Generate unique UUID v4 identifiers online. Bulk UUID creation for databases and APIs
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Validate UUID
UUID v4 is a universally unique identifier based on random numbers.
Used in databases, APIs, and distributed systems to create unique keys without a central coordinator.
The probability of a collision (two UUIDs matching) is extremely low — practically impossible.
UUID Generator Online — Create and Validate Unique Identifiers
UUID (Universally Unique Identifier) is a 128-bit identifier guaranteeing uniqueness without a central coordinator. The collision probability for v4 UUID is less than 1 in 2122. Our tool generates UUID v4, validates existing numbers, and detects version/variant.
UUID Versions
| Version | Generation Basis | Use Case |
|---|---|---|
| v1 | Timestamp + MAC address | Chronological sorting, distributed systems |
| v4 | Random numbers | Most popular — DBs, APIs, tokens |
| v5 | SHA-1 of namespace + name | Deterministic ID from name |
| v7 | Timestamp (ms) + random | New standard — sortable like v1, no MAC |
UUID Format
Standard: xxxxxxxx-xxxx-Mxxx-Nxxx-xxxxxxxxxxxx, where M = version, N = variant. The validator identifies version and variant and color-codes each part.
UUID vs Auto-increment
| Parameter | UUID v4 | Auto-increment |
|---|---|---|
| Uniqueness | Global | Single table only |
| Size | 16 bytes | 4–8 bytes |
| Predictability | Cannot guess | Sequential — easy to enumerate |
| Index performance | Worse (random inserts) | Better (sequential) |
| Data merge | No conflicts | Requires remapping |
Frequently Asked Questions
Can UUIDs collide?
Theoretically yes, but probability is negligible. For UUID v4, ~50% collision probability requires generating 2.71 × 1018 identifiers.
Which UUID for databases?
For PostgreSQL: v7 (sortable, better index performance) or v4 (maximum randomness). For MySQL: v7 or ULID.
Can UUID be used as a password?
UUID v4 has 122 bits of entropy — sufficient for one-time tokens. For passwords, use the password generator.
Why validate UUIDs?
The validator checks format, determines version (v1–v7) and variant (RFC 4122, NCS, Microsoft).
For hash generation use the Hash generator.
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