How QR codes work
What is really in the pattern, how much of it can be damaged before a scan fails, and what a camera is doing when it finds one. Useful before you decide how small to print.
QR Code Basics
What is a QR code?
A QR (Quick Response) code is a two-dimensional barcode that stores information — most often a link — as a grid of dark and light squares. A phone camera reads the grid and decodes the content in under a second. Unlike traditional barcodes, QR codes hold far more data, can be scanned from any angle, and include built-in error correction so they still work when partially obscured.
How does a QR code work?
The content you enter is encoded into a pattern of modules (the small squares), together with error-correction data. The three large corner squares tell a scanner where the code is and how it is oriented. When someone points a camera at it, the scanner locates those markers, reads the module grid, corrects any damaged areas, and decodes the original content — a URL opens in the browser, contact details offer to save, Wi-Fi credentials offer to connect.
How do I create a QR code?
Open the QR Code Generator, pick a content type, enter your content, and the preview updates instantly. From there you can customize colors, dots, eyes, logo and frame, then press Download and choose a format and size. No account is needed and the code is yours to use anywhere.
What information can I put inside a QR code?
ScanMe Online supports 28 content types: website URLs, plain text, Wi-Fi credentials, contact cards (vCard), phone numbers, email, SMS, WhatsApp, restaurant menus, payments, reviews, coupons, tickets, app downloads, PDFs, social media profiles, FaceTime, Zoom, locations, events, calendars, music, crypto addresses, pet ID tags, lost-and-found labels, vehicle info, insurance details and pharmacy info. Each type has its own form that produces correctly formatted content.
Can I create a QR code for Wi-Fi?
Yes. Choose the Wi-Fi type, enter your network name, password and security type (WPA/WPA2, WEP or open), and the generated code lets guests join your network by scanning, with no typing. iPhones (iOS 11+) and Android phones (10+) connect straight from the camera app. Anyone who can scan the code can join the network, so for a business, put guests on a separate guest network.
Can I create a contact (vCard) QR code?
Yes. The Contact type builds a standard vCard containing your name, phone, email, company and more. Scanning it opens the add-contact screen on both iPhone and Android with every field already filled in, so nobody mistypes your details. Because the details are encoded in the printed code itself, update the code if your details change, or use a dynamic QR code pointing to a page you keep current.
Can I generate multiple QR codes?
Yes, one at a time, with no limit on how many you create. Each generated code is saved to your in-browser history (up to 100 recent items) so you can re-download it later on the same device. There is currently no bulk or CSV batch generation; each code is created individually in the editor.
Can I reuse a QR code?
Yes. A downloaded QR code is a normal image file: you can print it, embed it and reuse it as many times as you like, in as many places as you like. Every copy of the same code carries the same content. Scanning is unlimited and free regardless of how many people scan it.
Can the same QR code be scanned by both Android and iPhone?
Yes. QR codes are an international standard (ISO/IEC 18004), and codes made with ScanMe Online are fully standard. Any modern iPhone or Android phone reads them directly from the built-in camera app, and dedicated scanner apps read them too. If a customized code scans poorly on one platform, that is a contrast or size issue rather than a compatibility issue, and the scan reliability score in the editor helps you catch this.