Carry text across the air gap.

Print a numbered set or play it on screen. Scan in any order to restore the exact text.

01 / Encode

Text to transfer

0 bytes

Label Optional · up to 80 UTF-8 bytes

Chunk size UTF-8 bytes per data frame. Smaller chunks produce more, less dense codes. Error correction Approximate recoverable codeword damage, not a guarantee for a damaged area. Q is the paper default. Frame interval Milliseconds per frame; 250 = 4 fps. Increase if the reader misses frames. Screen code size Target pixels, including the quiet zone. Rounded to whole modules; limited by your screen. Print code size Millimetres including the quiet zone. A4 defaults to two columns, three rows.

No set generated yet.

02 / Restore

Point the camera at one code inside the square. Start anywhere in the sequence. Frame 0 identifies the label and byte length.

Expected payload id Optional · 16 lowercase hex characters

Camera access needs browser permission and usually localhost or HTTPS. With a local file, try the camera or use a cropped QR photo below.

Read QR photos One complete code per photo, including its white margin. Processed locally.

Paste decoded frame text

Waiting for the first frame.

Verified text Only shown after every frame and SHA-256 verification

Format, print guidance & privacy

KBQR1 is a plain indexed format, not UR. Every frame includes the set id, frame number, count and whole-payload SHA-256. All frames including index 0 are required. A missing sheet cannot be reconstructed from other sheets; QR error correction only protects each individual code.

Default: 160-byte chunks, Q correction, 65 mm codes with a four-module white margin. Print at 100% on A4 with browser headers and footers off. Use black on white, ordinary quality or better, and test a complete restore on your actual inkjet before relying on the paper.

QR has mature browser encoders and jsQR camera decoding. Aztec and Data Matrix need different readers; qr-adapter.js is the explicit extension point. Neither is implemented here.

No uploads, analytics, external fonts, storage or network calls. The content security policy blocks connections. QR encoding is not encryption; printed codes and saved exports contain your input. The checksum detects corruption; it does not authenticate the sender. Validate KPOP backup content in KPOP after restoring it.

See README.md, FORMAT.md, PRIOR-ART.md and AGENT-HANDOVER.md in this folder.