Compliance Report

Every PDF that phpdftk generates passes validation by 5 independent, industry-standard tools. This isn’t a self-assessment — these are the same tools used by national archives, print production houses, and accessibility auditors to verify PDF correctness.

Results

275 tests. 275 passed. 0 failed. 0 skipped.

Tool	Tests	What it proves
QPDF	236	Every xref entry, page tree link, stream length, and object reference is structurally correct
Arlington	6	Every dictionary key and value type matches the PDF specification tables
veraPDF	2	PDF/A output meets ISO 19005 archival requirements
Matterhorn	6	PDF/UA output meets ISO 14289 accessibility requirements
JHOVE + Preflight + Security	25	Well-formed format, PDF/A cross-validation, zero security indicators

What each tool validates

QPDF — “Is this a correct PDF?”

236 tests cover the complete output surface. QPDF validates:

Cross-reference tables have exact 20-byte entries per ISO 32000-2
Page trees are correctly wired (parent/child/count consistency)
Stream /Length values match actual byte counts
Linearized PDFs have valid hint tables and partition offsets
Encrypted PDFs have correct handler structures
Object streams and xref streams pack correctly

Coverage: Simple text, all 26 annotation subtypes, bookmarks, forms, embedded fonts (TrueType, Type 1, OpenType CFF), graphics pipelines, shadings, patterns, multimedia, 3D, digital signatures, LTV signing, markup annotations, custom font form appearances, XMP metadata, linearized output, xref streams, object streams.

Arlington PDF Model — “Does this match the spec?”

The Arlington PDF Model is a machine-readable representation of every dictionary type in ISO 32000-2. It validates that every key is spelled correctly, every value has the right type, and every required field is present.

This catches the kinds of bugs that QPDF won’t — a /Filter value that should be a name but is a string, a missing /Type key, or a field that doesn’t exist in the spec for that dictionary type.

veraPDF — “Is this valid PDF/A?”

veraPDF is the reference implementation for ISO 19005 validation, developed with funding from the EU PREFORMA project. When phpdftk generates a PDF/A-1b document, veraPDF confirms it meets every clause — font embedding, color spaces, metadata identification, transparency prohibition, and encryption prohibition.

Matterhorn Protocol — “Is this accessible?”

The Matterhorn Protocol (via veraPDF’s UA-1 profile) validates PDF/UA compliance. Both positive and negative tests are included:

Tagged documents with proper structure pass
Annotations with /Contents alt text pass
Documents missing tagging, /Lang, DisplayDocTitle, or annotation alt text correctly fail

This proves the library produces genuinely accessible output, not just output that claims to be accessible.

JHOVE + pdfid + PDFBox Preflight

JHOVE confirms well-formed, valid PDF format (Open Preservation Foundation)
pdfid confirms zero suspicious security indicators — no embedded JavaScript, no auto-open actions, no launch triggers
PDFBox Preflight cross-validates PDF/A-1b against a second independent implementation

Corpus testing

Beyond validating our own output, the reader is stress-tested against 2,700+ PDFs from 5 major implementations:

Source	Files	Purpose
veraPDF corpus	~1,500	Intentionally non-conformant PDFs (negative testing)
QPDF test suite	~700	Linearization, encryption, xref streams, damaged files
PDFium (Chromium)	~300	Rendering, JavaScript, XFA, CJK
Apache PDFBox	~150	Signatures, forms, incremental updates
Poppler	~80	Fonts, transparency, damaged files

Running it yourself

# Full compliance suite (requires Docker)
mise run compliance

# Results written to docs/generated/compliance.md

The suite runs automatically on every push to main in CI. See Validation Suites for Docker setup and tool integration details.