UUID Generator

What is the UUID Generator?

A UUID (universally unique identifier), also called a GUID, is a 128-bit value written as 32 hexadecimal digits in five groups, such as 550e8400-e29b-41d4-a716-446655440000. Because the space is so large, systems can generate identifiers independently, without a central authority, and still avoid collisions in practice.

Version 4 UUIDs are built from random numbers: 122 of the 128 bits are random, the rest mark the version and variant. Version 7 (RFC 9562) places a millisecond Unix timestamp in the first 48 bits followed by random data, so values sort by creation time, which makes them friendlier to database indexes than fully random v4 keys.

When to use the UUID Generator

Generate UUIDs when you need unique values for test data, database seeds, API idempotency keys, correlation IDs in logs, file names for uploads, or primary keys that should not reveal how many rows exist. They are convenient for distributed systems because each service can create identifiers without coordinating with a central database. For fixtures, generate a batch, copy the list and paste it straight into a SQL script or JSON file instead of inventing fake identifiers that might collide with each other.

How to use the UUID Generator

1. Select the number of UUIDs you need, from 1 up to a few hundred.
2. Choose version 4 (random) or version 7 (time-ordered).
3. Toggle uppercase or remove hyphens if your system expects a different format.
4. Press Generate.
5. Copy a single value or the whole list, one per line.

Examples

v4:  3b241101-e2bb-4255-8caf-4136c566a962
v7:  018f3a6e-7c2d-7b1e-9a43-5d6f0c1e8a27
v4 (no hyphens, uppercase):  3B241101E2BB42558CAF4136C566A962

Note the third group of a v4 UUID always starts with 4 and the version 7 value starts with 7.

Common errors and tips

• Use UUIDs as public identifiers when you do not want sequential numbers to reveal how many records exist.
• For primary keys on large tables, prefer v7: sequential prefixes reduce index fragmentation.
• Store UUIDs in a native uuid or BINARY(16) column rather than a 36-character string to save space.
• Compare UUIDs case-insensitively; uppercase and lowercase represent the same value.
• A UUID is an identifier, not a secret. Do not use it as a password reset token on its own.

Privacy: runs entirely in your browser

Values are produced with the browser's secure random generator (crypto.getRandomValues) and never leave your device or get logged. This tool runs entirely in your browser: nothing you enter is uploaded, stored or logged on our servers, and it keeps working even if you go offline after the page has loaded.