QR Code Reader

QR codes solved one problem perfectly: getting a URL from physical space into a phone without typing. A printed code on a poster, a screen in a store, a business card — point your camera, get the link. Every iPhone and Android phone has this built into the camera app, which is the right place for it. So why a QR reader on a website?

Because sometimes you have a QR code in a place that isn't your phone's camera. A screenshot someone sent you. A QR code embedded in a PDF or in an email. A photo of a code your phone's native scanner couldn't read because the lighting was bad. Or you're on a desktop without an easy way to point a phone at the screen and you just want to know what the code says without typing the URL manually. That's the niche this tool covers.

The implementation uses **jsQR**, a JavaScript QR decoder that runs entirely in your browser. It's small (about 50 KB minified) and fast. For live scanning, the tool grabs your camera stream via `getUserMedia`, draws each frame to a canvas, extracts the raw pixel data, and feeds it to jsQR. When a code is detected, the camera stops automatically and the decoded payload appears. For image scanning, the same pipeline runs on a single still image you upload.

A QR code's payload can be:

- **A plain URL** (`https://example.com/path`). The most common case. The tool detects the URL scheme and offers an 'Open in new tab' link. - **A short text** (anything that doesn't start with a URL scheme). Displayed verbatim, copyable with one click. - **A structured payload** that follows one of the QR conventions: Wi-Fi credentials (`WIFI:T:WPA;S:network;P:password;;`), vCard contacts (`BEGIN:VCARD...END:VCARD`), calendar events (`BEGIN:VEVENT...`), email composition (`mailto:address?subject=&body=`), SMS composition (`sms:number?body=text`), telephone dialing (`tel:+1234567890`), geolocation (`geo:37.78,-122.40`), cryptocurrency payments (`bitcoin:address?amount=0.01`). The tool shows the raw payload — your phone or OS knows how to handle each format if you copy and paste it into the right app.

A few practical notes.

**Live scanning is faster than image upload for most cases.** The frame-by-frame approach finds codes quickly under good lighting (typically under a second from camera-start to decoded). Image upload is slower per-attempt because you have to take the photo, switch to the browser, drop the file. But upload is more reliable for tricky codes — bad lighting, low resolution, weird angles — because you can pick the best frame yourself.

**The 'environment' camera is requested.** On phones this is the back camera, which is what you usually want — it's higher quality and points away from you. On laptops there's only one camera typically, so this hint is ignored. If you specifically want the front camera (selfie camera) on a phone, the OS's native QR scanner is the better tool — this page doesn't expose a camera-switch UI to keep the surface minimal.

**Camera permission is one-time per origin.** Modern browsers remember the permission grant for justfiletools.com (or your domain). The next visit doesn't prompt again. You can revoke the permission in your browser's site settings if you want.

**Privacy is core.** This is the whole reason the tool exists in this browser-only form. Online QR scanners that upload your image to a server have a clear failure mode: your QR code could contain a Wi-Fi password, a session token, a private payment request, a private vCard — none of which you want sitting in someone else's logs. This tool's jsQR runs in your browser, full stop. The camera stream is a local HTMLMediaStream; the image you upload is a local Blob; the decoding is a JS function in this page's bundle. Verify in DevTools — the network panel stays empty during operation. The camera light turns off as soon as you stop the scan or a code is found.

**Edge cases handled correctly.**

- **No camera available**: the tool detects `NotFoundError` and tells the user to use the Image Upload tab instead. - **Permission denied**: the tool detects `NotAllowedError` and points to the Image Upload fallback with a clear message about how to grant permission later. - **Code not found in image**: the tool says so explicitly and suggests retrying with a higher-resolution or less-skewed image. It doesn't silently fail. - **Page unmount / mode switch**: the camera stream is stopped and the animation-frame loop is cancelled, so no memory leaks and no zombie camera light after navigation.

**What this tool deliberately doesn't do**:

- **Decode non-QR barcodes** (Code 128, EAN, UPC, ITF, etc.). For those, a different library is needed; jsQR is QR-only. If users want general barcode reading, a separate tool is the right answer — bundling ZXing into the QR reader would be wasteful for the typical user. - **Generate QR codes**. The existing QR Code Generator tool on this site covers that direction. - **Continuously scan after finding one code.** The first code stops the camera. If you want to scan a sequence, click Start again. This is intentional — most users are scanning one thing and want a clear 'done' state.

In a world where every phone has a built-in QR scanner, the niche use cases — screenshots, embedded codes, no-phone scenarios — are the reason this exists. It's small, it's fast, it stays in your tab.