UUID Generator
Generate UUID v4 (Universally Unique Identifier) values. Cryptographically secure, generated in your browser. Bulk generate 1–20 UUIDs. Use with Password Generator or Base64 for developer workflows.
1–20 per batch. Version v4 (random).
Generated locally in your browser. Version v4.
What is a UUID?
A UUID (Universally Unique Identifier) is a 128-bit identifier that is virtually guaranteed to be unique across time and space. UUIDs are commonly used as primary keys in databases, session identifiers, transaction IDs, and unique identifiers in distributed systems where you need to generate IDs without coordinating with a central authority.
This tool generates UUID version 4 (random). Each UUID is created from cryptographically secure random numbers in your browser via crypto.randomUUID. Your data never leaves your device during generation.
Common uses:
- Database keys — Primary keys, foreign keys, and unique constraints in SQL and NoSQL databases.
- Distributed systems — Generate IDs across multiple servers without coordination (e.g. event IDs, job IDs).
- APIs and tokens — Unique identifiers for resources, sessions, or temporary access tokens.
- File and object storage — Unique names for uploaded files or S3-style object keys.
UUID Generator FAQ
What is UUID v4?
UUID v4 is a randomly generated 128-bit identifier. Unlike v1 (time-based) or v5 (name-based), v4 uses random numbers, making it suitable when you need unpredictable IDs. The format is xxxxxxxx-xxxx-4xxx-yxxx-xxxxxxxxxxxx where the 4 indicates version 4.
Is this UUID generator secure?
Yes. UUIDs are generated in your browser using crypto.randomUUID, which provides cryptographically secure random values. Generation happens locally—no data is sent to our servers unless you use the Share feature.
Can I generate multiple UUIDs at once?
Yes. Use the "How many UUIDs" field to generate 1–20 UUIDs per batch. Each UUID is independently random. Bulk generation is useful when you need many IDs for database seeding or batch jobs.
What is the collision probability?
For UUID v4, the probability of generating two identical UUIDs is astronomically low (about 1 in 2122). You would need to generate billions of UUIDs per second for millions of years to have a meaningful chance of a collision.
Should I use UUID or auto-increment for database keys?
UUIDs are better when you need IDs before insert (e.g. client-generated), when merging data from multiple sources, or in distributed systems. Auto-increment is simpler and more compact when you have a single database and don't need pre-generation.
Is my data stored when I use Share?
Only when you click "Copy link" after generating: the generated UUID(s) are saved temporarily (about 24 hours) to create a shareable URL. We do not store UUIDs for any other use.