๐Ÿ†” UUID Generator

UUID Generator โ€“ Instantly Create Unique Identifiers

๐Ÿ†” UUID Generator

Instantly create unique identifiers for databases, APIs, and distributed systems. Generate cryptographically secure UUIDs with global uniqueness guaranteed.

Instant UUID Generator

Your new UUID (v4):
Click Generate to create your first UUID
Version
v4 (random)
Length
36 characters
Format
8-4-4-4-12

Batch Generator

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100% Client-Side Generation: All UUIDs are generated in your browser using cryptographically secure random numbers. Nothing is stored or transmitted.

What is a UUID? Why Use One?

UUID stands for Universally Unique Identifier. Itโ€™s a 128-bit value, usually represented as a string of 36 characters (hex digits and dashes) like e4b2b1c8-5dcb-4c6e-8b45-00c1c31e1d0a. UUIDs are generated so that the probability of creating two identical values (collisions) is vanishingly smallโ€”even across distributed systems or millions of devices.

Did you know? The chance of generating duplicate UUID v4s is so low that youโ€™d need to generate about 2.71 quintillion UUIDs to have a 50% chance of a collision!

How UUIDs Work

  • Follow the RFC 4122 standard
  • 36 characters: 8-4-4-4-12 format
  • Version 4 uses random numbers
  • Platform-independent across languages
  • Extremely unlikely to collide

Real-World Use Cases

  • Primary keys in distributed databases
  • API tokens and session identifiers
  • Device or user identifiers
  • File IDs in cloud storage
  • Microservice resource identifiers

Best Practices

  • Use for distributed systems
  • Store as strings or binary
  • Never edit or truncate UUIDs
  • Use strong random generators
  • Consider indexing for large datasets

Common Pitfalls

  • Donโ€™t assume UUIDs are secret tokens
  • Donโ€™t use for sensitive authentication alone
  • Keep format consistent in projects
  • Always validate user input
  • Donโ€™t use for sequential ordering

UUID vs. Other ID Types

Type Example Length Collision Risk Predictable?
UUID v4 f47ac10b-58cc-4372-a567-0e02b2c3d479 36 chars Extremely low No
Auto-increment 123456789 9-12 digits High (distributed) Yes
Random String aZ8Qp1xB9m 10+ chars Low (if strong RNG) No
Hash (SHA256) a3c9eโ€ฆc8f6 64 chars Very low No

For global uniqueness, UUIDs and hashes are preferred. Auto-increment IDs are only safe in single-node databases.