UUID Generator Online
Generate random version 4 UUIDs one at a time or in bulk.
How to use this tool
- 1Choose how many UUIDs you need.
- 2Pick formatting options such as uppercase or hyphen removal.
- 3Click Generate.
- 4Copy a single value or the whole list.
About this tool
A UUID is a 128-bit identifier that can be generated anywhere without coordinating with a central authority and still be safely assumed unique. That property is what makes it the default choice for distributed systems: two services, or an offline mobile client and a server, can each create records without any risk of colliding primary keys. Version 4 UUIDs are built almost entirely from random bits, giving a collision space so large that duplicates are not a practical concern. They also avoid the information leak of sequential integer IDs, where anyone can guess neighbouring records or estimate how many customers you have. Use them for database keys, idempotency keys on API requests, correlation IDs in logs, filenames for uploads and test fixtures.
Frequently Asked Questions
Can two UUIDs ever collide?
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Theoretically yes, practically no. The random space is large enough that collisions are not a realistic concern.
What is version 4?
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Version 4 UUIDs are generated from random data, unlike version 1 which encodes a timestamp and MAC address.
Are these generated securely?
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Yes. They use your browser's cryptographically secure random number generator and are never transmitted anywhere.