Efficiently categorize bounced e-mails in your .NET Apps.

The Ultimate Bounce Inspector is a high-performance library that enables your .NET applications to easily inspect and categorize bounced e-mail messages with a few lines of code. Bounce Inspector can scan EML and Outlook MSG messages loaded from many sources such as local files, memory stream, IMAP and POP3 mailboxes. The inspection result can be used to update e-mail address lists, create e-mail campaign reports, etc.

Ultimate Message Scanner

Ultimate Bounce Inspector's Key Features

  • Parse and categorize bounced e-mail messages from many sources such as files, IMAP Inbox, POP3 Inbox easily
  • Supports thousands of different bounce formats
  • Detects many types of bounced message such as Hard, Soft, Temporary, Blocked, Generic, etc.
  • Custom bounce signatures/definitions can be easily added
  • On-the-fly hard bounced messages deletion
  • Inspection result can be used to update your e-mail lists, create reports, etc.
  • High-performance MIME parser component is included
  • Bounce Signature Database is updated and tested regularly
  • Supports EML file format
  • Supports Outlook MSG file format
  • Includes all mail message features
  • Includes all IMAP features
  • Includes all POP3 features
  • Includes all SMTP features
  • Support both task-based, event-based asynchronous and blocking (synchronous) application designs
  • Uniform and comprehensive error handling with .NET exceptions
  • Support for .NET Full Framework, Xamarin iOS, Mac, Android, Mono, .NET CF, and .NET Core & Standard
More Features with Code Examples

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Supported Platforms

List of the supported platforms

.NET Framework:
2.0, 3.0, 3.5. 4.0, 4.5.x, 4.6.x, 4.7; both 32-bit and 64-bit editions
OS: Windows XP or later
Visual Studio: 2008, 2010, 2012, 2013, 2015, 2017
Xamarin iOS:
Xamarin.iOS 8.6 or later; Xamarin Studio
Xamarin Android:
Xamarin.Android 4 or later; Xamarin Studio
.NET Core 2.0 or above (available soon)
.NET Standard 2.0 or above (available soon)
Universal Windows Platform (UWP)
Version: Windows 10 Mobile, Windows 10 Store Apps and Windows 10 IoT
OS: Windows
Mono and Xamarin Mac:
Version: 3.x, 4.x
OS: Linux, Apple macOS (OS X)
.NET Compact Framework:
2.0, 3.0, 3.5. 3.9
OS: Windows Mobile, Windows CE, Pocket PC, Windows Embedded Compact 2013
Visual Studio: 2008, 2012, 2013

Why Choose Ultimate BounceInspector

High-performance and reliable Bounce Inspector

When it comes to performance and reliability, Ultimate Bounce Inspector component for .NET outperforms all similar components on the market. In our performance test, BounceInspector takes only 10 to 20 milliseconds on average (Console Application running on a 2.4GHz PC with 1GB RAM) to scan a bounced e-mail message. In addition, the bounce signature database is regularly updated and you can get the updates by downloading and installing our new versions. If you encounter any unrecognized bounced e-mail messages, please do not hesitate to send us your bounced e-mail messages to support@componentpro.com or use our Feedback form to send your concerns to us. We provide you a hot-fix containing new bounce signatures that recognize the bounced e-mail messages you sent us within 1 business day.

Supports EML file format

When designing the Bounce Inspector component, we mainly focus on ease-of-use, performance, reliability, and flexibility. As a benefit, you only need a single line of code to scan thousands of bounced EML messages on local disk and get the accurate inspection result. You can either specify the path to the directory containing EML files or a list of EML file names to scan. BounceInspector does all the hard works for you.

The Ultimate Bounce Inspector also supports MIME and S/MIME, providing your applications the ability to encrypt, decrypt, sign, and validate e-mail messages.

Can scan mailboxes for bounced messages

Supports scanning IMAP and POP3 mailboxes

BounceInspector not only supports handling EML files, but it also supports scanning messages downloaded from IMAP or POP3 server. With this component, you can decide whether to download messages from the server to local disk or to memory stream to speed up your application performance. It also includes many convenient events which help you filter messages to be downloaded and inspected, providing your application with the greatest flexibility and high-performance.

Sending inspection report with SMTP classes

In addition to supporting downloading e-mail messages from IMAP and POP3 servers, BounceInspector also includes SMTP classes, which is essential for you when you need to send inspection reports to your e-mail address. The setup package comes with the full source code of the web sample projects which illustrate how to use this feature.

BounceInspector API is intuitive and easy-to-use

Intuitive and Fully Documented API

Connect, authenticate the user to the server and process bounced messages with a few lines of code using the intuitive API of ComponentPro's Ultimate BounceInspector. By using 100% managed code written in C#, the component takes advantage of the numerous built-in features of the .NET Framework to enhance performance. Moreover, the library is CLS compliant, and it does not use any unsafe blocks for minimal permission requirements.

Our classes are fully documented with detailed example code, which helps you shorten the learning curve. If your development environment is Visual Studio, enjoy the full integration of the online documentation. Just mark or select a keyword and press F1 in your Visual Studio IDE, the online documentation is represented instantly.


  • SMTP API is compliant with RFC 2821, 1891, 1893, 1985, 2034, 2197, 2554, 3030, etc.
  • POP3 API is compliant with RFC 1939, 2449, 1734, 1321, 2195, etc.
  • POP3 API is compliant with RFC 3501, 2683, 2359, 1321, etc.

Support Many Authentication Methods

In addition to basic username/password authentication, the Mail library also supports Auto, NTLM, GSSAPI, Digest-MD5, CRAM-MD5, Clear Text, and External authentication methods.

Some Examples:

PowerShell and SQL-SSIS

UltimateBounceInspector can be easily integrated with Powershell with some simple steps. You can also use it for SQL-SSIS package. Please see this topic for more details.

support powershell & sql-ssis

ASP.NET Medium Trust Support

You will find that almost all other competitors don't support Medium Trust environment, but our component does. The Medium Trust mode is forced by setting the MediumTrust security setting.

Task-based and Event-based Asynchronous Patterns

Our products support the latest Microsoft .NET Task-based Asynchronous Pattern introduced in .NET 4.5 Visual Studio 2012. Now you can write your asynchronous methods using the async and await (C#) or Async and Await (VB.NET) keywords. For some reason, if you would like to use the Event-based Asynchronous Pattern, we support it too.


Over 10,000 customers globally integrate our libraries in their applications


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