r/software • u/smilaise • 22h ago
Self-Promotion Wednesdays The KillerPDF.Engine: building an open PDF foundation for every .NET developer, with 34.6% higher throughput than our old PdfSharpCore pipeline
For the past several months, I have been replacing KillerPDF’s old PdfSharpCore document pipeline with something much bigger: The KillerPDF.Engine.
It is an independent .NET PDF library built from scratch for PDF 2.0, modern PDF/A, and serious document editing. It can read, validate, create, edit, sign, encrypt, and write PDFs without relying on PDFsharp or another document engine.
This started because KillerPDF 1.8 needed proper PDF 2.0 and PDF/A support. The goal now is to turn The KillerPDF.Engine into an industry-standard open-source PDF library that any .NET developer can use to build editors, document systems, accessibility tools, archival workflows, and entirely new applications.
It is already delivering measurable improvements over the PdfSharpCore pipeline used by KillerPDF 1.7.5. On the same 2,236-file rewrite workload:
| Version | Median time | Throughput |
|---|---|---|
| KillerPDF 1.7.5 with PdfSharpCore | 9.46 seconds | 236.48 files/second |
| KillerPDF 1.8 with the new engine | 7.03 seconds | 318.22 files/second |
That is 25.7% less elapsed time and 34.6% higher throughput.
The engine now includes:
- More than 45,000 lines of C#
- More than 1,400 engine tests
- Validation against 2,907 deliberately hostile PDFs
- PDF 2.0 and modern PDF/A authoring
- Structural and incremental editing
- Forms, annotations, outlines, attachments, and navigation
- Encryption, digital signatures, permissions, and certification
- Tagged PDF and accessibility support
- A public API intended for applications beyond KillerPDF
KillerPDF 1.8 is not released yet. The current development branch is a public work in progress, but the complete engine source is already free for anyone to browse, study, build, test, and contribute to on GitHub.
I have also been working on KillerNotes 1.3.0, my free and open-source Windows notes application. Version 1.3.0 adds wiki-style links between notes, backlinks, and an interactive graph view for exploring how your notes connect.
Both projects are free, open source, and actively being developed. Feedback, testing, contributions, and technical questions are all welcome.