UUID Generator
Click generate for a fresh RFC 4122 UUID. Bulk-create up to 500 at once and copy them all.
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What is a UUID, and is a GUID the same thing?
A UUID (Universally Unique Identifier) is a 128-bit value defined by RFC 4122 (updated by RFC 9562), written as 32 hexadecimal digits in five hyphen-separated groups like 550e8400-e29b-41d4-a716-446655440000. GUID (Globally Unique Identifier) is Microsoft's name for exactly the same thing, so this UUID generator doubles as a GUID generator. Because a random UUID draws from 2^122 possibilities, anyone can create one independently on any machine — no central registry — and still trust it will not collide.
UUID v4 vs UUID v7 — which one should I use?
A UUID v4 generator produces 122 bits of pure randomness — perfect as a general random UUID whenever you just need uniqueness. A UUID v7 generator produces time-ordered values: the first 48 bits are a Unix millisecond timestamp, so v7 UUIDs sort chronologically. That makes v7 ideal for database primary keys and B-tree indexes, where sequential inserts stay compact and fast instead of scattering across the index the way random v4 keys do. Choose v4 for opacity and no time leakage; choose v7 when insert locality and sortability matter.
Are these UUIDs really unique and random?
Yes. Every random value comes from crypto.getRandomValues (using crypto.randomUUID where the browser offers it) — the cryptographically secure generator built into your browser, never the predictable Math.random. With 122 random bits, the odds of two v4 UUIDs colliding are astronomically small: you would have to generate billions per second for roughly a century before a collision became likely. If a browser is too old to provide a secure generator, this tool disables itself instead of silently falling back to something insecure.
Are the generated UUIDs sent anywhere?
No. This uuid generator runs 100% in your browser — every UUID v4, UUID v7 and nil value is created locally in JavaScript, and nothing is ever uploaded, logged, or shared. That makes it safe for API keys, database rows, secrets, and test fixtures. The values are one-shot: reload the page and they are gone, because nothing is stored.
How do I generate UUIDs in bulk and copy them all at once?
Set the count to any number from 1 to 500 and click Generate to create a whole batch. Each row has its own copy button, or use "Copy all" to put the entire list on your clipboard as newline-separated lines — perfect for seeding a database, filling a test dataset, or pasting into a spreadsheet. The format toggles (Uppercase, Hyphens, and Wrap in braces) reformat the current batch instantly without regenerating, so you can match whatever your database or code expects.