preview_qr_encoding

uk.qart/qart · Verify this server

Work out how a payload will encode as a QR code, without creating anything. Returns the exact string the pixels would carry, its byte length, the QR version and module count required, the capacity remaining at that version, and any warnings. Costs nothing and mints nothing. Use this to answer questions like "will this URL fit at error correction level H" or "how much does a long Wi-Fi password cost me in QR density". Higher ECC survives damage better but needs more modules for the same data; more modules print smaller and get harder to scan. payloadKind 'qart_code' sizes the RETARGETABLE variant instead: the pixels carry a 16-byte qart.uk/_ link rather than your data, which is usually several versions smaller. Compare the two before committing to a print. This returns metadata only, never the module grid. For the actual black/white matrix, call get_qr_matrix.