UUID Generator
Generate UUID v1, v3, v4, v5, v6 and v7, plus ULID, NanoID and MongoDB ObjectId — in batches, in the exact shape your code expects, without a single network request.
122 bits of entropy from the browser's cryptographic random source. The default when you just need something unique.
Nothing has been generated yet. Choose a type, set the amount and press Generate.
How it works
Pick a flavour
Eleven of them, from plain v4 to time-ordered v7, ULID or a Mongo ObjectId.
Set the batch
How many, and in what shape: case, hyphens, wrapping, prefix, export format.
Press generate
Nothing runs until you do. The batch is built in a worker and timed to the tenth of a millisecond.
Take it with you
Copy, download as txt, csv, json or SQL, or send the list straight to another tool.
Eleven identifier types
UUID v1, v3, v4, v5, v6, v7, nil and max, plus ULID, NanoID and MongoDB ObjectId.
Time-ordered and monotonic
v7, v6 and ULID keep a counter, so identifiers minted inside the same millisecond still sort in creation order.
Reads them back
Paste any identifier to see its version, variant, timestamp, node and raw bytes — then edit a single nibble.
Off the main thread
Batches run in a Web Worker, with the exact generation time and a duplicate sweep over the whole batch.
Output the way you need it
Case, hyphens, braces, urn:uuid:, quotes, prefix and suffix — exported as txt, csv, json or SQL.
Nothing leaves the tab
Web Crypto entropy, no network call of any kind, and nothing kept between visits.
Every identifier format, generated locally
Most generators give you a v4 and stop there. This one covers the whole RFC 9562 family, the sortable formats that replaced it in practice, and the identifiers other ecosystems use — with the output shaped exactly the way your migration, seed file or test fixture needs it.
Sortable by construction
Random v4 keys scatter writes across a B-tree index. v7, v6 and ULID put the timestamp first, so new rows land at the end of the index instead of everywhere at once — and this tool keeps a counter inside each millisecond so the order holds even in a tight loop.
Built for the work that comes after the identifier
Generate a hundred thousand keys, export them straight as a SQL INSERT or a JSON array, and hand the list to the diff, hash or archive tool without touching your downloads folder.
Entropy comes from the Web Crypto API inside your tab. There is no API call, no CDN fetch and no WebAssembly download: the hashing used by v3 and v5 is embedded in the page itself, so the tool works with the network switched off.
Frequently Asked Questions
QWhich UUID version should I use?+
v4 when you just need uniqueness and nothing else. v7 when the identifier becomes a database primary key, because its leading timestamp keeps index writes local. v5 when the same input must always map to the same identifier.
QWhy does asking for ten v5 UUIDs give me ten identical ones?+
Because that is what v5 means: one namespace plus one name always hashes to one identifier. If you need ten different ones, give it ten different names — one per line.
QWhat is the difference between v7 and ULID?+
Both are a 48-bit millisecond timestamp followed by randomness. v7 is a real UUID and fits a UUID column; ULID is 26 base32 characters, shorter to read and case-insensitive, but not a UUID.
QAre these identifiers cryptographically secure?+
The randomness comes from crypto.getRandomValues, the same source the browser uses for its own key material. Note that a v1 or v7 identifier deliberately exposes its creation time, so it is not a secret.
QHow many can I generate at once?+
Up to 100 000 per batch. The on-screen list shows the first 300 rows so the page stays responsive; copy, download and the handoff buttons always work on the complete batch.
QDoes anything get sent to a server?+
No. Generation, inspection and export all happen in your browser, and the page makes no request while you use it.