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QR payload density and error-correction preflight

What does the current QR generator actually produce, and which capacity and recovery limits still require final-device testing?

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Recorded output for QR payload density and error-correction preflight
Recorded first-party output associated with this report.

Test environment

Recorded browser-generated PNG; independent decode of the saved output. The public tool uses error-correction level H and a 180 × 180 canvas.

Fixture and expected result

The saved QR decodes to the exact controlled destination and retains a clear surrounding margin. Longer payloads should be treated as denser symbols, not assumed to fit the same print size.

Reproduction steps

  1. Download the recorded QR PNG and payload list.
  2. Decode the PNG with an independent scanner.
  3. Generate each supplied payload and compare visual density.
  4. Scan the final downloaded or printed artifact at its intended size.

Observed result

The recorded PNG was independently decoded to https://nevco.online/. The report fixture supplies short, URL, and Unicode payloads for repeat checks; the current UI does not expose a correction-level selector.

Downloadable evidence

The fixture library publishes SHA-256 hashes for exact-byte verification.

What this test does not establish

One successful computer decode does not establish camera, printer, paper, lighting, distance, damage, or every payload capacity. The tool fixes correction level at H.

Related tool and guide

QR Code Generator · QR Codes That Scan Reliably

Change history

  • : Structured data, image dimensions, and fixture links reviewed.
  • : Report organized under Anvil Tools Lab; evidence and limitations reviewed.