRNG (cryptographically secure).
- UUID v1 uses the current timestamp, providing chronological ordering at the cost of some privacy.
- Generate up to 100 UUIDs at once for batch operations.
- Use the "No Dashes" format for compact storage in databases.
- Press Cmd+Enter to regenerate.
Understanding UUIDs
A UUID (Universally Unique Identifier) is a 128-bit value designed to be globally unique without central coordination. The standard format uses 32 hex characters in five groups (8-4-4-4-12) separated by hyphens, with specific bits indicating version and variant.
UUID v4 uses cryptographically secure random numbers for 122 of its 128 bits (6 bits are reserved for version and variant markers). The collision probability is negligibly small: generating one billion UUIDs per second for 86 years gives less than 50% chance of a single duplicate.
UUID v1 embeds a timestamp and MAC address, providing chronological ordering. This can be useful for database indexing as sequential IDs create less B-tree fragmentation. However, the embedded MAC address raises privacy concerns, so our implementation uses random node values.
In distributed systems, UUIDs solve the problem of generating unique identifiers without a central authority. They are used as database keys, API resource IDs, distributed tracing correlation IDs, uploaded file names, and idempotency keys.
UUID v7 (RFC 9562) is a newer version that embeds a timestamp prefix, making UUIDs chronologically sortable. This improves database index performance compared to random v4 UUIDs, which cause B-tree fragmentation.