The Anvil SDK for C# & .NET

Build document workflows in C# with the Anvil SDK. Generate PDFs, fill templates, and collect e-signatures from one package.

C# & .NET SDK on GitHub API Documentation

Products

Click on a product to view documentation.

PDF Generation

Generate pixel-perfect PDFs from HTML, CSS, or Markdown with a single API call.

PDF Fill

Fill existing PDF templates programmatically. Send data, get back a completed document.

Etch

Request legally binding e-signatures on any document. Collect signatures from any device.

C# & .NET SDK features

Rate and concurrency limits are respected for you, so bursts of requests queue instead of failing.

Get started

Installation

The Anvil package is MIT-licensed and maintained in the open on GitHub.

$ dotnet add package Anvil

Set-up with Claude

Let Claude build your integration

Install the Anvil Document SDK plugin in Claude Code and Claude will scaffold the SDK into your codebase — discovery, planning, and production-ready code.

/plugin marketplace add anvilco/anvil-plugins
/plugin install anvil-document-sdk@anvil-plugins

No API key setup needed. The plugin connects to your Anvil account with OAuth and logs you in automatically.

Why Anvil

We're fast

Generate, fill, and e-sign PDFs in a single API call, whether it's one document or a million.

Flexibility

Generate PDFs from HTML or Markdown, fill existing templates, and request signatures on any of them, all from the same SDK.

Easy-to-use

Install the package, add your API key, and make your first request in minutes. The SDK is MIT-licensed and maintained in the open on GitHub.

Compliant

SOC 2 Type 2 certified, HIPAA-eligible with a BAA, and GDPR-ready. Documents are processed in-memory and never persisted unless you ask us to store them.

Get a demo
(from a real person)

Schedule some time on our calendar to talk through your specific use case and see which Anvil products can help.

Want to try Anvil first?

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