Frequently Asked Questions
Quick answers to the questions developers and evaluators ask most. For a deeper enterprise-evaluation view, see TerraPDF for Enterprise.
Licensing & cost
Is TerraPDF really free for commercial use?
Yes. TerraPDF is MIT-licensed with no dual licensing, no community/commercial tiers, and no fees of any kind — per developer, per server, per document, or for SaaS deployment. You can use, modify, and redistribute it in closed-source commercial products.
Does TerraPDF collect telemetry or make network calls?
No. The library performs no network I/O of any kind — no telemetry, no license checks, no font or asset downloads. PDF generation is a fully in-memory operation, which also makes TerraPDF safe for air-gapped environments.
Compatibility & deployment
Which .NET versions and platforms are supported?
TerraPDF targets .NET 8, .NET 9, and .NET 10 and runs anywhere they do: Windows, Linux, and macOS, including Docker/Kubernetes containers, Azure App Service and Functions, and AWS Lambda. Because it is pure C# with no native binaries, behavior is identical across platforms and there are no platform-specific deployment steps.
Is TerraPDF thread-safe? Can I generate PDFs concurrently?
Generate as many documents in parallel as you like — the pattern is one document per thread or request, which is what ASP.NET Core gives you naturally. Treat each individual document build as single-threaded rather than sharing one document builder across threads.
Is the encryption FIPS-compliant?
TerraPDF implements no cryptographic primitives of its own. AES-256/AES-128 and SHA-2 operations use .NET's System.Security.Cryptography, which delegates to the underlying platform crypto libraries — so TerraPDF inherits whatever FIPS configuration your OS and .NET runtime enforce.
Capabilities & limits
Can TerraPDF read, edit, merge, or split existing PDFs?
No — TerraPDF generates new documents only. If you need to manipulate existing PDFs, pair it with a library built for that (for example, PDFsharp). See how TerraPDF compares.
Does TerraPDF support PDF/A or PDF/UA (accessibility)?
Not currently. Generated documents are standard PDF 1.7 (or PDF 2.0 when AES-256 encryption is enabled) without archival or tagged-accessibility conformance. If PDF/A is a blocker for you, please say so on GitHub issues — demand drives prioritization.
Can I embed custom fonts or render CJK, Cyrillic, or Arabic text?
Not yet. TerraPDF currently uses the built-in standard fonts (Helvetica, Times, Courier) with WinAnsi character coverage — printable ASCII, Windows-1252 typographic characters, and Latin-1 accented characters. Document metadata and bookmark titles do support full Unicode via UTF-16.
Can TerraPDF convert HTML to PDF?
No, and that's by design. TerraPDF is a code-first layout engine: you describe documents with a fluent C# API instead of maintaining HTML templates and a browser-based renderer. If HTML conversion is your requirement, a wkhtmltopdf- or Chromium-based tool is a better fit.
Project & support
How is TerraPDF versioned and supported?
Releases follow Semantic Versioning, with all changes documented in the changelog. The latest 1.x release receives fixes and security patches. Bugs and feature requests are tracked publicly on GitHub.
How do I report a security vulnerability?
Please don't file a public issue. Use GitHub private vulnerability reporting or email security@terrapdf.com. Response-time targets are published in the security policy.
How does TerraPDF compare to QuestPDF, iText, or PDFsharp?
Short version: TerraPDF is the lightweight, MIT-licensed, zero-dependency option for code-first document generation. QuestPDF offers richer rendering with commercial tiers and native assets; iText is a commercial-grade toolkit for enterprise PDF workflows under AGPL/commercial licensing; PDFsharp is lower-level drawing and manipulation. The homepage comparison table has the full breakdown.