UUIDs Generator
Generate standards-compliant UUIDs - version 4 (random) or version 7 (timestamp-ordered) - individually or in bulk.
Recommended Settings
Pro Tips
- •Version 4 UUIDs are fully random, while version 7 UUIDs embed a millisecond timestamp, so they naturally sort in creation order - useful as database primary keys for better index locality
- •Both versions carry 122 or more random bits, making collisions astronomically unlikely for any practical use
- •Version 7 is a newer standard (finalized in RFC 9562) that many databases now recommend over v4 specifically because sequential keys reduce index fragmentation
- •Generate up to 100 at once and copy them all as a newline-separated list
Most Popular
Most developers now default to version 7 for new database primary keys, keeping version 4 for general-purpose random identifiers
When to Use This Tool
Generate unique identifiers for database records, especially version 7 for better index performance.
Create realistic unique IDs for test fixtures and database seed data.
Generate unique IDs across distributed systems without central coordination.
Create unique request or trace IDs for logging and debugging.
How It Works
For version 4, fill all 16 bytes with cryptographically random data, then set the required version and variant bits
For version 7, embed the current millisecond timestamp in the first 6 bytes, fill the rest randomly, then set the version and variant bits
Format the result as a standard 8-4-4-4-12 hex string
100% Private
Files never leave your device. All processing happens locally in your browser.
Lightning Fast
Powered by Web Crypto API (crypto.getRandomValues), RFC 9562 UUID formats for optimal performance on modern browsers.
Open Source
Built with verified, open-source libraries. Fully transparent.
Frequently Asked Questions
What's the difference between v4 and v7?
Version 4 is entirely random, while version 7 embeds a timestamp in its first bits, causing UUIDs generated later to sort after ones generated earlier - useful for database indexes that benefit from roughly sequential keys.
Are these guaranteed unique?
Not mathematically guaranteed, but with well over 60 bits of randomness in every UUID, the probability of a collision is negligible for virtually any practical application.
Can I use v7 UUIDs in production?
Yes, version 7 is a finalized IETF standard (RFC 9562) and is increasingly recommended by database vendors specifically for primary key use.
Is my data sent to a server?
No. Every UUID is generated entirely in your browser.
Does a v7 UUID reveal exactly when it was created?
Yes, the embedded timestamp is visible to anyone who decodes it, which is worth considering if you don't want creation timing exposed through your identifiers.