What This Tool Does
UUID generation: Creates version 4 (random) UUIDs—128-bit identifiers designed to be unique across space and time. Each UUID has 32 hexadecimal digits in 5 hyphen-separated groups.
Structure: Format is 8-4-4-4-12 (xxxxxxxx-xxxx-xxxx-xxxx-xxxxxxxxxxxx) where each x is a hexadecimal digit (0-9, a-f).
Uniqueness: Generates random-looking UUID v4 values for general development and testing. The current browser function uses Math.random, so do not treat it as cryptographically secure.
Version 4: Random UUID variant—the most common type. No timestamps or MAC addresses, ideal for web apps and privacy-conscious systems.
Buttons create UUID v4 strings (8-4-4-4-12 hex) in the browser. Version and variant bits are set on the template, but random nibbles come from Math.random—fine for fixtures and demos, not for secrets or session tokens.
Output
- Generate one — single line in the textarea.
- Generate 5 — five lines separated by newlines.
- Copy — copies the textarea wholesale.
When not to use this page
Production auth, payment ids, or anything that must resist prediction should use crypto.randomUUID() or server-side CSPRNG—not this helper.
Processing
IDs are computed locally; nothing is uploaded.
UUID questions
What is a UUID?
A UUID is a Universally Unique Identifier, commonly represented as 32 hexadecimal digits separated into five hyphenated groups.
How do I generate a UUID v4?
Click Generate one or Generate 5. This page creates UUID v4 strings in the usual 8-4-4-4-12 layout. You can click again to make more.
What is a GUID?
GUID is a term often used in Microsoft ecosystems for UUID-compatible identifiers. Practical differences depend on the platform and context.
What is UUID v4?
UUID v4 is the random UUID version. It uses random bits plus version and variant markers to produce the standard UUID format.
Are UUIDs unique?
UUIDs are designed to make collisions extremely unlikely, but uniqueness depends on correct generation and is not the same as a central database guarantee.
How many UUIDs can I generate?
The current interface generates one UUID or five UUIDs at a time. You can click again to create more.
Which UUID version should I use?
Use UUID v4 when you need random identifiers without embedded time or machine information and your system accepts that format.
Related Developer
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