A UUID (Universally Unique Identifier) is a 128-bit identifier with a practically negligible chance of collision. It's used wherever a unique ID is needed without a central authority to issue them — database records, filenames, session IDs, and more.

What's the difference between UUID v1, v4, and v7?

The different UUID versions determine how the identifier is generated: - v1 (Time-based): Uses the timestamp it was generated at plus a random device identifier; it can be generated in order but is less favored for privacy reasons. - v4 (Random): Based entirely on random numbers; the most widely used version, requiring no name, timestamp, or machine info. - v7 (Sortable): Combines a timestamp with randomness, making it both unique and sortable (monotonic). It performs better than v4 as a database primary key and became an official standard (RFC 9562) in 2024.

Which version should I choose?

It depends on your use case: - Choose v4: For general-purpose, privacy-first use — still the safest and most widely supported option. - Choose v7: If you want a sortable, performant primary key in a database. - Choose v1: Only if you need compatibility with legacy systems; it's generally not preferred today.

Can two UUIDs collide?

Theoretically yes, but in practice the chance is negligible. Versions like v4 and v7 use well over a hundred bits of randomness — even generating trillions of UUIDs, the probability of a collision remains vanishingly small.

Is my data sent to a server?

No. UUID generation happens entirely in your browser using JavaScript's cryptographically secure random number generator; nothing is sent to any server.

Tools/💻 Digital Tools/UUID Generator

UUID Generator

Generate unique UUID identifiers in v1, v4, or v7 format; create multiple at once.

Version 1.0 · Last Updated: August 3, 2026 · Maintained by ToolLarder

Version

Number of IDs

You can generate up to 50 at once.

Format

Generated IDs will appear here.

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UUID Generator

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