Every UUID is built locally with the browser's Web Crypto random number generator, so nothing is uploaded and the tool works offline once the page has loaded. Choose version 4 when you just need an unpredictable random ID, or version 7 when the IDs will be database keys: v7 starts with a 48-bit creation timestamp, so rows insert in order and B-tree indexes stay fast. A v7 batch generated here is even strictly sorted within the same millisecond, using the monotonic counter method from RFC 9562. Flip the output to uppercase or strip the hyphens if your database or spec stores UUIDs as 32 plain hex digits.
Free UUID Generator (v4 & v7)
Runs entirely in your browser - no upload, no sign-up.
Version
Fully random - 122 bits from a secure random source.
Format
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What is a UUID generator?
A UUID generator creates universally unique identifiers - 128-bit values written as 36 characters of hex and hyphens, like 550e8400-e29b-41d4-a716-446655440000. This tool builds random version 4 and time-ordered version 7 UUIDs per RFC 9562, in bulk, entirely in your browser, so the IDs never leave your device.
How to use
- 1Pick a version. Choose UUID v4 for fully random IDs, or UUID v7 for time-ordered IDs that sort by creation time.
- 2Set the quantity. Choose how many UUIDs to generate at once, from 1 up to 1000.
- 3Adjust the format. Keep the standard lowercase hyphenated form, or switch on Uppercase or turn off Hyphens to match how your system stores IDs.
- 4Copy what you need. Click Copy on any single UUID, or Copy all to grab the whole batch, one per line.
Who it's for
- Backend developers minting primary keys, request IDs and idempotency keys - v7 for insert-ordered database keys, v4 for unguessable tokens.
- Database engineers comparing v4 and v7 behaviour before choosing a key strategy for Postgres, MySQL or MongoDB.
- QA and data engineers seeding fixtures, mock records and test payloads with a batch of valid UUIDs in one click.
- API and integration developers filling in correlation IDs, trace IDs and message keys while testing webhooks and queues.
- Anyone writing config or docs who needs a quick valid UUID without opening a terminal or installing a package.
FAQ
Is the UUID generator free?
Yes, it is completely free with no sign-up and no limits. Every UUID is generated in your browser, so you can create as many batches of up to 1000 as you like, even offline once the page has loaded.
Are the generated UUIDs uploaded anywhere?
No. UUIDs are built locally with the Web Crypto API in your browser and nothing is sent to a server, so identifiers you generate for private systems stay on your device.
What is the difference between UUID v4 and v7?
v4 is 122 random bits - maximum unpredictability, no structure. v7 replaces the first 48 bits with a Unix millisecond timestamp, so IDs sort by creation time. Use v7 for database keys that benefit from ordered inserts, and v4 when IDs must not reveal anything.
Can two UUIDs collide?
In practice, no. With v4's 122 random bits you would need to generate about 330 quadrillion UUIDs before even a 1% chance of one duplicate. This tool also uses the browser's cryptographically secure random source, not a weak pseudo-random one.
Why do UUIDs have 36 characters and hyphens?
A UUID is 128 bits written as 32 hexadecimal digits, grouped 8-4-4-4-12 by four hyphens for readability - 36 characters in total. Many systems store just the 32 hex digits; the Hyphens switch gives you that compact form.
Can I get the timestamp back out of a UUID v7?
Yes. The first 12 hex digits of a v7 UUID are its 48-bit Unix millisecond timestamp. When you generate v7 IDs here, the tool decodes that embedded timestamp and shows it under the batch in UTC.
Is a UUID the same as a GUID?
Yes. GUID (globally unique identifier) is Microsoft's name for the same 128-bit format; UUID is the vendor-neutral term standardised in RFC 9562. Any UUID generated here is a valid GUID, though Microsoft tooling often displays GUIDs in uppercase.
Are uppercase and lowercase UUIDs equivalent?
Yes. RFC 9562 says the hex digits are case-insensitive, with lowercase as the canonical output form. The Uppercase switch only changes how the ID is displayed and copied - it is still the same UUID.