Developer Tools
UUID Generator
Up to five hundred at a time, in the format your system expects.
- Runs in your browser
- Nothing uploaded
The tool
Choose how many and in what format. Generated locally by your browser cryptographic random source.
Everything you enter stays on your own machine. Nothing is sent to us or to anyone else, which you can confirm in your browser network tab.
What people use it for
- Seeding test data with realistic identifiers
- Generating primary keys before a record is saved
- Creating unguessable URLs for shared resources
- Producing correlation identifiers for request tracing
- Filling a column in bulk without writing a script
About this tool
Where the randomness comes from
This uses crypto.randomUUID where the browser offers it, and crypto.getRandomValues otherwise. Both draw on the operating system cryptographic random source. A surprising number of generators use Math.random instead, which is not cryptographically secure and produces values an attacker can sometimes predict. For a database key that rarely matters. For anything acting as a secret, a token or an unguessable URL, it matters a great deal.
Version 4, and why
Version 4 is random. Version 1 encodes the time and the network card address, which leaks when and where it was made, and version 7 encodes a timestamp deliberately so identifiers sort by creation order. Version 4 is the right default when you simply need something unique and do not want it to reveal anything.
Collisions
A version 4 UUID has 122 random bits. The chance of two colliding is small enough that it is not a practical consideration, which is the entire point: you can generate them independently on different machines with no coordination and no central authority handing out numbers.
Formats
Lowercase with hyphens is the standard and what most systems expect. Uppercase and braced forms come from Microsoft tooling. The unhyphenated form is common where the identifier goes into a URL or a filename. They are the same value; only the presentation differs.
Need this handled across a whole website? See our Backend Web Development and Custom Web Apps page.
More tools and services
- JSON Formatter and Validator
- Base64 Decoder and Encoder
- URL Encoder and Decoder
- Colour Converter and Contrast Checker
- JWT Decoder
- Unix Timestamp Converter
If you would rather someone did this properly for you, we offer Web Design Services and Website Development, SEO Services: Search Engine Optimization, AI Automation Agency.
Questions
Questions about this tool
The things clients actually want to know — costs, timelines, ownership and what happens after launch.
Version 4, which is random. That is the right default when you need uniqueness without revealing a time or a machine.
No. It uses the browser cryptographic random source, which is the difference between a value that is unique and one that is also unguessable.
With 122 random bits, a collision is not a practical concern. That is what lets separate machines generate them with no coordination.
Five hundred at a time, which keeps the page responsive. Generate again for more.
No. Everything happens in your browser.
Free strategy session
Let’s build something worth finding.
Tell us where you want the business to be in twelve months. We will come back with a costed plan, a realistic timeline, and the numbers we expect to move — no obligation, no jargon.
- 30-minute call, no pitch deck
- Fixed-price proposal in 48 hours
- You own everything we build
Talk to a developer
Not a sales team
- Response time
- Within 1 business hour
- Where we work
- UK, USA & the Gulf
- Contracts
- No lock-in, monthly rolling
- Working since
- 2023