UUID Generator
v4 random, cryptographically secure
1
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click Generate
Collision chance is negligible
UUID v4 has 122 bits of randomness. To expect a single collision you'd need to generate 2.71×10¹⁸ UUIDs — roughly 139 years of generating 1 billion per second. Use them as primary keys, session IDs, and trace IDs without fear.
Related tools
UUID versions
- v1: timestamp + MAC address — often leaks hardware info, avoid in 2025
- v3, v5: name-based (MD5/SHA-1 of namespace + name) — deterministic, useful for content-addressed storage
- v4: pure random — most common, this generator's flavour
- v6, v7, v8 (2024 RFC 9562): timestamped for DB index-friendliness; v7 preferred for new apps
Used by: PostgreSQL uuid type, MySQL UUID(), MongoDB ObjectID alternative, Session cookies, Distributed trace IDs, wire formats, file uploads.