UUID Generator
Generate UUID v4 (random) identifiers instantly.
Click Generate to create UUIDs.
How to Use This Tool
- Choose the options or parameters you want the UUID Generator to use, such as length, character set, or quantity.
- Click the generate button and the UUID Generator will produce a fresh result instantly.
- Copy the output to your clipboard, or click generate again for another unique result.
Common Use Cases
- Database primary keys: Backend devs use UUIDs instead of auto-increment IDs to allow client-side generation and avoid leaking row counts.
- Distributed systems: Microservices generate UUIDs locally to avoid coordinator round-trips when creating entities across nodes.
- Test fixture isolation: QA engineers tag test data with fresh UUIDs so parallel test runs don't collide on shared records.
Frequently Asked Questions
What's the difference between UUID v4 and UUID v7?
v4 is fully random (122 bits of entropy) but unordered, hurting B-tree index performance. v7 (RFC 9562) embeds a millisecond Unix timestamp in the first 48 bits, so v7s sort chronologically and are friendlier to database indexes while keeping collision resistance.
What's the chance of a UUID v4 collision?
With 122 random bits, you'd need to generate about 2.71 quintillion UUIDs to have a 50% chance of a single collision (birthday paradox). For practical purposes, treat v4 collisions as impossible at any realistic application scale.
Should I store UUIDs as strings or binary in PostgreSQL?
Use the native uuid type (16 bytes binary), not varchar(36) (37 bytes plus overhead). The uuid type is 2.3x smaller, faster to compare, and indexed more efficiently. Cast to text only when displaying.