ZPL Diagnostics Hub

How to run a full ZPL health check

1. Paste the ZPL exactly as your application sends it to the printer — a spool file, an integration log or a template export all work.
2. Press Run diagnostics. The report is built from the same engine that powers the editor: structure rules, parameter checks, barcode data rules, font checks and the size/DPI analyzer run in one pass.
3. Read the sections top to bottom. Each one carries a badge: Clean, Findings (with line numbers and messages), or Not assessed with the reason — for example, barcodes are only judged when the label actually contains a barcode command.
4. Check the score last, not first. It is computed only from the assessed sections with an explicit formula shown under the number, so a high score never hides an unmeasured area.

When this is the right tool

Use the hub when a label misbehaves and you do not yet know which layer is at fault: a format that never prints (structure), text that lands outside the label (size or offsets), a barcode the scanner rejects (data rules), missing characters (fonts and encoding) or a printer that stalls on large jobs (graphics memory). Instead of running five separate checks, one paste shows all of them side by side, and the sections that could not be measured say so instead of pretending to be green.

Frequently asked questions

• What does "Not assessed" mean? — It means the section had nothing measurable to judge: no barcode command, no printer model given, or a size that could not be derived. Those sections are excluded from the score entirely — counting them as healthy would fabricate confidence, counting them as broken would fabricate failure.
• How is the score calculated? — 100 minus 15 per error, 5 per warning and 5 per section-level caution, floored at zero, over the assessed sections only. The formula is printed under the score so the number is never a black box.
• Is this different from the editor's diagnostics? — Same engine, different shape. The editor shows findings inline while you type; the hub groups everything by topic — syntax, size/DPI, orientation, barcodes, fonts, memory, job behaviour — so you can hand one report to a colleague or a supplier.