UUID Generator

What is a UUID?

A UUID (Universally Unique Identifier), also called a GUID in the Microsoft world, is a 128-bit value written as 32 hexadecimal digits in five groups, such as 3f2b8c1e-9a4d-4e7b-b6a1-2c5d8e9f0a1b. UUIDs let different computers create identifiers independently without asking a central database for the next number, and the chance of two random UUIDs ever colliding is so small it can be ignored in practice.

How to generate UUIDs

1. Choose Version 4 for fully random IDs or Version 7 for time-ordered IDs.
2. Enter how many you need, from 1 to 500.
3. Pick formatting options: uppercase, no hyphens, or wrapped in braces.
4. Click Generate, then copy the list or download it as a text file.

Version 4 vs version 7

• UUID v4 contains 122 random bits. It reveals nothing about when or where it was made and is the most widely supported version.
• UUID v7, standardised in RFC 9562, starts with a 48-bit Unix timestamp in milliseconds followed by random bits. IDs created later sort after earlier ones, which keeps database indexes compact and fast.
• Within one batch, the v7 generator uses a counter so every ID in the list is in increasing order, even when many are made in the same millisecond.

Where UUIDs are used

Developers use UUIDs as primary keys in databases, as IDs for records created offline in mobile apps, as request and correlation IDs in logs, as file names for uploads and as idempotency keys for payment APIs. Testers use bulk lists to seed databases and fixtures. Version 7 is becoming the preferred choice for new database tables because it combines uniqueness with natural ordering.

Is it secure?

The random bits come from your browser’s cryptographically secure random number generator, the same source used for encryption keys. The UUIDs are generated on your device and are never sent to or stored on our server. Still, a UUID is an identifier, not a password. Do not rely on a UUID being secret to protect private data.

Tips

Store UUIDs in a native UUID or 16 byte binary column where your database supports it, rather than as 36 character text, to save space. If a system rejects your UUIDs, check whether it expects uppercase letters, braces or no hyphens, and use the formatting options to match. Hyphens are only a display convention, so the same UUID with or without them refers to exactly the same value.