UUID Generator

A UUID is a 128-bit identifier written as 32 hexadecimal digits in five hyphenated groups. The point of it is that two systems can each invent identifiers forever without ever agreeing on a scheme and still not collide. That makes UUIDs the usual choice for primary keys in distributed systems, for file names, for request identifiers in logs and for anything generated on a client before it reaches a server.

This generator produces version 4 UUIDs, which are random apart from the few bits that record the version and variant. Randomness comes from your browser's cryptographic random number generator, not from the ordinary random function, which matters whenever an identifier should be unguessable as well as unique.

You can generate up to a thousand at once and format them to suit the system that will consume them: uppercase, wrapped in braces as some Microsoft tooling expects, or stripped of hyphens for a compact 32-character string. A nil UUID of all zeros is also available, since it is the conventional placeholder for an absent value.

• Version 4 UUIDs from the browser's cryptographic randomness
• Generate between 1 and 1000 at a time
• Lowercase or uppercase output
• Optional braces, and an option to strip hyphens
• A nil UUID for use as a placeholder
• Copy or download the whole batch
• Nothing stored or transmitted

The uuid generator is used by writers, developers, students, marketers and anyone else who needs the job done once without installing software. Common cases include:

• Creating primary keys that do not depend on a database sequence
• Generating request or trace identifiers for logging
• Seeding a test database with realistic identifiers
• Naming uploaded files so two users cannot overwrite each other
• Producing an idempotency key for an API call