UUID Generator

A UUID (Universally Unique Identifier) is a 128-bit identifier formatted as 32 hexadecimal digits in 5 groups separated by hyphens (e.g., 550e8400-e29b-41d4-a716-446655440000). UUIDs are used as database primary keys, API resource identifiers, session tokens, distributed system correlation IDs, and file names that must be globally unique. The key advantage is that UUIDs can be generated independently on any machine without a central authority and are virtually guaranteed to be unique — the probability of collision for UUID v4 is astronomically low (1 in 2^122).

UUID v4 is randomly generated using 122 random bits, making it unpredictable but unordered. UUID v7 (RFC 9562, 2024) embeds a Unix timestamp in the first 48 bits followed by random bits, making it both unique and time-sortable. UUID v7 is better for database primary keys because its time-ordering means sequential inserts maintain B-tree index locality, dramatically improving write performance in PostgreSQL, MySQL, and other databases. UUID v4 is better when unpredictability matters, like security tokens. For most new applications, UUID v7 is the recommended choice.

Theoretically yes, but practically no. UUID v4 uses 122 random bits, giving 5.3 × 10^36 possible values. To have a 50% chance of one collision, you would need to generate approximately 2.7 × 10^18 UUIDs — that is 2.7 quintillion. Generating one billion UUIDs per second, it would take 86 years to reach that threshold. For all practical purposes, UUID v4 collisions do not happen. However, the randomness quality depends on your system's cryptographic random number generator (CSPRNG). DevBolt uses the Web Crypto API which provides cryptographically strong randomness.