FAQ — Aspose.PDF FOSS for .NET

Licensing & Open Source

What is the licensing model for Aspose.PDF FOSS for .NET?

Aspose.PDF FOSS for .NET is released under the MIT License. You may use, copy, modify, and distribute the library free of charge, including in commercial products, without purchasing a commercial license. The source code is publicly available on GitHub.

Can I use Aspose.PDF FOSS for .NET in commercial software?

Yes. The MIT License permits use in proprietary and commercial applications with no runtime fees. You are only required to retain the license notice in any distributed copy or substantial portion of the library.

Do I need an Aspose license key or metered license?

No license key is required for Aspose.PDF FOSS. The Document.IsLicensed property reflects internal licensing state but no activation step is needed — the library runs fully unlicensed at no cost.

Installation & Requirements

How do I install Aspose.PDF FOSS for .NET?

Install from NuGet using the .NET CLI:

dotnet add package Aspose.Pdf.Foss --version 0.1.0-alpha

Or add to your project file:

<PackageReference Include="Aspose.Pdf.Foss" Version="0.1.0-alpha" />

What .NET version is required?

Aspose.PDF FOSS targets .NET 8 and later. It does not support .NET Framework, .NET Standard, or earlier .NET Core versions. Confirm your project targets net8.0 or higher in the .csproj file.

Are there any native dependencies or external tools required?

No. Aspose.PDF FOSS is a fully managed .NET library with no unmanaged native binaries and no dependency on Adobe Acrobat, Ghostscript, or any other external tool.

Format Support

Which formats does Aspose.PDF FOSS for .NET support?

The library reads and writes the PDF format. The Document.Open method accepts byte arrays, file paths, and streams. The Document.Save and Document.ToArray methods produce PDF output. Image output (for rendering pages) is governed by the ImageFormat enum, which supports BMP, GIF, JPEG, PNG, TIFF, and other raster formats.

Can Aspose.PDF FOSS convert PDF pages to images?

Yes. Page rendering to raster formats is supported via the ImageFormat enum, which includes Bmp, Jpeg, Png, Gif, Tiff, and Emf members. Specific device classes handle the rendering pipeline.

API Usage

How do I create a new PDF document?

Use Document.Create() to produce an empty document, then add pages and save:

using var doc = Document.Create();
// add pages, content, annotations
using var ms = new MemoryStream();
doc.Save(ms);
byte[] pdfBytes = ms.ToArray();

How do I open an existing PDF from a file path or byte array?

// From file path
using var doc = Document.Open("input.pdf");
// From byte array
byte[] data = File.ReadAllBytes("input.pdf");
using var doc = Document.Open(data);
// From stream
using var stream = File.OpenRead("input.pdf");
using var doc = Document.Open(stream);

How do I merge multiple PDF documents?

Use Document.Merge to combine multiple documents:

var merged = Document.Merge(new[] { doc1, doc2, doc3 });
merged.Save("combined.pdf");

Document.MergeDocuments is an equivalent overload that accepts file paths directly.

Known Limitations

Is the library feature-complete compared to Aspose.PDF commercial edition?

No. Aspose.PDF FOSS is an open-source subset. Some advanced commercial features — such as full XFA form rendering, PDF/A conversion, digital signatures (PKCS7), and certain linearisation operations — may be partially implemented or absent. Check the GitHub issue tracker for the current status of specific features.

Are AcroForm JavaScript extensions fully supported?

The FieldDateTimeFormatter, FieldNumberCurrencyFormatter, and FieldNumberPercentFormatter classes implement the PDF JavaScript AF_Date_Format, AF_Number_Format, and AF_Percent_Format function equivalents for server-side field formatting without a JavaScript engine. These are available in the current alpha release.