Questions, answered.

Core is the free, open-source (Apache-2.0) PDF 2.0 engine: generation, HTML-to-PDF, PDF/UA-2 tagging, and baseline PAdES B-B signatures. Pro adds specialty barcodes, charts, templates, redaction, and B-T timestamped signing. Enterprise adds the long-term signature levels (B-LT / B-LTA), HSM / PKCS#11 hardware keys, PDF/A-4 archival, ZUGFeRD / Factur-X e-invoicing, and forensics. Every tier is the same in-process engine — you move up without a rewrite. See the full edition comparison.

No — Connect is the access surface, not a capability tier. It exposes the engine over MCP, REST, and gRPC for AI systems and services, and soft-loads whatever Pro / Enterprise capabilities you have installed. It is free and Apache-2.0. See Connect.

Generate ISO 32000-2 (PDF 2.0) documents from HTML and CSS, emit PDF/UA-2 tagged structure, apply baseline PAdES B-B signatures, and expose it to AI agents through Connect — all under Apache-2.0, in your own process. Try it in five minutes; the commercial terms live on pricing.

NextPDF produces output that targets and supports conformance with the standards (PDF 2.0, PDF/UA-2, PDF/A-4, PAdES, EN 16931) and emits the real structures they require. Formal conformance is always the verdict of an external validator on your data — not a claim NextPDF makes for you. Every standard ships with the exact command to check it yourself: see how to verify.

They are the PAdES baseline levels, each adding longevity. B-B (Core) binds the document to the signer with a CMS SignedData container. B-T (Pro) adds an RFC 3161 trusted timestamp — proving when it was signed. B-LT (Enterprise) embeds the validation material (the DSS) so it still verifies after the signing certificate expires. B-LTA (Enterprise) adds renewable archival timestamps for decades-long verifiability. See signed agreements.

Run it through your own tools: qpdf --check for structure, veraPDF for PDF/UA or PDF/A, OpenSSL for the signature, and pdfdetach for embedded e-invoice XML. Every sample on the showcase is a real, sha256-pinned file you can download and validate — we would rather you check than take our word.

ZUGFeRD / Factur-X hybrid invoices use the PDF/A-3 container because it permits embedded files — the structured EN 16931 XML lives inside the human-readable PDF. Standalone archival output targets the newer PDF/A-4 (ISO 19005-4). Different jobs, different profiles.

PDF/UA-2 (ISO 14289-2) is the accessibility profile: the document carries a tagged logical structure — headings, reading order, figure alternative text, and a document language — so assistive technology navigates the meaning, not just the pixels. NextPDF emits the conformant structure; meaningful alt text and reading order remain your editorial responsibility.

PHP 8.4 or newer in the 8.x line (the engine targets 8.4 up to but not including 9.0; PHP 9 is not yet supported) and Composer — that is it for Core. It renders in your own PHP process: no separate browser service to deploy, scale, or secure. It is worker-safe by design (Octane, FrankenPHP, RoadRunner) and runs at the edge. The engine is held to PHPStan Level 10.

Not for the core HTML-to-PDF path — NextPDF renders in-process. For pixel-perfect CSS3 (Flexbox, Grid, web fonts) you can opt into the Artisan extension (Chrome over the DevTools Protocol) or render at the edge with the Cloudflare extension, but neither is required for standard documents. See integrations.

Yes — the nextpdf/backport distribution is an automated PHP 8.1+ (or 7.4+, core only) downgrade build of the ecosystem. The native packages target PHP 8.4 or newer in the 8.x line. See the backport.

Yes. The same engine generates, signs, tags, and archives inside your PHP process, so a document never hops between a renderer, a signer, and a converter. That is the architectural difference from browser-service approaches. See why NextPDF.