Reads QR codes with an in-house ISO/IEC 18004 decoder — no camera, no upload: the image is binarised adaptively, the three finder patterns and the alignment pattern are located, the module grid is sampled through a perspective transform, format and version information are BCH-corrected, the data is unmasked, de-interleaved and repaired with Reed–Solomon error correction, and every mode (numeric, alphanumeric, byte with ECI charsets, Kanji, FNC1, structured append) is parsed. Rotated, mirrored and inverted codes are handled. The content is interpreted (URL, Wi-Fi, vCard/MECARD, email, phone, SMS, location, authenticator secret, calendar) and the report shows version, error-correction level, mask, blocks and how many codewords were corrected. Everything runs locally.