What is a QR code?
A QR code (Quick Response code) is a two-dimensional barcode that smartphones and tablet cameras can scan to instantly open a URL, connect to WiFi, save a contact, or compose an email or message. Originally developed by Denso Wave in Japan in 1994 for tracking automotive parts, QR codes have become ubiquitous in marketing, restaurants, events, and everyday life.
QR code types supported
The ToolHive QR generator supports six types of QR codes. URL QR codes are the most common — they encode a web address that opens in the phone's browser when scanned. Plain text QR codes store any text up to the capacity of the code. WiFi QR codes store network credentials so guests can connect with one scan, no password typing required.
Email QR codes pre-fill the recipient address and subject line, making it easy to add a QR code to business cards or flyers that opens a pre-addressed email. SMS QR codes pre-fill a phone number and optional message body. vCard QR codes encode a full contact record that can be saved directly to the phone's address book.
Understanding error correction levels
QR codes have built-in error correction that lets them remain scannable even when partially damaged, dirty, or obscured. There are four levels: Low (L) corrects up to 7% damage — smallest code, fastest scan. Medium (M) corrects up to 15% — a good balance for print use. Quartile (Q) corrects up to 25% — recommended if you plan to add a logo. High (H) corrects up to 30% — best for outdoor use or when the code may be worn.
Medium is the default and suitable for most use cases. Use High if you are printing on packaging that may be scratched, or if you plan to overlay a company logo in the centre of the code.
Choosing the right size
For digital use — websites, social media, email — a 300px QR code is fine. For print, the minimum recommended physical size is 2cm × 2cm for codes scanned at arm's length, and 10cm × 10cm for codes on posters or signage viewed from a few metres away. Download the PNG and scale it in your design software.
Colour customisation
The foreground and background colour pickers let you match QR codes to your brand. The most important rule: maintain sufficient contrast between the foreground (module) colour and the background. Dark on light always works; light on dark usually works. Avoid colours that are too similar — a dark red on black will fail to scan reliably.
White is the safest background colour. If you need a coloured background, ensure the foreground modules are at least 4:1 contrast ratio against it.
WiFi QR codes — a particularly useful type
WiFi QR codes are underused and extremely practical. Instead of reading out a long WiFi password to every guest, print a WiFi QR code and stick it on your router, at your reception desk, or on your menu. Guests scan it and their phone connects automatically — no typing, no misheard characters.
The format is WIFI:T:WPA;S:NetworkName;P:password;; — the generator builds this automatically from the fields you fill in.
Privacy note
All QR codes are generated in your browser. Passwords, URLs, and personal contact details you enter in the form are never transmitted to any server.