UUID Generator
Generate one or multiple random UUID v4 values instantly. Copy to clipboard. Free online UUID generator, no data sent to servers.
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What is a UUID?
A UUID (Universally Unique Identifier) is a 128-bit value used to uniquely identify
information in computer systems. UUID v4 uses cryptographically random numbers and has the
format: xxxxxxxx-xxxx-4xxx-yxxx-xxxxxxxxxxxx. All UUIDs are generated in your
browser using the Web Crypto API — no data is sent to any server.
What is the difference between UUID v1 and UUID v4?
UUID v1 is generated from a timestamp and the device's MAC address, so it encodes when and where it was created. UUID v4 is generated from random numbers, making it unpredictable and privacy-friendly. V4 is the most commonly used version today.
What is a UUID used for?
UUIDs are used as database primary keys, session tokens, API request IDs, distributed system identifiers, and anywhere a unique ID is needed without a central authority to assign sequential numbers.
Can two UUIDs ever be the same?
Theoretically yes, but practically no. A UUID v4 has 122 random bits, giving about 5.3 × 1036 possible values. You would need to generate about 2.7 × 1018 UUIDs to have a 50% chance of a single collision.