MailBee.NET SMTP Component

MailBee.NET SMTP Component

Compose, mail merge, and send e-mails directly to recipients or via SMTP server
MailBee.NET Objects bundle includes SMTP, POP3, IMAP, EWS, Security, Antispam, Outlook Converter, Address Validator, PDF components and also BounceMail, HTML, MIME, ICalVCard components which are a free functionality.

MailBee.NET SMTP Component is a reliable and robust solution for composing, mail merge, and sending e-mails in .NET applications. This includes sending a web page, sending with or without SMTP relay server, support of backup SMTP and DNS servers for bulletproof e-mail delivery, ESMTP support, re-sending and forwarding e-mails received with other MailBee.NET components, and much more. Backed with commercial-grade support.

MailBee.NET SMTP bundle includes a set of MIME objects such as MailMessage and Attachment which are used for constructing e-mails. It fully supports the modern async/await API for building scalable and responsive applications.

Visual Studio


Written in 100% managed code, MailBee.NET Objects only require the .NET framework be installed on the computer.

MailBee.NET Objects can be used in any .NET language including C# and VB.NET. Supported .NET frameworks include .NET 2.0/3.0/3.5/4.0/4.5/4.6/4.7/4.8, both 32-bit and 64-bit.

MailBee.NET also supports .NET Core 1.0/2.0/3.0/3.1, .NET 5.0/.NET 8.0 and newer including ASP.NET Core and Xamarin, UWP (Universal Windows), Azure.

You also get these MailBee.NET components for free: BounceMail, HTML, MIME, ICalVCard.

Top 100 publisher by ComponentSource

Over the years, MailBee.NET Objects has been among bestsellers on ComponentSource, the world's leading online shop of developer tools.

MailBee.NET Objects fully supports:


  • HTTP
  • SSL/TLS (incl. TLS 1.3)
  • SASL
  • NTLM
  • Kerberos
  • SOCKS4/5
  • HTTP Proxy


  • DomainKeys/DKIM
  • S/MIME
  • FIPS 104-2
  • OAuth2


Servers & Services

  • MS Exchange
  • Lotus Notes
  • GroupWise
  • IMail
  • MailEnable
  • AxiGen
  • SmarterMail
  • SurgeMail
  • MDaemon
  • Kerio
  • CommuniGate
  • hMailServer
  • Exim
  • Postfix
  • Sendmail
  • Qmail
  • Courier
  • Dovecot
  • Cyrus
  • Zimbra

...and any POP3/SMTP/IMAP compliant servers

SMTP Object

  • Can send any MailMessage object as e-mail
  • Can send bulk mail and do mail merge over database
  • Can send to relay SMTP server or perform DNS MX lookup and send without relay server
  • Can send through a proxy server
  • Can sign messages with DomainKeys/DKIM signature
  • UNIQUE Supports backup SMTP/DNS servers and server farms for reliable and faster sending large volumes of e-mails
  • Send messages with a single line of code (QuickSend)
  • Async/await methods
  • Can submit messages to IIS SMTP and MailBee.NET Queue
  • Multi-threaded sending (up to 60 threads)
  • Supports secure TLS/SSL connections out-of-box (supports Gmail, etc)
  • PIPELINING for faster send
  • DSN (Delivery Status Notifications)
  • ESMTP authentication (LOGIN, PLAIN, CRAM-MD5, DIGEST-MD5, NTLM, Kerberos)
  • POP-before-SMTP authentication
  • UNIQUE Windows Integrated Authentication (authenticate using the current Windows user credentials)
  • User-defined authentication methods
  • Track accepted and refused recipients
  • Test send without actual sending for email address verification
  • Automatic detection and use of ESMTP extensions (EHLO)
  • Logging send-mail session into a file or memory
  • Send user-defined commands to the server
  • Can be placed on the form or created in the code

Smtp Object reference...

MailMessage Object

  • Import and export from/into System.Net.Mail.MailMessage
  • Used by Smtp object as outgoing e-mail
  • Returned by Pop3 and Imap objects as incoming e-mail
  • Multiple recipients (To/CC/BCC)
  • Multiple attachments
  • Advanced mail merge
  • Can be encrypted, signed, decrypted, or verified with Smime object
  • Easy access to plain-text and HTML body
  • Full support of international encodings and charsets
  • Can extract attachments from MS-TNEF (winmail.dat) files
  • Access to every MIME part
  • Access to all message headers
  • Access to message timestamps ("Received:" headers)
  • UNIQUE Conversion from HTML to plain-text and vice versa including high-lighting of URIs, images, quotations, etc
  • UNIQUE Full support of creating and displaying HTML messages with embedded pictures in desktop and web applications
  • UNIQUE Access forwarded messages (GetEncapsulatedMessage)
  • Forward message as attachment
  • Import HTML file or web page into e-mail
  • Import & export message data from/into memory, file and stream
  • Serialize into XML and deserialize from XML
  • Base64 and Quoted-Printable
  • Confirm Read & Confirm Receipt
  • Reply-To, Priority, Importance, Sensitivity, etc

MailMessage Object reference...

What's new

Version 12.4

  • Office 365 OAuth 2.0 Credentials Flow for SMTP
  • Improved MIME message builder
  • .NET 8.0 officially supported

See Version History for details

Version 12.3.1

  • Misc. TLS 1.2 and TLS 1.3 improvements.

Version 12.3

  • TLS 1.3 support.

Version 12.2

  • Office 365 OAuth 2.0 support (developer guides and samples available for desktop and ASP.NET Core apps).
  • ESMTP CRAM-MD5 authentication improved.
  • Documentation improvements.

Version 12.1

  • Separate UWP .NET Standard 2.0 edition for UWP apps targeting Windows 10 Fall Creators Update and newer. Has no Win32 dependencies and can be used in UWP Release builds published in Microsoft Store.
  • DNS MX query parser now supports large UDP responses (greater than 512 bytes).

Version 12.0

  • .NET Core 2.0 / .NET Standard 2.0 edition revised and improved, including better support of .NET Core 2.1 and 2.2.
  • .NET Standard 2.0 support in UWP. UWP apps targeting Windows 10 Fall Creators Update and newer can use the fully-functional .NET Standard 2.0 edition of MailBee.NET Objects.
  • .NET Core 2.0 sample projects and tutorials added (UWP, console and ASP.NET Core). They feature OAuth 2.0 authentication against Google ( and Microsoft (,, providers along with sending and receiving e-mail using these providers.
  • Improved support of TLS 1.2, now it's selected automatically if supported by the server.
  • The ability to automatically DKIM sign each outgoing mail message (MailMessage.SetDomainKeysSignOnSend property).

Clients Say:

"I've been looking at the MailBee.NET application and love it." Matt Yeager
"Thanks again for your help. I like your products..." Ron Hill
"By the way I love your software. Great work thank you." Dennis Drogemuller