UUID Generator
Generate random v4 UUIDs — one at a time or in batches of up to 100 — using your browser's native crypto.randomUUID(). Toggle hyphens and uppercase/lowercase, copy an individual UUID or the whole batch at once. Runs entirely client-side — nothing is generated on or sent to a server.
About this tool
This tool generates random v4 UUIDs (Universally Unique Identifiers) — the standard 128-bit identifier format used everywhere from database primary keys to API request IDs to session tokens, wherever you need a value that's essentially guaranteed unique without coordinating with anything else. A v4 UUID is generated almost entirely from randomness (122 random bits, with a handful of fixed bits marking it as version 4), which is why two different generators, run at different times, on different machines, still don't collide in practice. Generate one at a time or up to 100 at once, and toggle the hyphens and letter case to match whatever format your database, API, or config file expects — those toggles just reformat the same generated values, they don't create new ones, so switching formats never changes the actual UUIDs you're looking at. It runs entirely client-side, using your browser's own native crypto.randomUUID() — nothing is generated on a server, and nothing about it is retained once you leave the page.
What you can do
- Generate 1 to 100 random v4 UUIDs at once
- Toggle hyphens and uppercase/lowercase
- Copy an individual UUID, or copy the whole batch at once
- Nothing is uploaded — every UUID is generated locally in your browser
How to use
Step 1
Set a count
Pick how many UUIDs you need, from 1 to 100.
Step 2
Adjust the format if needed
Toggle hyphens on/off and uppercase/lowercase — this reformats instantly without generating new values.
Step 3
Copy what you need
Copy one UUID at a time, or grab the whole batch with Copy all.
Example
A v4 UUID looks like this:
v4 UUID
550e8400-e29b-41d4-a716-446655440000
The "4" right after the second hyphen marks it as version 4 (random-based), and the first character of the next group is always 8, 9, a, or b — everything else is random. That structure is exactly what this tool (and your browser's native UUID generator) produces every time.
How your data is handled
This tool is labeled 🟢 Browser: every UUID is generated directly by your browser's native crypto.randomUUID() — nothing is generated on, sent to, or logged by a server. Nothing about a generated UUID is retained once you leave the page.
Frequently asked questions
How random is this, really?+
As random as your browser's own cryptographically secure random number generator (the same one behind crypto.getRandomValues(), used for things like generating encryption keys) — not a weaker Math.random()-based approximation. That's what makes v4 UUIDs collision-safe in practice.
Can two generated UUIDs ever collide?+
In theory, yes — but the probability is astronomically small (you'd need to generate roughly a billion UUIDs every second for about 85 years before hitting a 50% chance of one collision). For any practical purpose, they're unique.
What's the difference between hyphens on/off?+
Purely cosmetic — "550e8400-e29b-41d4-a716-446655440000" and "550e8400e29b41d4a716446655440000" represent the exact same UUID. Some systems (and most documentation) expect the hyphenated form; some compact storage formats or URLs prefer it stripped.
Does changing the format generate new UUIDs?+
No — toggling hyphens or case just changes how the same already-generated UUIDs are displayed. Click Generate to get an actual new random batch.
Is anything about this sent to a server?+
No — generation happens entirely in your browser via the native crypto.randomUUID() API. Nothing is uploaded, logged, or retained anywhere.