SelectPdf 26.5 adds remote engine, form fields and HSM signing

SelectPdf released version 26.5 of its cross-platform .NET PDF library, adding a remote conversion engine, automatic tables of contents, HTML-to-PDF form field creation and hardware-backed signing. The update also expands Linux support, improves performance and gives teams a path off wkhtmltopdf without rewriting code.

Why it matters: - SelectPdf 26.5 aims to make .NET PDF workflows easier to run across modern infrastructure, including containers, clusters and Alpine Linux. - The release also targets teams that need accessibility, long-term signature validation, and a cleaner migration away from wkhtmltopdf.

What happened: - SelectPdf released version 26.5 of SelectPdf.Universal, its cross-platform .NET PDF library and HTML to PDF converter. - The library runs on Windows, Linux and macOS on Apple Silicon. - The update adds a remote engine, automatic tables of contents, HTML form-to-PDF form conversion, hardware-key signing, faster parallel conversions and compatibility packages for wkhtmltopdf-based applications.

The details: - The remote engine can run in the ghcr.io/selectpdf/engine container on another machine instead of on the application host. - The remote engine removes the need for a native engine package and brings SelectPdf to Alpine Linux and other musl-based systems. - The engine image is available for linux/amd64 and linux/arm64. - A Helm chart and tested setups are included for Docker Compose, Azure Container Apps, Amazon ECS, Google Cloud Run and Kubernetes. - In the commercial library, HTML to PDF, HTML to image, PDF to text and PDF to image all run through the remote engine. - The free SelectPdf Community Edition also supports the remote engine. - A new TableOfContents option can build a table of contents during HTML to PDF conversion in three ways. - The library can add leaders and page numbers to an existing table of contents on the page. - The library can generate a table of contents from headings. - The library can insert separate table of contents pages at the start, after the first page or at the end. - Table of contents generation works with right-to-left and non-Latin pages, plus headers and footers. - With CreateFormFields, text inputs, check boxes, radio buttons, drop-down lists and text areas become PDF form fields at the position of each control. - The form fields retain values, labels and options. - Form-field creation also works with PDF/A and PDF/UA output. - SelectPdf.Universal can sign with a key held in an HSM, smart card or USB token through PKCS#11. - The library can also sign with a certificate from the Windows, macOS or Linux certificate store. - A remote signing service can complete signing in two steps. - Signing was verified with a qualified certificate on a USB token, and Adobe Acrobat reports the result as a qualified electronic signature. - Long-term validation, or PAdES B-LT, embeds revocation data for the certificate chain so signatures can still be validated after certificates expire. - Signatures can use SHA-256, SHA-384 or SHA-512. - Visible signatures can include a company logo. - The release adds PDF/A-1a, PDF/A-2a and PDF/A-2u output. - SelectPdf already supported PDF/A, PDF/X and accessible PDF/UA-1 and PDF/UA-2 output. - PDF/A-1a pairs with PDF/UA-1. - Parallel conversions run faster in 26.5. - SelectPdf said tests showed conversions per minute more than doubled on Linux and rose by about half on Windows, with the exact gain depending on the machine. - Long HTML documents convert faster. - Saving a loaded document now takes a fraction of the previous time. - ImagesMaxResolution resamples oversized images to reduce file size. - FitWideContent scales content wider than the page instead of cutting it off on the right edge. - Text search now finds Chinese, Japanese, Korean, Hindi, Thai and Arabic terms. - Text elements now shape Indic, Thai and other complex scripts. - Four compatibility packages preserve the APIs of DinkToPdf and Haukcode.WkHtmlToPdfDotNet while rendering with Chromium instead of wkhtmltopdf's Qt WebKit. - The packages are SelectPdf.Compat.DinkToPdf, SelectPdf.Compat.DinkToPdf.Licensed, SelectPdf.Compat.WkHtmlToPdfDotNet and SelectPdf.Compat.WkHtmlToPdfDotNet.Licensed. - Existing converter code can build as-is. - Layouts keep their size, headers and footers stay in place, and applications no longer need to ship native wkhtmltopdf files. - The compatibility packages are open source under the MIT license on GitHub. - The commercial library and the Community Edition can now be installed with a single package per platform. - The platform-specific packages are Windows, Linux x64, Linux ARM64 and macOS on Apple Silicon. - For the Community Edition, the packages are SelectPdf.HtmlToPdf.Windows, SelectPdf.HtmlToPdf.Linux, SelectPdf.HtmlToPdf.Linux.Arm64 and SelectPdf.HtmlToPdf.MacOS. - For the commercial library, the packages are SelectPdf.Universal.Windows, SelectPdf.Universal.Linux, SelectPdf.Universal.Linux.Arm64 and SelectPdf.Universal.MacOS. - A new result property tells an application when the 5-page limit shortens a document. - SelectPdf.Universal targets .NET 8, .NET 10 and .NET Standard 2.0. - The library runs from .NET Framework 4.6.1 to current .NET releases. - Version 26.5 is also verified with .NET 11 RC 1 on Windows, Linux x64 and ARM64, and macOS on Apple Silicon. - SelectPdf 26.5 is available now on NuGet as SelectPdf.Universal for commercial users and SelectPdf.HtmlToPdf.Universal for the free Community Edition. - Native engine packages and compatibility packages are also available. - One perpetual license starts at $499 for a single developer and covers both the cross-platform SelectPdf.Universal and the classic Windows library. - A free trial is available. - SelectPdf has been downloaded more than 23 million times from NuGet. - SelectPdf is a brand of Outside Software SRL in Bucharest, Romania.

Between the lines: - The release positions SelectPdf as a broader infrastructure layer, not just a PDF converter, by bundling container support, signing workflows and migration tools in one update. - The wkhtmltopdf compatibility packages suggest SelectPdf is trying to capture teams that want Chromium rendering without rewriting converter code. - Better Arabic, Indic and East Asian text handling, plus PDF/UA and PDF/A updates, point to a push toward compliance-heavy and multilingual use cases.

What's next: - Teams using wkhtmltopdf wrappers can switch to the new compatibility packages without changing their converter API calls. - Developers deploying on Alpine Linux or mixed container environments can route conversions through the remote engine. - Users who need archival or regulated signatures can adopt the new PDF/A, PAdES B-LT and hardware-backed signing options.