Send PDF Files over Telegram in C#/.NET - Complete Guide

Automate Telegram Document Sharing with C#/.NET

Looking to automate PDF delivery, document notifications, or file sharing from your C#/.NET applications? This guide walks you through sending PDF files to Telegram users using C# and the WhatsMate Telegram Gateway REST API. Perfect for .NET developers, Windows application builders, and automation enthusiasts who want to integrate document delivery into their C#-based workflows.

Note for Visual Studio 2022 users: If you’re using Visual Studio 2022, please read this updated tutorial instead.

📋 Prerequisites

Before you begin, ensure you have:

1. A WhatsMate Telegram Gateway account - Required for API access
2. Recipient registration - Each recipient must register with the Gateway first
3. Visual Studio 2019 - .NET development environment (or compatible IDE)
4. Basic C# knowledge - Familiarity with C# programming and .NET framework
5. PDF file ready - Have the document you want to send available locally
6. System.Web.Extensions reference - Required for JSON serialization

⚠️ Important: Recipients must register with the WhatsMate Telegram Gateway before they can receive messages. Unregistered users will not receive any messages from the Gateway. Registration instructions are available on the official WhatsMate site.

📝 Step-by-Step Implementation

Follow these steps to send your first PDF document to a Telegram user from a C# application:

1. Copy the C# Code Template

Start by copying the following source code into your C# file:

2. Configure a few Parameters

Customize these key parameters in the C# code:

• Lines 10-12: Replace YOUR_INSTANCE_ID, YOUR_CLIENT_ID_HERE, and YOUR_CLIENT_SECRET_HERE with your gateway instance ID, Client ID, and Secret
• Line 20: Replace 12025550105 with the target phone number (including the country code)
• Line 22: Replace C:\\TEMP\\subwaymap.pdf with the path to your PDF file
• Line 23: Replace anyname.pdf with the desired filename for the document
• Line 24: Replace Check this out with an optional caption for your PDF

3. Add Required Reference

Ensure your project references System.Web.Extensions for JSON serialization:

1. Right-click on References in Solution Explorer
2. Select Add Reference
3. Find and check System.Web.Extensions
4. Click OK

4. Send Your PDF Document

Build and run your C# application in Visual Studio to deliver your PDF to Telegram.

🔧 Common Use Cases

This automation approach is ideal for:

• Automated report delivery - Send daily/weekly PDF reports to Telegram from C# applications
• Document sharing automation - Deliver invoices, receipts, or contracts via Telegram using C#
• System documentation - Share configuration files or logs as PDF documents from .NET systems
• Educational content - Distribute learning materials or tutorials through Telegram from C# apps
• Integration with .NET document generation - Combine with C# libraries that create PDFs for Telegram delivery

🚀 Get Started Today

Ready to automate your document sharing over Telegram with C#? You’ll need a trial account to access the API. Sign up for a 2-week trial and start sending PDF files within minutes!

Next Steps: Once you’ve mastered basic PDF sending, explore advanced features like sending images, audio files, or group messages through the WhatsMate Telegram Gateway API documentation.