UUID Generator

Data

Generate UUID v4 identifiers instantly. Bulk generation up to 50, formatting options, and one-click copy.

What is a UUID?

A UUID (Universally Unique Identifier) is a 128-bit identifier represented as 32 hexadecimal characters separated by hyphens in the format 8-4-4-4-12 (e.g., 550e8400-e29b-41d4-a716-446655440000). UUIDs are designed to be globally unique without requiring a central authority. They are used as primary keys in databases, session tokens, request IDs, correlation IDs in distributed systems, and anywhere you need a unique identifier that does not collide with other identifiers generated independently.

UUID v4 explained

UUID version 4 generates identifiers using random or pseudo-random numbers. This makes them the simplest and most widely used UUID version — no timestamp, MAC address, or namespace is needed. The randomness comes from the browser's crypto.randomUUID() method, which uses a cryptographically secure random number generator (CSPRNG). With 122 random bits, the probability of two UUID v4 values colliding is astronomically low — you would need to generate 2.71 quintillion UUIDs to have a 50% chance of a single collision.

When to use UUIDs

Use UUIDs when you need unique identifiers that can be generated independently across distributed systems without coordination. Common use cases include database primary keys (especially in multi-tenant or replicated databases), API request and correlation IDs for tracing requests across microservices, file names for uploaded assets, session tokens, and idempotency keys for payment processing. UUIDs are preferred over auto-incrementing integers when you need to hide record counts, merge data from multiple sources, or generate IDs on the client before writing to the database.

Frequently Asked Questions

Are these UUIDs truly unique?

Yes. UUIDs are generated using your browser's crypto.randomUUID() API, which uses a cryptographically secure random number generator. With 122 random bits, the probability of collision is negligible — roughly 1 in 5.3 undecillion (5.3 × 10³⁶).

What format options are available?

Four formats: lowercase (default, standard format), UPPERCASE (all caps), no dashes (32 hex characters without separators), and braces ({uuid} format commonly used in Microsoft ecosystems like C# GUIDs and Windows Registry).

Can I generate UUIDs in bulk?

Yes. Use the count slider to generate 1 to 50 UUIDs at once. Copy individual UUIDs or use the "Copy All" button to copy the entire list separated by newlines.

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