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Page Utils

UUID Generator

A uuid generator creates RFC 4122 identifiers in your browser. This one mints version-4 random UUIDs by default, with optional version-1 (time-based) and the nil UUID, using the Web Crypto API so nothing is uploaded.

Press Generate and copy one UUID or a list. Version 4 uses cryptographically strong random bytes and sets the RFC 4122 version and variant bits. Version 1 encodes a Gregorian timestamp plus a random node with the multicast bit set, so it is unique in this tab without exposing a hardware MAC. The nil UUID is the all-zero id used as a placeholder in APIs. Closing the tab drops the list; we do not write UUIDs to localStorage.

UUID workspace

RFC 4122 v4
Version

Version 4 is random. Version 1 encodes a timestamp plus a random node (multicast bit set, not a hardware MAC). Nil is the all-zero placeholder.

1 to 100 identifiers. Each line is one UUID.

Output

UUIDs appear here in the browser after the page loads.

How does the UUID Generator work?

  1. 1. Choose a version

    Version 4 is the default random UUID. Switch to version 1 for a time-based id, or nil for the all-zero placeholder. Generation uses the Web Crypto API in this tab.

  2. 2. Set how many to mint

    Ask for 1 to 100 identifiers. Each line in the output is one UUID. Hyphens and uppercase only change the display; they do not remint the values.

  3. 3. Generate in the browser

    Press Generate to mint a fresh list. Changing version or count also remints. Nothing is posted to Page Utils and nothing is written to localStorage.

  4. 4. Copy the output

    Copy one UUID or the whole list. Close the tab to drop the identifiers. Treat them as random ids, not as a proof of identity or a secret store.

Questions about UUID Generator

Does this uuid generator upload anything?
No. Identifiers are minted in your browser with the Web Crypto API. There is no account and no server-side generator. The list stays in this tab until you clear it or close the page. We do not write UUIDs to localStorage.
What UUID versions can I generate?
Version 4 (random) is the default. Version 1 is time-based: a Gregorian timestamp, a clock sequence, and a 48-bit node with the multicast bit set so it is clearly a random node, not a burned-in MAC. Nil is 00000000-0000-0000-0000-000000000000, the RFC 4122 placeholder. Other versions such as v3, v5, and v7 are not on this page yet.
Is a version-4 UUID unique enough for production keys?
A version-4 UUID has 122 random bits when minted with a CSPRNG. Collisions are vanishingly unlikely for ordinary app ids. Still treat a UUID as an identifier, not as a password, an API secret, or proof that a client is authentic. If you need a secret, use a dedicated secret generator and store it in a vault.
Why is the version-1 node not my MAC address?
RFC 4122 allows a random node when a host address is not available or should not be disclosed. This page always uses a random 48-bit node and sets the multicast bit, so the value cannot be mistaken for a unicast hardware MAC. The timestamp still makes sequential v1 ids sortable in this tab.
Can I generate many UUIDs at once?
Yes. Set How many to a number from 1 to 100. Output is one UUID per line so you can paste into a spreadsheet or a seed file. Hyphens and uppercase are display options; Generate mints a new list. Closing the tab drops the output.
Do you store the UUIDs I generate?
No. Hosting logs may show that you requested this URL; they do not contain the identifiers. This is the same privacy rule as JSON Tidy on this hub. JWT Token Decrypt stays ad-light separately because it handles keys; this uuid generator is not a secret tool.

What else can I open?

These tools run in your browser. Page Utils does not store, upload, or write to localStorage the keys, tokens, or text you paste. Results are a convenience aid, not legal, tax, or security advice.