QR Code Reader

What is a QR code reader?

A QR code reader decodes the patterns printed on a QR square and turns them into readable content. Depending on the code, that content can be a website address, plain text, Wi-Fi settings, contact details or a payment reference.

How does reading an image work?

• The image is rendered on a hidden canvas in your browser.
• jsQR inspects the position markers and the black-and-white matrix.
• The captured data is decoded from the pattern.
• The result is shown as text you can copy.

When do you need to read a QR code from an image?

• Recovering a link from an old screenshot.
• Opening a printed code that you cannot scan live.
• Verifying what a code contains before trusting it.
• Forwarding the raw value of a code to someone else.

Why does browser-only decoding matter?

The image is processed with JavaScript on your device and never uploaded. Codes sometimes contain payment or login data, so keeping the process local protects you even when the payload itself is sensitive.

Tips for a successful read

Crop closely around the QR square, keep the image sharp and make sure the code is flat in the frame. A little blur or a steep angle is the most common reason a read fails; when it does, nothing is sent anywhere, so you can simply try a better picture.