QR Code FAQ

A QR code (Quick Response Code) is a 2D barcode invented by Masahiro Hara at Japan's Denso Wave in 1994, originally for tracking automotive parts.

Compared to 1D barcodes, QR codes store info in both horizontal and vertical directions—larger capacity, faster recognition. A standard QR code holds up to 7089 digits, 4296 alphanumeric, or 2953 bytes (including Chinese). Scan with a phone camera to read—widely used for URL sharing, mobile payments, electronic business cards, WiFi sharing.

QRCode.wang uploads nothing. This is a static website; all generation and scanning run locally in your browser JavaScript. The server only hosts web files—receives and stores no user input or uploaded images.

No cookie tracking, no third-party analytics (no Google Analytics, Baidu stats, etc.), all JS libraries and fonts are local—no third-party CDN requests. Suitable for generating QR codes with WiFi passwords, personal contacts, and other sensitive info. Deploy over HTTPS for transport security.

Completely free. No registration, no paywall, no usage limits, no ads. All features—7 type generation, Logo embedding, PNG/SVG/JPG downloads, camera scanning—are free. Generated QR codes contain no watermark.

Visit QRCode.wang home:

1. Select the "Generate QR Code" tab
2. Click a type button (Text/URL, WiFi, vCard, etc.)
3. Enter content in the form; preview updates in real time
4. Optional: customize colors, size, error correction, upload Logo
5. Click PNG / SVG / JPG to download

No registration needed; data processed locally. See the complete tutorial.

Check in order:

1. Content too long—dense modules hard to scan. Shorten content or use a URL shortener (bit.ly).

2. Size too small—export at least 256x256 pixels. Print rule: scan distance / 10.

3. Insufficient contrast—ensure dark foreground with light background. Avoid light foreground, dark background, or similar colors.

4. Logo too large—with Logo use Q or H error correction; Logo under 22% of QR area.

5. Blurry print—export SVG vector for print to avoid scaling blur.

Error correction is the QR code's ability to remain readable when occluded or damaged:

Higher correction = denser modules for same content. QRCode.wang auto-switches to H when uploading a Logo.

Yes. In QRCode.wang's "Appearance" section, upload a Logo image (recommend square transparent PNG, under 2MB). The system:

· Auto-embeds at QR code center
· Adds a white border for contrast
· Auto-switches to H error correction for readability

Logo size about 22% of QR area—too large blocks modules and prevents scanning.

Black-and-white QR codes have the highest contrast and best scan rate—the default. QRCode.wang supports custom foreground and background colors for colored QR codes.

Notes: Foreground and background must have sufficient contrast. Recommend dark foreground with light background (e.g. dark blue + cream, black + light yellow). Avoid light foreground, dark background, or similar colors (e.g. red + green).

In QRCode.wang select "WiFi" type, fill in:

· Network Name (SSID): WiFi name, case-sensitive
· Password: WiFi password
· Encryption: usually WPA/WPA2 (most common)
· Hidden network: enable if router hides SSID

Others scan to connect WiFi without password entry. iOS 11+ and most Android natively support. See WiFi QR page.

In QRCode.wang select "vCard" type, fill in name, phone, email, organization, title, website. After generation, others scan to save contact to phonebook in one click.

Uses vCard 3.0 standard, iOS/Android compatible. See vCard QR page.

In QRCode.wang select "Text/URL" type, paste the URL (e.g. https://qrcode.wang) in the input, QR code generates instantly.

Use the full URL with https:// for correct redirection. Download PNG to put on posters, cards, or web pages.

Depends on content type—these are standard behaviors natively supported by phone systems, no extra app needed:

· URL: opens in browser
· tel:: opens dialer
· SMSTO:: opens SMS app with pre-filled content
· mailto:: opens mail composer
· WiFi: shows connect prompt
· vCard: shows save-contact form

Visit QRCode.wang, switch to "Scan" tab. Four methods:

1. Drag-drop: drag image to drop zone
2. File select: click to choose local image
3. Ctrl+V paste: paste screenshot or clipboard image
4. Camera scan: real-time recognition, front/back switch

After recognition, auto-detects content type (URL, WiFi, vCard, etc.) and provides action buttons. All decoding is local—images not uploaded.

Upload the WiFi QR code image via QRCode.wang's scan function, or scan with camera. The system auto-parses:

· Network Name (SSID)
· Encryption (WPA/WEP/no password)
· Password

Provides a "Copy password" button. Format: WIFI:T:WPA;S:NetworkName;P:password;;

Camera scanning needs:

1. Device with camera (phone or computer)
2. Browser camera permission granted (first-time prompt)
3. HTTPS environment or localhost (browser security restriction)
4. Camera not occupied by another app (Zoom, video calls)

QRCode.wang supports front/back camera switching—point at QR code to auto-recognize; vibration feedback on success.

General: PNG; print or scale: SVG; size-sensitive: JPG.

Capacity depends on content type and error correction:

· Digits only: up to 7089
· Alphanumeric: up to 4296
· Bytes (UTF-8, incl. Chinese): up to 2953
· Chinese characters: up to 1817

Higher error correction = lower capacity. For long URLs, use a shortener to avoid dense modules.

Yes. QR codes support UTF-8 encoding and can store Chinese, English, numbers, symbols, emoji. Chinese takes more bytes (3 per character), so Chinese content reaches capacity limits faster than pure English at the same error correction. For long Chinese text, use a short link or shorten content.

Print size depends on scan distance. Rule: QR side length ≈ scan distance / 10.

Export SVG vector for print; resolution at least 300 DPI.

Static QR codes: content encoded directly in the image, cannot be modified after generation, fastest scan, no usage fee. QRCode.wang generates only static QR codes.

Dynamic QR codes: point to a modifiable redirect link, content can be updated, scan stats available, but require paid services and expire when service stops.

Static QR codes suffice for daily use; consider dynamic only when you need to modify content later or track scan stats.

Static QR codes themselves don't expire. QRCode.wang generates static QR codes—content is encoded directly in the image, scannable as long as the image exists.

Note: if the QR's target URL becomes invalid (short link expires, page deleted, domain expired), scanning won't open it. This is a target URL issue, not a QR code issue.

Dynamic QR codes (pointing to modifiable redirects) usually require paid services and expire when the service stops.

The QR code standard itself is open—ISO/IEC 18004 international standard, no copyright restrictions. QR codes generated with QRCode.wang can be freely used commercially, including:

· Product packaging & labels
· Advertising materials
· Business cards & brochures
· Website & app embeds
· Event sign-in & coupons

QRCode.wang-generated codes contain no watermark or copyright notice.