QR for links, UPI, WiFi & text — 100% free, runs in your browser
QR codes have become the fastest way to hand someone a link, a payment request or a WiFi password without typing. This makes codes for all of those. UPI codes in particular are worth generating properly — the format matters, and a malformed one simply will not open a payment app.
Yes. The upi:// format is the standard that GPay, PhonePe, Paytm and bank apps all read.
800 pixels or larger. Small codes fail when printed, especially on rough paper or if the print is faded.
No. A QR code is just an encoded string, so it works for as long as whatever it points to still exists.
Not here. Codes carry error correction so a small centre logo usually still scans, but you would need a design tool to add one.