Read QR / barcode
Decode any QR code or barcode from an image, on your device.
Runs on your device. The file is never uploaded.
Read QR / barcode scans an image file and prints one line for every code found, naming the symbology it matched before the string it decoded. The formats list is passed empty, so the reader tries every symbology it knows. Candidates it marks invalid are dropped, and an image with none left stops with no barcode found.
Questions
Which barcode types can it read?
Every symbology the bundled zxing-wasm reader supports, because the tool passes an empty format list, which means try them all. That covers the 2D codes, QR including Micro and rMQR, Data Matrix, Aztec, PDF417 and MaxiCode, and the linear ones, EAN and UPC, Code 39, Code 93, Code 128, Codabar, ITF, DataBar, Telepen and DX Film Edge. You do not have to say which one you have.
What does the result look like?
One line per barcode found, giving the symbology name, a colon, then the decoded text. An image containing several codes gives you several lines, and each is decoded independently. Only results the reader marks as valid are reported, so a partial or misread candidate is discarded rather than shown as noise.
Why does it say no barcode found?
Because nothing valid decoded in that image, and the message is your file name followed by "no barcode found". The reader does not throw on a bad image, it comes back empty, so the tool raises this instead of returning silence. Blur, low contrast, a strong angle, glare and heavy cropping are the usual causes. A sharper, straighter, higher resolution photo usually fixes it.
Is my image uploaded to a decoding service?
No. The decoder is zxing-wasm running as WebAssembly inside a Web Worker in this tab, and the wasm file is served from this site rather than from a CDN. That last part is deliberate: the library defaults to fetching its wasm from a public CDN, which would tell a third party which tool you are using and would break offline use. That default is replaced here.
Can I read codes from a PDF or straight from my camera?
From an image file. Drop PNG or JPEG photos and screenshots; the tool is per-file, so a batch of images gives one result per image. There is no live camera mode. For a barcode inside a PDF, export or screenshot the page as an image first, then drop that.
How is this different from Generate QR / barcode?
It runs the other way. This one reads a code out of an image you already have. Generate QR / barcode takes text you type and writes a PNG of a barcode. They use the two halves of the same library, the reader and the writer, each with its own WebAssembly file.