UUID Generator

A UUID (Universally Unique Identifier), also called a GUID (Globally Unique Identifier) on Windows and in .NET, is a 128-bit value typically written as 32 hexadecimal digits split into five groups by hyphens, like 550e8400-e29b-41d4-a716-446655440000. The point of a UUID isn't cleverness — it's that two systems can each generate one independently, with no coordination or central authority, and the odds of a collision are astronomically small. That makes UUIDs the default choice whenever you need a unique identifier without querying a database or a sequence generator first.

This tool generates version 4 UUIDs, the most common variant, where the bits are derived from a cryptographically secure random number generator rather than from a timestamp or a hardware address. That's what most libraries and databases mean by "UUID" unless a different version is specified, and it's the right default for primary keys, request/trace IDs, session tokens, idempotency keys, and any other place you need an opaque, collision-resistant identifier.

Everything happens locally in your browser — the random bytes are generated on your device, formatted into UUIDs, and never transmitted anywhere. That makes the generator safe to use even for values that will end up as internal identifiers in a system you don't want to expose to a third-party server, and it means the tool keeps working without an internet connection once the page has loaded.

You can generate up to 100 UUIDs at once, which is handy for seeding test fixtures, populating a spreadsheet, or grabbing a batch of IDs for a migration script. Two formatting options adjust the output to match whatever a downstream system expects: the hyphens toggle switches between the standard grouped format and a flat 32-character string with no separators, and the uppercase toggle capitalizes the hex digits for systems (some legacy .NET code, for instance) that expect GUIDs in that form.

Once you've generated a batch, use the copy button to grab the full list, or the “Send to” menu to hand a single value straight to another tool in this toolbox — for example, checking its length or feeding it into a hashing tool — without retyping anything.