QR Code Scanner
Scan QR codes directly from your camera or upload an image file.
Camera is offline
About QR Code Scanner
The QR Code Scanner is an in-browser utility that detects, binarizes, and decodes Quick Response (QR) matrix barcodes directly on your local device. Operating without backend server round-trips, the scanner provides two distinct ingestion modes: live real-time webcam/mobile camera stream analysis via HTML5 MediaDevices and Canvas 2D image extraction, or drag-and-drop static image file parsing (supporting PNG, JPEG, WebP, SVG, and screenshot snapshots). Using client-side image processing algorithms, it locates the three distinctive finder patterns (concentric square position detection patterns at the corners), calculates module perspective alignment and timing grids, corrects for lens rotation and skew, and executes Reed-Solomon error correction to extract raw alphanumeric or binary payloads. Because decoding happens strictly in browser memory, you can safely inspect unknown QR codes, verify authentication tokens, read Wi-Fi network credentials, or extract encoded URLs without triggering automated URL resolution or exposing your camera feed to remote infrastructure.
Common Practical Use Cases
Safely inspecting unfamiliar QR codes from printed flyers or emails without immediate URL redirects
Decoding two-factor authentication (2FA) setup keys from desktop screenshots into backup secret codes
Reading Wi-Fi configuration barcodes (WIFI:S:NetworkName;T:WPA;P:Password;;) on desktop workstations
Verifying ticketing and boarding pass barcode data integrity prior to event travel
How to Use QR Code Scanner
- 1Choose "Camera" to scan live or "Upload Image" to select a file.
- 2If using camera, allow permission and point at the QR code.
- 3The decoded text or URL appears instantly in the result card.
Practical Worked Examples
Scanning a Screenshot QR Code
Ticket_Screenshot.png (contains boarding pass QR)
https://example.com/tickets/verify?id=987654
Explanation: Extracts encoded URL payload from image.
Supported Formats & Specifications
Accepted Inputs:
- Webcam video streams
- PNG, JPG, WebP image files containing QR codes
Generated Outputs:
- Decoded text string or URL link
Key Features & Technical Capabilities
- Real-time webcam video stream decoding via requestAnimationFrame and Canvas 2D
- High-resolution image file drag-and-drop parsing (PNG, JPG, WebP, screenshots)
- Client-side Reed-Solomon error correction and perspective de-skewing
- Safe text and URL inspection before navigating or triggering network requests
- Zero video frame or image telemetry sent to external servers
Under the Hood: Browser Processing Architecture
- Uses jsQR binary raster scanner running inside client Web Workers / Canvas context
- Binarizes grayscale image data using adaptive thresholding (Bresenham/Otsu windowing)
- De-masks 8 standardized QR mask patterns according to ISO/IEC 18004 specifications
- Camera media streams are requested with facingMode: environment on mobile devices
Browser Limits & Edge Cases
- Requires clear lighting and unobstructed finder patterns (the three corner squares).
Common Mistakes to Avoid
- Covering one of the three corner finder patterns.
Local QR Matrix Generation & Privacy
Vector Synthesis EngineThe QR Code Scanner computes 2D Reed-Solomon error correction matrices and synthesizes vector QR barcodes completely inside your browser without intermediate tracking URLs or third-party redirection servers. Standard static web assets and client runtime scripts are delivered securely via CDN over encrypted TLS (HTTPS).
Frequently Asked Questions
Are my camera stream or uploaded images transmitted to any server?
No. Video frames and uploaded images are processed entirely in your web browser memory buffers and discarded immediately. No frames are recorded, saved, or uploaded.
Why does the scanner fail to detect a QR code from a camera feed?
Common causes include insufficient ambient lighting, heavy lens glare or reflections on glossy surfaces, extreme tilt angles, or physical obstruction of any of the three corner finder squares.
Can this tool read inverted (white modules on black background) QR codes?
Standard QR codes feature dark modules on a light background. High-contrast inverted codes may require uploading the image file where our preprocessing inversion filter can normalize contrast.
Is it safe to scan untrusted QR codes with this tool?
Yes. Unlike native mobile camera apps that immediately open decoded URLs in a browser window, this tool displays the decoded text payload as plain text first. This allows you to verify the exact destination URL and query parameters before clicking.