What each content type encodes
A QR code stores a string of text. The scanning app decides what to do with it. A URL is stored exactly as typed, so include the https:// prefix or the camera may treat it as plain text. Phone produces tel:+441234567890 and SMS produces SMSTO:number:message, both of which phones recognise and offer to dial or send.
Email builds a mailto: link with the subject and message appended as query parameters, so a scan opens a pre-filled draft. Contact writes a vCard 3.0 block with FN, N, ORG, TEL and EMAIL lines that iPhones and Android phones import straight into the address book. Text stores whatever you type, which is handy for serial numbers and asset tags.
How the Wi-Fi payload is built and escaped
The Wi-Fi type writes the line that phone cameras understand: WIFI:T:WPA;S:network name;P:password;; plus H:true; when the hidden box is ticked. T is the security type. The tool offers WPA, which covers WPA2 and WPA3, WEP for old equipment, and nopass for an open network, in which case the P field is left out.
Five characters have meaning inside that format: backslash, semicolon, comma, colon and double quote. If your SSID or password contains one, the tool prefixes it with a backslash so scanners read it literally; p;ss:word is written as p\;ss\:word. Hand-typed Wi-Fi codes usually fail on exactly this point. Our Wi-Fi QR code scanner shows the decoded fields so you can confirm them.
Choosing error correction, size and colours
QR codes carry Reed-Solomon error correction, and the level decides how much of the pattern can be lost before a scan fails. The price is capacity: at level H a code holds less than half what it holds at L, so a long vCard at H becomes a dense block of tiny modules. If the tool reports too much data, shorten the content or lower the level.
The PNG size only sets the pixel dimensions of the raster file. The SVG has no fixed size. For print, keep the code at least a tenth of the scanning distance, and leave extra white space around it when the background is busy (the generator adds a two-module quiet zone of its own). Dark modules on a light background scan most reliably. Inverted designs fail in some camera apps.
Testing before you print a run
Scan the downloaded PNG with two different phones, from the distance and angle people will really use. Check that the URL opens the right page, that the Wi-Fi code offers the right network, and that the contact card lands in the address book with the fields in the right places.
Then print one copy at final size on the final material and scan that. Glossy laminate causes glare, curved surfaces distort the grid, and a code shrunk onto a small label can drop below what a camera resolves. Upload a photo of the print to the QR code scanner to see the raw payload and catch a stray space or a missing scheme.
What this generator does not do
It makes static codes only. There is no way to change the destination after printing, no scan counter and no short link, because those need every scan to pass through a server that can disappear or start tracking people. If you want editable codes, you need a redirect service, and you should read its terms before committing a print run to it.
There is no logo overlay or styled module shape either. Both eat into the error correction margin, and a code that scans on the designer's phone but not on a customer's older one is the usual result. Capacity is finite too: a QR code tops out at 2,953 bytes, and anything past a few hundred characters is impractical to scan from print.