UUID generator
Generate random UUID v4 identifiers in bulk, ready to copy.
Generate 1 to 1,000 version-4 UUIDs at once, using the browser’s cryptographic generator. Uppercase and dash-removal options let you paste straight into databases, tests, spreadsheets and seeds. No identifier is generated server-side — there is no record of what you created.
What a UUID is
A UUID (universally unique identifier) is a 128-bit code used to identify records with no risk of collision — even when generated on different machines, at the same time, without central coordination. That is why databases, distributed systems and APIs use UUIDs as keys: the chance of two being equal is practically zero.
UUID v4 and bulk generation
Version 4 (v4) is the most common: based on random numbers, generated here with the browser’s cryptographic generator. You can create a single UUID or thousands at once to populate test tables or database seeds, and copy or download the whole list. Each comes in the standard hyphenated format (8-4-4-4-12).
Generated locally
All UUIDs are created in your browser, never passing through servers. For other developer test data, see the CPF & CNPJ generator and Lorem Ipsum.
Frequently asked questions
What is a UUID v4?
A randomly generated 128-bit universal identifier in the 8-4-4-4-12 format (e.g. 550e8400-e29b-41d4-a716-446655440000). The "4" marks the version: all bits are random except those flagging version and variant.
Can two UUIDs collide?
In practice, no. There are 122 random bits: generating 1 billion UUIDs per second for 85 years still leaves only a ~50% chance of a single collision. For any real application, treat them as unique.
Can a UUID be used as a password or secret token?
Ours come from crypto.getRandomValues, so they are unpredictable — but the format is predictable and some systems generate non-random UUIDs (v1 uses timestamp and MAC). For secrets, prefer dedicated tokens like those from the password generator.