What is a QR Code and How Does It Work?

What is a QR Code and How Does It Work?

A QR (Quick Response) code is a 2D matrix barcode that stores text, URLs, Wi-Fi credentials, IDs, or payment payloads.

Structure Overview

Finder patterns (3 squares), alignment patterns, timing patterns, version info, format info, data modules, and error correction blocks.

Encoding

Input data converted to mode (numeric, alphanumeric, byte, Kanji), segmented, Reed–Solomon error correction applied, matrix filled.

Decoding

Camera captures image; binarization; perspective correction; pattern detection; data extraction; error correction; output text or URL.

Error Correction Levels

L (7%), M (15%), Q (25%), H (≈30%). Higher allows logo overlay but reduces capacity.

Static vs Dynamic Basics

Static: direct data in symbol. Dynamic: short redirect URL pointing to editable destination.

Common Payloads

URL, vCard (qr code for business card), Wi-Fi credentials (qr code for wifi password), payment strings (qr code for payment), form links (qr code for google form).

Generate your first code using a free qr code generator and scan with any qr code scanner online.