Unique identifier tool

UUID v4 generator for APIs, databases, and software testing

Create RFC 4122 UUID v4 values one at a time or in batches of up to 50, with session history.

Includes
  • UUID v4 in the standard RFC 4122 format
  • Single or batch generation (up to 50)
  • Browser cryptographic generator
  • History of the last 8 batches in the session
  • Copy of the current batch or a batch from the history
Real-time UUID

Generate unique UUID v4 values in your browser, with batches, history, and quick copy

Create identifiers with the browser's cryptographic generator, with no sign-up, and review recent batches while the page is open.

Choose between 1 and 50 UUIDs per batch.

Enter how many UUIDs to generate per batch.

Current resultno items
Session history
Generate your first UUID to start this session's history.
Summary
Fix the batch size to continue.
Current UUIDs0
Batches in history0
Maximum batch50
Who it is for
Generate unique identifiers without relying on a database
The generator is for developers, testers, and anyone preparing sample data who needs identifiers that do not repeat.
  • Create IDs for test records and sample spreadsheets.
  • Generate several UUIDs at once to fill a development database.
  • Get a quick identifier for a file, a task, or a log.
Instructions
How to use it
  1. 1. Enter how many UUIDs you want, from 1 to 50.
  2. 2. Generate the batch.
  3. 3. Copy the current batch or a batch from the history, one value per line.
  4. 4. Review previous batches in the session history.
How it works
Version 4: 122 random bits in a standard format
Each UUID is created by the browser's cryptographic generator. The format has 36 characters: 32 hexadecimal digits separated by four hyphens.
Format
xxxxxxxx-xxxx-4xxx-yxxx-xxxxxxxxxxxx
The 4 indicates the version; the y is always 8, 9, a, or b.
Chance of repetition
With 122 random bits, a repeat is so unlikely that in practice it is ignored.
That is why UUIDs can be generated in different places without coordination.
History
The 8 most recent batches stay listed while the page is open.
Reloading the page clears the history.
Verifiable example
How to recognize a UUID v4
Every UUID generated here follows the pattern below. The sample value is illustrative; the tool generates a new value every time.
Pattern
xxxxxxxx-xxxx-4xxx-yxxx-xxxxxxxxxxxx
Example
3f2b8c1e-9d4a-4b7e-a1c2-5e6f7a8b9c0d
Check the 13th character: in a UUID v4 it is always 4.
Limits
What a UUID does not guarantee
A UUID identifies; it does not protect or sort data.
  • UUID v4 values do not follow creation order; if your database needs ordering, consider other formats.
  • A UUID is not a password or access token: it must not be used as a secret.
  • The maximum batch is 50 values at a time.
FAQ
Frequently asked questions
What is a UUID v4?
It is a 128-bit universally unique identifier generated randomly according to the RFC 4122 standard.
Are generated UUIDs guaranteed to be unique?
The probability of a collision in random UUID v4 is astronomically low, making them practically unique globally.