UUID Generator
Generate random version 4 UUIDs in bulk, straight in your browser. Choose how many you need, copy a single line or the whole batch, and never worry about collisions.
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NIL UUID
The reserved all-zero UUID, handy as a placeholder or a "no value" marker.
00000000-0000-0000-0000-000000000000UUID versions
Every UUID is 32 hexadecimal digits shown in five groups as 8-4-4-4-12. The 13th digit marks the version and the first digit of the fourth group encodes the variant (8, 9, a, or b for the common variant).
| Version | Description |
|---|---|
| Version 1 | Time-based, built from a timestamp and the host MAC address. |
| Version 3 | Name-based: an MD5 hash of a namespace and a name. |
| Version 4 | Random. Every digit except the version and variant is random — this is what this tool generates. |
| Version 5 | Name-based, like v3 but using a SHA-1 hash. |
UUIDs, explained
What is a UUID?+
A UUID (universally unique identifier) is a 128-bit value written as 36 characters, for example 3f2504e0-4f89-41d3-9a0c-0305e82c3301. It is designed to be unique across space and time without a central authority, so it is ideal for database keys, request IDs, and file names.
What is a version 4 UUID?+
A version 4 UUID is generated almost entirely from random data. The 13th character is always 4 (the version) and the 17th is one of 8, 9, a, or b (the variant). This tool creates v4 UUIDs using your browser’s cryptographic random generator.
Are these UUIDs random and safe to use?+
Yes. They are produced with crypto.randomUUID or crypto.getRandomValues, the same cryptographically secure source used for keys and tokens. Nothing is generated on a server and nothing you create is ever uploaded.
What is the NIL UUID?+
The NIL UUID is the all-zero value 00000000-0000-0000-0000-000000000000. It is a valid, reserved UUID used as a placeholder or a "no value" marker, similar to null. You can copy it from the reference card above.
Should I use uppercase or lowercase UUIDs?+
The standard form is lowercase, and most systems output lowercase. UUIDs are case-insensitive when compared, so uppercase is only a display preference. Use the uppercase toggle if your platform expects it.
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