Generate cryptographically random UUID v4 identifiers or time-sortable ULIDs in bulk. Click any result to copy it.
A UUID (universally unique identifier) is a 128-bit value written as 36 characters — five hex groups like f47ac10b-58cc-4372-a567-0e02b2c3d479. This tool generates UUID v4 (pure random), a UUID v1-like time+random hybrid, and ULIDs (time-sortable, 26 characters), one at a time or hundreds in a single batch.
It's built for developers who need stable, collision-free keys without spinning up a script. People use it to:
Every identifier is generated locally with the browser's crypto.getRandomValues RNG; nothing is uploaded, logged, or transmitted, and the tool keeps working offline once the page has loaded.
A UUID is a 128-bit universally unique identifier, written as 36 characters in five hyphen-separated hex groups (8-4-4-4-12). It's designed so anyone can generate one independently with near-zero chance of clashing with someone else's, which is why it's the go-to for distributed keys and IDs.
UUID v4 sets 6 bits to mark the version and variant, leaving 122 bits filled with pure randomness. Here those bits come from crypto.getRandomValues, the browser's cryptographically secure RNG — the same source used for keys and tokens — so the values are unpredictable, not just statistically random.
Effectively zero for normal use. With 122 random bits you'd need to generate roughly a billion UUIDs per second for about 85 years before the chance of a single duplicate reaches even 50%. You can mint them freely without a central authority checking for uniqueness.
Three: UUID v4 (122 random bits), a UUID v1-like time + random hybrid, and ULID (a 26-character, time-sortable identifier). Each can be output in lowercase or UPPERCASE using the Format tabs.
Yes. Set the Count field to any number from 1 to 500 and hit Generate to produce the whole batch at once. You can then copy every value with Copy All, or export the list as a .txt file with Download .txt.
Both. The randomness is cryptographically secure via crypto.getRandomValues, and generation happens entirely in your browser. Nothing is uploaded, logged, or transmitted, and the tool keeps working offline after the page loads.
Use UUID v4 when you want an opaque, unpredictable identifier — session tokens, public IDs, or request IDs. Reach for ULID when time ordering helps, such as database keys where newer rows clustering together improves index performance, or event IDs you want to sort chronologically without a separate timestamp.