EPL Validator

How to validate EPL code

1. Paste the EPL job and press Render — findings are listed with line numbers.
2. Errors (unknown command, missing fields, empty barcode data) mean the line will not print what you expect.
3. Warnings (font or barcode type outside the MVP set, invalid rotation) mean the preview substitutes or skips something.
4. Info entries mark printer-behaviour commands (speed, darkness) that do not affect the image.

When this is the right tool

Run it before sending EPL to production printers, after hand-editing a legacy job, or when a label prints blank or misplaced and you suspect a malformed line. It checks structure against the same command registry the viewer renders from, so what the validator accepts, the viewer can draw.

Frequently asked questions

• Does a clean result guarantee a correct label? — No: it means the MVP checks passed. Data-level mistakes (wrong tracking number) are yours to verify — the barcode verifier can read back a printed label.
• Why is a valid EPL command reported as unknown? — The validator's registry equals the preview's coverage. A command outside the MVP is honestly reported instead of silently accepted.
• Are errors and warnings different? — Yes: errors will not render at all; warnings render with a substitution or omission that is spelled out in the message.