Developer tools
UUID generator
Generate random UUID v4 and ULID identifiers in bulk and copy them with one click. They are drawn from the secure Web Crypto RNG. Everything runs in your browser - nothing is uploaded.
How it works
Generate identifiers on demand, in the format you need. UUID version 4 is the standard random identifier - 122 random bits written as 32 hexadecimal digits in the familiar 8-4-4-4-12 grouping - so the chance of two ever colliding is astronomically small. ULID is a newer alternative that packs a millisecond timestamp into the first part of the value, which means ULIDs sort in roughly the order they were created while staying just as unique and URL friendly.
Every value here is drawn from the Web Crypto random number generator, the same cryptographically secure source used for keys, never the predictable Math.random. Set how many you want and generate a whole batch at once, one per line, ready to copy with a single click. Options let you uppercase the output or drop the hyphens from UUIDs to suit a column name, a filename, or an API. Everything runs in your browser, so nothing is generated on a server and nothing is sent anywhere.
Example. Pick UUID v4 and a count of 5, hit Generate, and you get five lines like 3f2504e0-4f89-41d3-9a0c-0305e82c3301, each independent and random. Switch to ULID and the values start with the current timestamp, so a batch generated together shares a common prefix and sorts in creation order, for example 01ARZ3NDEKTSV4RRFFQ69G5FAV.
FAQ
What is a UUID version 4?
A UUID is a 128-bit universally unique identifier. Version 4 fills almost all of those bits with random data (122 random bits, with 6 reserved to mark the version and variant), then writes them as 32 hex digits grouped 8-4-4-4-12. Because there are so many possible values, you can generate them independently on different machines without coordination and effectively never get a collision.
What is the difference between a UUID and a ULID?
Both are 128-bit unique identifiers, but a ULID encodes a 48-bit millisecond timestamp in its first characters and fills the rest with randomness, then writes the whole thing in Crockford base32 (26 characters, no hyphens). That makes ULIDs lexicographically sortable by creation time and a little shorter, while a UUID v4 is fully random with no ordering. Use a ULID when you want time-ordered keys, a UUID v4 when you just need randomness.
Are these identifiers random and safe to use as keys?
Yes. The random bits come from the Web Crypto getRandomValues generator, a cryptographically secure source, not Math.random, so the output is unpredictable and well distributed. That makes them suitable as database keys, request IDs, or filenames. They are identifiers, not secrets, so treat them as public values rather than as passwords or tokens.
Is anything sent to a server?
No. Generation happens entirely in your browser. Nothing is requested from a server and none of the values you generate are uploaded, logged, or stored, so the tool keeps working offline once the page has loaded.