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
Curious about the newer time-ordered version? Read: UUID v4 vs. v7
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.