What is PDF preflight?
Preflight is the quality-control step that catches document errors before they print and mail. Drop a file for a free structural scorecard — no signup.
Works on all five. Spec-traceable compliance modules: PDF (USPS, Accessibility, Print, Brand) · AFP / MO:DCA (USPS).
Free analyzer · structural parse + summary · v1
The free scorecard parses structure only — it does not run compliance checks. The compliance modules (the actual findings) run in a workspace.
What is PDF preflight?
Preflight is the document QC step that catches errors before they print and mail — so you ship clean files instead of reprints. A preflight tool parses the file, validates it against the relevant specifications, and reports problems — missing fonts, low-resolution images, wrong color spaces, broken geometry, or non-compliant metadata — while they are still cheap to fix.
The term comes from print prepress, but modern document QC spans far more than a single PDF. Production teams ship in five formats — PDF, AFP / MO:DCA, PCL, PostScript, and IPDS — and each carries its own structural rules. A preflight that only understands PDF leaves the rest of the transactional and direct-mail pipeline unchecked.
Good preflight is deterministic and spec-traceable: every finding maps back to a named requirement (USPS IMb integrity, PDF/UA structure, PDF/X print rules, a brand template baseline) rather than a vague warning. That makes results reproducible across runs and defensible in an audit — which is exactly what a regression diff between two versions of a document gives you.
What preflight actually checks
A structural scorecard parses the file; compliance modules turn each rule into a pass, fail, or advisory you can trace back to the spec.
Frequently asked questions
The short answers to what print and mail teams ask about preflight.
Is preflight the same as proofreading?
No. Proofreading checks the content — spelling, grammar, copy. Preflight checks the file — its structure, fonts, images, color, geometry, and standards conformance — so it prints and mails correctly. They are complementary: proofreading catches a typo; preflight catches a missing font or an invalid mail barcode.
What file formats can be preflighted?
Five: PDF, AFP / MO:DCA, PCL, PostScript, and IPDS. All five get the structural scorecard + regression diff; the deterministic compliance modules run on PDF (all four modules) and AFP (USPS).
What’s the difference between PDF/X, PDF/A, and PDF/UA?
PDF/X is for print production (predictable color, embedded fonts, no surprises on press). PDF/A is for archiving (long-term, self-contained files). PDF/UA is for accessibility (tagged structure, reading order, alt text). Preflight validates PDF/X (print module) and PDF/UA plus WCAG 2.2, Section 508 and EN 301 549 (accessibility module); PDF/A archival validation is not part of Preflight today.
Do I need to sign up to run a preflight?
No. The free structural scorecard runs with no signup — drop a file and get a parse + summary. The compliance modules (the pass/fail findings) run in a workspace, which needs an account.
What is a regression diff?
It compares a new version of a document against an approved baseline and reports what changed — so you catch unintended changes (a shifted barcode, a swapped font, a moved disclosure) before they reach print or mail.