EXPERIMENTAL COLOR 2D CODE

QuadQR

RGBW data cells at 2 bits per cell, with an optional experimental High Density Mode using Triangle16 split cells at 4 bits per body cell, with spectral interleaving, confidence-aware Reed-Solomon ECC, and camera color calibration.

QuadQRHigh Density experimentalformat v6

Generator

Create QuadQR code

Not generated

ADVANCED

Optional features
Open only what you need
Output & renderingImage size, quiet zone, style and print mode

Classic keeps every module fully solid. Styles only change rendering, never the encoded data.

Center logoAdd branding with automatic ECC-aware sizing
Logo image

Transparent logo pixels are preserved. Disable the logo to keep the selected file for later, or remove it completely with Remove logo.

CompressionReduce repetitive payloads automatically, without payload types

Auto performs one balanced pass with LZ level 6, DEFLATE level 6, and Brotli quality 6, then stores the smallest final representation. Smart is opt-in CPU-heavy mode: it starts the same way and only tries stronger DEFLATE/Brotli levels when they have a realistic chance of reducing the QuadQR version.

Digital signatureOptional offline Ed25519 integrity verification
EncryptionPassword or raw-key AES-256-GCM protection

Standard mode stores the payload normally. Security is opt-in and does not alter QuadQR scanning or Spectrum ECC.

Output

Code

SVG PREVIEW
Code detailsMatrix, capacity, ECC and output metadata
Matrix
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Output
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Payload
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Capacity
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Density
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ECC
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Alignment
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RS blocks
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Mask
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Utilization
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Features
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CRC-32
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ScanabilityAutomatic robustness score and distortion checks

SCANABILITY

Not testedAutomatically tested before export; re-run after experimenting if needed.

Image scanner

Scan an exported image or photograph

Secure scanning supported. Password and raw 256-bit-key QuadQR codes are detected automatically. The encrypted payload remains locked until the correct credential is entered in the scan result.

No image scanned yet.
Scanner debugFinder geometry, sampling, color confidence and ECC stages

QUADQR FORMAT

Four states, exactly two bits per data cell

Direct 2-bit mapping. Red = 00, green = 01, blue = 10, and white = 11. One byte occupies exactly four data cells.

High Density Mode. When enabled, the experimental Triangle16 layout splits each payload module on a fixed / diagonal. Each triangle uses multiple protected interior samples with instability-aware confidence, creating 16 states and 4 bits per body cell while keeping the protected header solid-color. It is disabled by default.

Spectrum ECC 2.0. GF(256) Reed-Solomon first tries normal correction, then confidence-guided erasures. If that still fails, a bounded soft-decision pass can try the scanner's second hypothesis for a few least-confident cells without adding ECC overhead.

Spectral-spatial interleaving. Logical codeword cells are scattered across distant physical modules with a reversible zero-overhead permutation, improving resistance to localized damage without reducing capacity.

Perspective geometry. Three large finder patterns stay fixed. Versions 2 through 40 use distributed 5×5 nested alignment eyes on the scheduled alignment grid, while Version 1 keeps its bottom-right bootstrap alignment marker.

Advanced color calibration. RGB swatches plus structural black/white references support observed-palette matching, white balance, and a learned affine cross-channel correction. Every data cell keeps confidence plus a second hypothesis for Spectrum ECC 2.0.

Secure Payload v1. Optional AES-256-GCM authenticated encryption supports password-derived keys and exact raw 256-bit keys. Encryption sits above Spectrum ECC, so standard symbols keep their existing scan path.

Compact v1. The 21×21 symbol uses a reduced protected header and size-appropriate ECC, giving v1-M 24 payload bytes while retaining CRC-32.

This is a custom experimental symbology. Standard QR scanner apps cannot decode it.