Aspose.Email  for .NET

Add Text Watermark to MSG via C#

Build your own .NET apps to watermark MSG files using server-side APIs.

How to Watermark MSG File Using C#

In order to watermark MSG file, we’ll use

Aspose.Email for .NET

API which is a feature-rich, powerful and easy to use document manipulation API for C# platform. Open


package manager, search for Aspose.Email and install. You may also use the following command from the Package Manager Console.


PM> Install-Package Aspose.Email

Steps to Add Watermark to MSG via C#

You need the


to try the following workflow in your own environment.

  • Load the HTML body of email message file
  • Load attachment and set its content
  • Set body content, if any
  • Save email file on disc

System Requirements

Aspose.Email for .NET is supported on all major operating systems. Just make sure that you have the following prerequisites.

  • Microsoft Windows or a compatible OS with .NET Framework, .NET Core, and Xamarin Platforms.
  • Development environment like Microsoft Visual Studio.
  • Aspose.Email for .NET referenced in your project.

Add Watermark to MSG - C#

mail.Attachments.Add("watermark", imageBytes);

var html = mail.BodyHtml;
var htmlDocument = new Aspose.Html.HTMLDocument(mail.BodyHtml, "");

var attachment = mail.Attachments.Find(x => x.LongFileName == "watermark");

var bodyHtml = htmlDocument.Body.InnerHTML;

var watermarkHtml = $@"watermarkHtml";

htmlDocument.Body.InnerHTML = watermarkHtml;

var folderPath = Path.Combine(Config.Configuration.OutputDirectory, Guid.NewGuid().ToString());
var filePath = Path.Combine(folderPath, "Merged.html");


var content = System.IO.File.ReadAllText(filePath);

Directory.Delete(folderPath, true);

mail.SetBodyContent(content, BodyContentType.Html);  
  • About Aspose.Email for .NET API

    Aspose.Email is a Microsoft Outlook and Thunderbird formats parsing solution. One can easily create, manipulate, convert email and storage formats such as MSG, EMLX, EML and MHT. Handling of email attachments, customization of message headers and implementation of different network protocols like POP3, IMAP & SMTP to send & receive emails is much easier. Its a standalone API and does not require Microsoft Outlook or any other software installation.

    Watermark MSG via Online App

    MSG What is MSG File Format

    MSG is a file format used by Microsoft Outlook and Exchange to store email messages, contact, appointment, or other tasks. Such messages may contain one or more email fields, with the sender, recipient, subject, date, and message body, or contact information, appointment particulars, and one or more task specifications. The properties that constitute the Message object, including are also a part of the MSG file. MSG file has headers, main message body, and hyperlinks as plain ASCII text. MSG files are also suitable with the programs that need Microsoft's Messaging Applications Programming Interface (MAPI).

    Read More

    Other Supported Watermarking Formats

    Using C#, one can easily watermark different formats including.

    EML (Outlook Email Messages)