MailBee.NET SMTP enables .NET applications to compose, mail merge, send mail to SMTP server (including Gmail and MS Exchange), submit to IIS SMTP or MailBee Message Queue, or send directly via DNS MX lookup.

Written in 100% managed C# code. Can be used in desktop, console, mobile and ASP.NET applications developed in C#, VB.NET and other .NET languages. Supports .NET 2.0/3.0/3.5/4.0/4.5+ (Client Profile compatible), .NET Core 1.0/1.1, Xamarin (Android/iOS), UWP (Universal Windows).

The key features:

mail merge over database, send a web page, read/delivery receipt, DSN;
send to MailBee.NET Queue or IIS SMTP queue;
direct send via DNX MX lookup;
make DNS MX, PTR or TXT query;
SMTP PIPELINING and other ESMTP extensions;
secure TLS/SSL connections, up to TLS 1.2;
OAuth 2.0;
proxy connections (SOCKS4/SOCKS5/HTTP);
S/MIME mail and certificates;
create DomainKeys/DKIM signature to pass through spam filters;
secure and user-defined ESMTP authentication (including NTLM, GSSAPI and POP-before-SMTP);
Windows Integrated Authentication (log in as the current Windows user);
accurate and flexible MIME builder;
compose HTML mails with embedded pictures;
HTML-to-PlainText conversion and vice versa, alternative body generation;
powerful HTML parser and processor;
international charsets, UTF-8, TO/CC/BCC, custom headers, custom message formats (e.g. meeting request items);
email address parsing and validation;
international e-mail addresses (IDN domains)
multiple attachments, file and memory attachments;
XML and System.Net.Mail.MailMessage import/export, streams, backup SMTP and DNS servers, multi-threading, async/await methods;
track accepted and refused recipients;
forward/resend mails loaded from a file or received with other components (such as MailBee.NET POP3);
events and error handling features, memory/file logging, debug functions, etc.

Samples: C# and VB.NET, WinForms and ASP.NET, .NET 2.0+ and .NET 4.5+.

Royalty-free distribution allowed.