UUID Generator
Generate unique identifiers (UUID v4)
About UUID Generator
UUID Generator lets you generate unique identifiers (uuid v4).
Category: Generators.
Frequently asked questions
What is a UUID/GUID?
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A Universally Unique Identifier (UUID) is a 128-bit number formatted as 8-4-4-4-12 hexadecimal digits (e.g., 550e8400-e29b-41d4-a716-446655440000). GUID is Microsoft's name for the same standard.
What's the difference between UUID v1 and v4?
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v1 is time-based and includes a timestamp and MAC address — it's sequential but reveals machine identity. v4 is randomly generated, preferred for privacy and most applications.
Can two UUIDs ever be the same?
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Theoretically possible, but statistically negligible. There are 2^122 (~5.3 × 10^36) possible v4 UUIDs. The probability of a collision generating one per second for a billion years is astronomically small.
Should I use uppercase or lowercase?
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RFC 4122 specifies lowercase. Most databases (PostgreSQL, MySQL) and systems accept both. Be consistent within your project.