Meta Tag Generator

What Is a UUID? A UUID (Universally Unique Identifier) is a 128-bit label used for unique identification in computer systems. UUID v4, the most common version, is generated from random numbers, making each UUID practically unique — the probability of a duplicate is approximately 1 in 5.3 × 10³⁶. ## When to Use UUIDs - **Database primary keys**: UUIDs prevent ID collisions across distributed systems, unlike auto-incrementing integers. - **API resource identifiers**: REST and GraphQL APIs use UUIDs to uniquely identify resources without sequential guessing. - **Session tokens**: Random UUIDs provide unique session identifiers that are resistant to prediction. - **File names**: UUID-based filenames prevent collisions when users upload files with the same name. - **Event tracking**: Distributed systems use UUIDs to correlate events across services without centralized coordination. ## UUID vs Auto-Increment IDs | Feature | UUID | Auto-Increment | |---------|------|----------------| | Uniqueness | Global | Per-table | | Guessable | No | Yes | | Size | 36 chars | 4-8 bytes | | Index performance | Slower | Faster | For most modern applications, UUIDs are preferred for their global uniqueness and security benefits. Use our Password Generator for security keys and our Base64 Encode tool for compact encoding.