Shops & street vendors
A UPI payment QR with the shop name, a fixed amount and a note, ready for the counter, the stall or an invoice.
UPICase study · Web app
QR Studio
A free, private QR code generator for small businesses: links, Wi-Fi, UPI payments and contact cards in your own colours and logo, ready to print. It runs entirely in the browser, with no sign-up and no uploads.
Type
Web app · free tool
My role
Product, design and development
Built with
HTML, CSS, vanilla JavaScript
Status
Live
6QR types: link, text, Wi-Fi, UPI, contact card, email/SMS
0sign-ups, uploads or watermarks
PNG + SVGPrint-ready downloads, up to 1600 px or vector
1 filePlain HTML, CSS and JavaScript. No libraries, works offline
Live demo
Try it right here.
QR Studio works great on phones. Open it full screen to create, customise and download your code.
Open QR Studio ↗Scan to open on your phone
Made with QR Studio itself.
Try this: pick the Wi-Fi tab, type a network name and password, add a logo and download the SVG. Nothing you type leaves your browser.
Use cases
Made for the places people actually scan.
Cafés, hotels & offices
Guests scan once to join the Wi-Fi, with no spelling out passwords. Hidden networks are supported too.
Wi-FiRestaurants & cloud kitchens
A table-top QR that opens the online menu, ordering page or Google review link.
LinkBusiness cards & events
One scan saves name, phone, email, company and website straight to the contacts app.
vCardFlyers, posters & packaging
Brand colours and a centre logo, exported as SVG so the code stays sharp at any print size.
Link + SVGBookings & feedback
A pre-filled email or SMS so customers can book, ask a question or leave feedback in one tap.
Email / SMSWhat it does
- Six code types for links, plain text, Wi-Fi, UPI payments, contact cards and email/SMS.
- Your brand: pick dot and background colours and drop your logo in the centre.
- Print-ready output: PNG from 200 to 1600 px, a vector SVG, or copy straight to the clipboard.
- Error correction from Low to High; adding a logo switches to High automatically so the code still scans.
- Live preview that updates as you type, with the QR version, size and capacity shown.
- Contrast check that warns when colours could make a code hard to scan.
Private and secure by design
- Runs entirely in your browser. No account, no server and no tracking. It even works offline.
- Locked down: a strict Content Security Policy blocks every network request, and the app’s script is pinned by its SHA-256 hash.
- Safe logos: uploads are checked for type and size, then redrawn on a canvas before use.
- Safe links: only http and https are allowed, and links with embedded passwords are blocked.
- Validated input: UPI IDs, amounts, Wi-Fi keys, phone numbers and emails are checked and correctly escaped.
The brief
A fast, free QR code generator that small businesses can use without an account: website links, Wi-Fi, UPI payments and contact cards, in their own colours and with their logo, ready to print.
The challenge
Many free QR generators ask you to sign up, add watermarks or send your data to a server, yet Wi-Fi passwords and payment details are exactly the kind of data that should stay private. The tool had to keep everything on the device and still produce print-quality codes that scan reliably.
How I built it
The QR encoder is written from scratch in plain JavaScript, following the QR code standard (ISO/IEC 18004): versions 1 to 40, four error-correction levels, Reed–Solomon error correction and automatic mask selection. There are no libraries and no build step. The whole app is a single HTML file that works offline. Every input is validated and escaped for its format, and a strict Content Security Policy keeps the page from making any network request.
Built with
HTML, CSS, vanilla JavaScript, Canvas API, SVG export, Content Security Policy
Outcome
QR Studio is live and free to use on this site. Test codes for links, UPI payments and Wi-Fi, including one with a centre logo, decode correctly with a standard QR reader.
Next project
Need a custom tool like this?
Calculators, generators, booking helpers or small AI tools for your website. Tell me what you need and I usually reply within one business day.