UUID v4
A random 128-bit identifier with fixed version and variant bits in a standard format.
UUID Generator
UUID v4 (Random)
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UUID v4 is a random identifier with very low collision risk
UUIDs are useful for database records, test objects, event IDs, and other values that should be unique without a central issuing service. This tool generates v4 UUIDs with cryptographic browser randomness and lets you adjust hyphens and letter case for the target system.
Key concepts
Format options
Hyphens and uppercase change representation, not the underlying identifier value.
Bulk generation
Create 1, 5, 10, or 50 IDs at once for fixtures, demos, and sample documents.
How to use
- Choose how many UUIDs to generate.
- Toggle uppercase or hyphen removal if your system expects that format.
- Generate, then copy one ID or the full list.
Frequently asked questions
Is UUID v4 guaranteed unique?
Not mathematically guaranteed, but with good randomness the collision probability is extremely low.
Is a UUID without hyphens the same value?
Usually yes; it is the same bytes in a different string format. Check what your API expects.
Can I use UUIDs as security tokens?
They are identifiers. Security tokens need separate design for entropy, expiry, storage, and authorization.
UUIDs alone are not a complete security-token or personal-identity design.