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UUID Generator

Generate RFC 4122 compliant v4 UUIDs instantly — single or in bulk. Choose from 5 output formats and copy everything to your clipboard in one click.

Freev4 UUIDsBulk Export5 Formats

Options

Output Format

Separator (when copying all)

Quantity

5 UUIDs (v4)

  • 19a8cbc5-ec65-4b33-b0d5-980973b31f36
  • 6181b22f-63f9-4ebf-8614-68eba7c93644
  • 7ac11b7d-b263-4867-b953-87a06fe1facd
  • ff645324-bf8d-4b80-a749-ae3b30742759
  • e9ceddf4-1a29-46dd-b9f0-8b7d81037f42
UUIDs are generated using crypto.randomUUID() — a cryptographically secure browser API. All v4 UUIDs are statistically unique.

What are UUIDs used for?

UUIDs are used as primary keys in databases, session identifiers, file names, API resource IDs, and anywhere you need a unique identifier without a central authority assigning them. They are safe to generate client-side because the collision probability is practically zero.

UUID v4 vs other versions

v1 encodes the MAC address and timestamp — unique but leaks system info. v3 and v5 are namespace-based hashes (MD5 and SHA-1) — deterministic from input. v4 is fully random — the best choice for most use cases. v7 (newer) encodes a timestamp prefix for database index performance; not yet universally supported.

Output format guide

  • Standard: lowercase with hyphens — most databases, REST APIs.
  • Uppercase: same as standard but uppercase — older Windows systems.
  • No hyphens: 32 hex chars — MySQL CHAR(32), compact storage.
  • Braces: surrounded by curly braces — C#, .NET, COM objects.
  • URN: urn:uuid: prefix — XML, RDF, semantic web.