QR Codes Explained: How They Work and How to Stay Safe

The QR code — short for Quick Response — packs text, URLs, contact details, WiFi credentials or payment information into a black-and-white square a phone camera decodes in milliseconds. Originally an automotive-industry tracking tool, it is now how restaurants seat you, how museums guide you, and how half the world's posters link to the web. This guide explains what the squares contain and the two sides of QR security.

What a QR code stores

A QR code is a two-dimensional barcode: modules (the black squares) arranged in a grid, with position markers in three corners that let a camera orient the code. The content is ordinary data — most often a URL, but also plain text, Wi-Fi credentials (host, SSID, password), vCard contact details, or payment strings. The scanner reads the modules and hands the result to the right app.

What makes a code scannable

• Contrast: dark modules on a light background — the scanner needs the pattern to stand out.
• Quiet zone: keep clear padding around the code; a busy design bleeding to the edge breaks scanning.
• Size: the printed code must stay large enough for a camera at normal distance.
• Error correction: a decent level (15–25%) lets the code survive small damage, logos or dirt.
• Testing: always scan your own output on a phone before printing or publishing.

The security side: QR phishing

Anyone can encode anything. A QR code pasted on a poster, email or payment terminal can point to a fake login page, a malware download, or a fraudulent payment prompt — a trend known as quishing (QR-phishing). A scanner may not notice that the 'menu' they opened is a spoofed site.

• Before scanning, glance at the URL your camera preview reveals and compare it to the expected domain.
• Prefer scanning official, printed codes over sticker-covered or hand-corrected ones.
• Never enter passwords, card numbers or OTPs on a page you reached through an unfamiliar QR code.
• On the generator side, always make the final URL explicit and keep redirects to a minimum.

Generating QR codes in Convrs

Convrs includes a QR code generator that runs entirely in the browser. Enter the text or URL, pick size and error-correction level, optionally inject a logo in the safe center area, and export a crisp PNG or SVG. Because generation is local, the content you encode — a private link, an internal tool tip, a business card — never touches a server.