Create & Manage MSG Files via Open Source C# .NET Library
Free C# .NET MSG Email Library allows to Create, Read, Edit Manipulate and Send MSG Emails Without Relying on Microsoft Office or Outlook Interop Dependencies.
What is MsgKit?
For software developers working with Microsoft Outlook .msg files in .NET environments, MsgKit stands out as a lightweight, open-source, and flexible solution. MsgKit is a .NET library created by Sicos1977 that enables developers to generate MSG email files without relying on Microsoft Office or Outlook interop dependencies. This makes it particularly useful for server-side or cross-platform applications where installing Outlook isn't feasible.
MsgKit is written in C# .NET and provides deep control over the MSG file structure using low-level MAPI (Messaging Application Programming Interface) properties. Whether you're building a custom email archiving tool, migrating messages, or generating emails programmatically, MsgKit delivers a robust set of features. Unlike Microsoft.Office.Interop.Outlook, MsgKit is fully managed and doesn’t require Outlook to be installed. With support for MAPI properties, attachments, HTML/RTF bodies, and multiple recipients, it gives developers full control over the email file creation process. It is hosted on GitHub under the MIT License, making it perfect for both open-source and commercial use.
Getting Started with MsgKit
The easiest way to install MsgKit is via NuGet. To use it from Visual Studio’s Package Manager Console, please enter the following command.
install MsgKit via NuGet
Install-Package MsgKit Install MsgKit Library via GitHub
git clone https://github.com/Sicos1977/MsgKit.git Create MSG Files from Scratch via .NET API
The open source MsgKit library allows software developers to generate Outlook-compatible .msg files from scratch using .NET code. Developers can set all basic email properties such as subject, body, recipients, attachments, headers, and so on. The following code snippet sets the sender, subject, HTML body, and plain text content—all without needing Outlook installed.
How to Create MSG File via C# .NET API?
Message message = new Message(
new Sender("sender@example.com", "Sender Name"),
new Representing("representing@example.com", "Representing Name"),
"Test Subject",
"This is the HTML body of the message.",
"This is the plain text body of the message."
);
Support for To, Cc, and Bcc Recipients
The MsgKit library makes it easy for software developers to create and send email messages to multiple recipients with just a couple of lines of code. Adding multiple types of recipients is simple with MsgKit. You can specify To, Cc, and Bcc addresses programmatically. Here is a simple example that demonstrates how developers can generate emails in bulk or for archival purposes inside .NET applications.
How to Create and Send Email Messages to Multiple Recipients via C# API?
message.Recipients.AddTo("recipient@example.com", "Recipient Name");
message.Recipients.AddCc("cc@example.com", "CC Name");
message.Recipients.AddBcc("bcc@example.com", "BCC Name");
Add Rich Attachment to Emails via C# API
The open source MsgKit library has provided complete functionality for add and managing attachments to email messages inside .NET applications. The library supports adding various types of attachments—including binary files, embedded messages, and RTF data. Attachments can be inserted directly from streams or byte arrays. Developers can also control the attachment's MIME type and filename, ensuring compatibility with most email clients as shown in the following code example.
How to Add and Control Email Attachments via C# .NET API?
byte[] fileData = File.ReadAllBytes("sample.pdf");
message.Attachments.Add(new Attachment(
fileData,
"sample.pdf",
"application/pdf"
));
MAPI Metadata Preservation Support
The MsgKit library gives software developers full control over MAPI properties, making it suitable for applications that require granular email metadata preservation—such as compliance systems or email backup utilities. Developers can even extend the default behavior using custom MAPI properties for advanced scenarios.