MiniPdf 0.38.4

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A minimal, lightweight .NET library for converting office files to PDF.

Online Demo: https://mini-software.github.io/MiniPdf/

Features

• Excel to PDF conversion (.xlsx)
• Word to PDF conversion (.docx)
• PowerPoint to PDF conversion (.pptx)
• LLM-friendly Markdown, JSON, and semantic model extraction from .xlsx, .docx, and .pptx
• PDF merge with top-level bookmarks
• Minimal dependencies — lightweight; relies almost entirely on built-in .NET APIs
• Serverless-ready — no COM, no Office installation, no Adobe Acrobat — runs anywhere .NET runs
• Valid PDF 1.4 output
• 100% open-source & free — Apache 2.0 licensed, commercial use welcome; just keep the attribution. PRs & contributions are even better!

Install

dotnet add package MiniPdf

Usage

using MiniSoftware;

// Excel to PDF
MiniPdf.ConvertToPdf("data.xlsx", "output.pdf");

// Word to PDF
MiniPdf.ConvertToPdf("report.docx", "output.pdf");

// PowerPoint to PDF
MiniPdf.ConvertToPdf("slides.pptx", "output.pdf");

// File to byte array
byte[] pdfBytes = MiniPdf.ConvertToPdf("data.xlsx");

// Render selected Excel sheets by name or 1-based index (null renders all sheets)
MiniPdf.ConvertToPdf("data.xlsx", "selected.pdf", sheets: new[] { "Summary", "Details" });
MiniPdf.ConvertToPdf("data.xlsx", "selected.pdf", sheetIndexes: new[] { 1, 3 });

// Stream to byte array
using var stream = File.OpenRead("data.xlsx");
byte[] pdfBytesFromStream = MiniPdf.ConvertToPdf(stream);

// Merge PDFs and add bookmarks
MiniPdf.MergePdf(new[] { "cover.pdf", "body.pdf" }, "merged.pdf", new PdfMergeOptions
{
  BookmarkTitles = new[] { "Cover", "Body" },
  Bookmarks = new[] { new PdfBookmark("Body page 2", 2) },
});

LLM-Friendly Content Extraction

MiniPdfDocumentContent content = MiniPdf.ExtractContent("report.docx");
string markdown = MiniPdf.ConvertToMarkdown("report.docx");
string json = MiniPdf.ConvertToJson("report.docx");

MiniPdf.ConvertToJson("data.xlsx", "data.json", new MiniPdfContentOptions
{
  Sheets = new[] { "Summary" },
  MaxRows = 200,
  MaxColumns = 20,
});

The deterministic JSON schema starts at version 1. Extraction preserves source order, headings, paragraphs, lists, tables, worksheet cell addresses, hyperlinks, DOCX footnotes, and image/chart metadata. It does not perform OCR or export image sidecar files. Comments, tracked changes, threaded comments, and PowerPoint speaker notes are not yet extracted.

PDF Merge Usage

Merge Files

using MiniSoftware;

MiniPdf.MergePdf(
  new[] { "cover.pdf", "chapter-1.pdf", "chapter-2.pdf" },
  "book.pdf");

Input order is preserved, so pages from cover.pdf appear first, followed by chapter-1.pdf, then chapter-2.pdf.

Add One Bookmark Per Source PDF

Use BookmarkTitles when each input PDF should become a top-level bookmark. The number of titles must match the number of input PDFs.

MiniPdf.MergePdf(
  new[] { "cover.pdf", "chapter-1.pdf", "chapter-2.pdf" },
  "book-with-bookmarks.pdf",
  new PdfMergeOptions
  {
    BookmarkTitles = new[] { "Cover", "Chapter 1", "Chapter 2" },
  });

Add Bookmarks To Specific Pages

Use PdfBookmark for explicit page targets. PageIndex is zero-based and refers to the final merged PDF.

MiniPdf.MergePdf(
  new[] { "cover.pdf", "chapter-1.pdf", "chapter-2.pdf" },
  "book-with-custom-bookmarks.pdf",
  new PdfMergeOptions
  {
    Bookmarks = new[]
    {
      new PdfBookmark("Start", 0),
      new PdfBookmark("Chapter 2 - page 3", 8),
    },
  });

Return A Byte Array

byte[] mergedPdf = MiniPdf.MergePdf(
  new[] { "cover.pdf", "chapter-1.pdf" },
  new PdfMergeOptions
  {
    BookmarkTitles = new[] { "Cover", "Chapter 1" },
  });

Supported inputs are unencrypted PDFs that use classic xref tables. Encrypted PDFs and xref-stream-only PDFs throw NotSupportedException.

Benchmark

MiniPdf output is compared against LibreOffice as the reference renderer across 373 test cases.

Detailed reports:

• XLSX Benchmark Report
• DOCX Benchmark Report
• Issue Files Xlsx Report
• Issue Files Docx Report

Links

• Source code: https://github.com/shps951023/MiniPdf
• License: Apache-2.0