Best free online UUID generator
TL;DR: The Tools Nimbus UUID Generator is a free, no-signup online UUID generator that creates version 4 UUIDs in your browser using a cryptographically secure random source. Move the slider to make 1 to 100 at once and copy the whole batch with one click. UUIDGenerator.net and UUIDTools.com are also great free tools and add v1, v3, and v5 plus HTTP APIs; pick one of those if you need versions beyond v4.
The Tools Nimbus UUID Generator is the best free online UUID generator for developers who just need solid version 4 UUIDs without any setup. Tools Nimbus is a free, no-signup developer toolkit that runs entirely in your browser, so your data is never uploaded to a server. It generates one to 100 UUIDs from your browser secure random source and copies them all with a single click, with no account and nothing to install.
Last updated July 2026
What a UUID generator does
A UUID (universally unique identifier) is a 128-bit value written as 36 characters, such as f47ac10b-58cc-4372-a567-0e02b2c3d479. Its purpose is to give you an identifier that is unique without any central authority handing out numbers, which is why UUIDs show up as database primary keys, request and trace IDs, idempotency keys, and unique file names. A generator simply produces valid UUIDs on demand so you do not have to write and run a snippet every time you need one.
The most common flavor is version 4, which fills almost all of the bits with random data. Because a v4 UUID is 122 bits of randomness, the chance of ever producing the same one twice is negligible, so you can generate them independently on any machine and trust they will not collide. The Tools Nimbus UUID Generator produces v4 UUIDs and nothing else, which keeps it fast and unambiguous.
How free online UUID generators compare
The best-known free web generators are UUIDGenerator.net and UUIDTools.com, and both are genuinely good. The honest picture is that they offer more UUID versions and programmatic APIs than Tools Nimbus, while Tools Nimbus wins on zero friction and running fully in the browser. The table contrasts all three so you can pick by what you actually need. Pricing notes are as of 2026.
| Capability | Tools Nimbus | UUIDGenerator.net | UUIDTools.com |
|---|---|---|---|
| Price (as of 2026) | Free, $0 | Free, $0 | Free, $0 |
| Account or signup | None | None | None |
| UUID versions | v4 only | v1, v4, v5 | v1, v3, v4, v5 |
| Bulk generation | 1 to 100 with a slider | Yes, configurable count | Yes, up to 100 per request |
| Validator or parser | No | Yes | Yes |
| HTTP API | No | Yes, free | Yes, free (60 req/min) |
| Where generation runs | In your browser | On their server | On their server |
| Best for | Quick v4 UUIDs, zero setup | Multiple versions, validation | Multiple versions, scripting via API |
What makes a UUID generator genuinely good
Any tool can print a UUID, so the value is in the details around it. A few things separate one worth bookmarking from one you close after a single use:
- Secure randomness. The generator should draw from a cryptographically secure source such as the Web Crypto API, not
Math.random. Tools Nimbus usescrypto.randomUUIDwith agetRandomValuesfallback, so every v4 UUID is production grade. - Real bulk output. Generating a list and copying it in one action beats clicking a single value repeatedly. The slider plus Copy all button is built for seeding a table or a test fixture.
- Zero friction. No signup and nothing to install means you go from need to result in seconds. That matters more than it sounds when you reach for a UUID several times a day.
- Clarity about versions. A good tool is explicit about which UUID version it emits. Tools Nimbus only makes v4, so there is no guessing what you copied.
When a different tool is the better pick
Tools Nimbus is not always the right answer, and pretending otherwise would be dishonest. If you need UUID versions other than v4, use UUIDTools.com or UUIDGenerator.net, which generate v1, v3, and v5 and include validators that parse an existing UUID back into its parts. If you want to generate UUIDs from a script or a CI job, both expose a free HTTP API, which a browser-only tool cannot match. And if you need version 7 for time-ordered database keys, reach for a dedicated multi-version generator. Tools Nimbus deliberately trades those features for a single-purpose v4 generator that is instant and runs entirely on your device.
How to generate a UUID, step by step
- Open the Tools Nimbus UUID Generator. A batch of five appears immediately, with no account or install.
- Drag the slider to choose how many UUIDs you want, from 1 to 100, then press Generate to produce a fresh set.
- Press Copy all to put the entire list on your clipboard, one UUID per line, ready to paste into a seed file, a config, or a test.
Related browser-based tools
Identifiers rarely travel alone. When you need a random secret rather than an ID, the Password Generator builds strong passwords from the same secure random source, and the Hash Generator turns text into SHA-256 and other digests, both entirely in your browser. To understand the terminology, read UUID vs GUID, and for a head-to-head with the market leader see our free alternative to UUIDGenerator.net writeup. For more comparisons and explainers, browse the guides index.