UUID Generator
Generate UUIDs (v4, v7, or nil) — one at a time or in bulk. Click any UUID to copy it.
UUID or auto-increment? Which should you use? Read: UUID vs. Auto-Increment ID
Need to generate one in code instead? Read: How to Generate a UUID in JavaScript, Python, and SQL
How it works
Generation uses the Web Crypto API's cryptographically secure random number generator, entirely in your browser, and supports v4 (fully random), v7 (timestamp-ordered), v1, and the all-zero nil UUID — individually or in bulk.
When you’d use this
- Seeding test data or fixtures that need unique identifiers
- Creating primary keys for a new table in a distributed system with no central sequence
- Generating a batch of IDs for a system where sequential, guessable IDs would be a problem
Common questions
What's the difference between UUID v4 and v7?+
v4 is fully random. v7 embeds a timestamp in the first part of the UUID, which means v7 UUIDs sort chronologically by creation order — useful for database primary keys where you want insert order to match ID order, improving index performance.
Can two generated UUIDs ever collide?+
Practically, no. A v4 UUID has 122 random bits, giving roughly 5.3×10^36 possible values — you'd need to generate billions of UUIDs per second for trillions of years before a collision became statistically likely.
What is the nil UUID used for?+
The nil UUID (all zeros) is a reserved special value meaning "no UUID" or an explicitly unset ID — used as a placeholder or default value in some systems, not for actual unique identification.
Are these UUIDs generated using a secure random source?+
Yes — crypto.randomUUID(), the browser's built-in method backed by a cryptographically secure random number generator, not a weaker pseudo-random source.