Everything here is made for a machine to read
What unites this category is that you are almost never the consumer of the output. A scanner reads the barcode, a phone camera reads the QR code, a database indexes the UUID, a browser renders the colour. So the question that matters for every tool here is the same one: will the thing that receives this accept it?
A code someone will scan at a till or on a pallet — the barcode generator. EAN-13, UPC, Code128 and the rest, with the check digit computed for you.
A code someone will scan with a phone — the QR code generator. Seventeen payload types, logos, gradients, and every code scan-tested before you download it.
An identifier for a database row or an API object — the UUID generator, versions 1 and 3 through 7.
A colour value in a specific notation — the colour picker: HEX, RGB, HSL, OKLCH, CMYK, plus the nearest Tailwind token.
A number, or a list of them — random numbers in a range you set, or primes in one.
Barcode or QR code?
The single question people arrive with, and neither product page can answer it because each only knows about itself.
Barcode if the number already exists and something in a retail or logistics chain has to read it — a till, a warehouse scanner, an inventory system. A one-dimensional barcode stores a short number and nothing else. Its virtue is that a decades-old laser scanner reads it instantly and reliably, and that whole industries are built on the assumption that it will.
QR code if a phone is the reader and the payload is anything richer than a number: a URL, Wi-Fi credentials, a vCard, a payment string. QR holds far more data, survives partial damage thanks to error correction, and scans from any angle. What it does not do is participate in retail systems that expect a GTIN.
If the answer is “I want people to scan this poster with their phone”, it is a QR code. If the answer is “our supplier asked for a barcode on the box”, it is a barcode, and the number has to come from them.
Generated is not the same as registered
The distinction that causes the most disappointment, so it is worth being blunt.
A barcode you generate here is not an official product number. The generator draws a valid, scannable symbol with a correct check digit for whatever digits you type. It cannot allocate you a GTIN — those come from GS1, they cost money, and a retailer scanning a self-invented number will find it belongs to somebody else or to nobody. Fine for internal stock labels, not fine for anything going through a shop.
A UUID is unique, not secret. Collision is not a practical concern, but a v4 UUID in a URL is still a value someone can share, log or paste into a support ticket. Uniqueness is not authorisation. If a resource needs protecting, it needs an access check, not an unguessable name.
A QR code is only as good as what it points at. The code is permanent once printed; the URL behind it is not. Point printed codes at a link you control and can redirect, never at a campaign URL you will retire in six months.
Every tool on this page runs entirely in the browser, so nothing you encode — a payment string, Wi-Fi password or customer identifier — is transmitted anywhere.