Free tool
QR code debugger
Upload a QR code image — or snap one with your phone camera — to decode its contents and inspect every detail. Images are processed locally and never leave your device.
100% client-side — your image is decoded in your browser and never uploaded anywhere.
Need tracked QR codes? Create a free account to generate branded QR codes with built-in scan analytics.
Drop a QR image here
or click to upload · paste from clipboard · snap with camera
Decoding...
Upload a QR code image above to see what's inside it
Decoded content
QR metadata
Encoding segments
Each segment encodes part of the data in a specific QR encoding mode.
Detected finder pattern corners
Frequently asked questions
A QR code debugger is a tool that decodes a QR image and shows you everything inside it: the encoded text, the encoding modes used for each segment, the QR version (size), the raw bytes, and the detected finder-pattern corners. It's useful when a QR isn't scanning on some devices, or when you want to double-check exactly what was encoded before you print or share it.
Your image is drawn onto an HTML canvas inside your browser, and the pixel data is passed to the open-source jsQR library, which locates the QR's finder patterns, reads the module grid, and decodes each data segment. Everything happens locally — the image never leaves your device and is never uploaded to any server.
No. This tool is fully client-side. Your QR image is processed entirely in your browser memory — there is no upload, no server call, no tracking of the image itself, and nothing is stored.
The most common causes are: low contrast between the code and its background, blurry or out-of-focus photos, missing quiet zone (the white margin around the QR), a logo that's too large and overlaps the data modules, excessive rotation, or damage to the finder patterns (the three corner squares). Try cropping tight around the code, improving lighting, and making sure the three corner squares are clearly visible.