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UUID Generator

What is a UUID Generator?

A UUID (Universally Unique Identifier), also called a GUID (Globally Unique Identifier), is a 128-bit identifier standardised in RFC 4122. It's formatted as 32 hexadecimal digits in five groups: xxxxxxxx-xxxx-xxxx-xxxx-xxxxxxxxxxxx. UUID version 4 (v4) is randomly generated — the probability of two v4 UUIDs colliding is astronomically small (you'd need to generate 2.7 quintillion UUIDs before having a 50% chance of a collision). UUIDs are used everywhere identifiers need to be unique without central coordination: database primary keys, session IDs, file names, API request IDs, distributed system message IDs, and correlation IDs for logging.

How to Use the UUID Generator Tool

  1. Click 'Generate' to create a new UUID v4.

  2. Use 'Bulk Generate' to create multiple UUIDs at once for batch operations.

  3. Click Copy to copy any generated UUID to your clipboard.

  4. All generated UUIDs are RFC 4122-compliant v4 UUIDs.

This UUID generator uses the Web Crypto API (crypto.randomUUID() or getRandomValues) for cryptographically secure random UUIDs. Runs entirely in your browser — no data is sent to any server. Generates RFC 4122 version 4 UUIDs. Useful for generating IDs for database records, mock data, API testing, and distributed systems.

Frequently Asked Questions

What is the difference between UUID v4 and UUID v1? UUID v1 is time-based — it incorporates the current timestamp and MAC address. This makes v1 UUIDs sortable by creation time but potentially reveals the generating machine's MAC address. UUID v4 is entirely random — no information about when or where it was generated is encoded. Use v4 for most applications; use v7 (time-ordered random) for new database primary keys.

Can I use UUIDs as database primary keys? Yes, UUIDs are widely used as primary keys, especially in distributed systems where auto-increment integers would conflict across servers. The trade-off: UUID primary keys are larger (16 bytes vs 4–8 bytes for integers) and random v4 UUIDs cause index fragmentation in B-tree indexes. UUID v7 (time-ordered) solves the fragmentation issue.

Are UUIDs truly unique? In practice, yes. The theoretical probability of generating a duplicate UUID v4 is so small it's safely ignored for all practical applications. The chance of collision when generating 1 trillion UUIDs is still about 1 in 2 billion.

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