How to send HTML message via Mimekit/Mailkit

Solution 1:

Using a BodyBuilder like you are doing is probably the easiest way.

var bodyBuilder = new BodyBuilder();
bodyBuilder.HtmlBody = "<b>This is some html text</b>";
bodyBuilder.TextBody = "This is some plain text";

message.Body = bodyBuilder.ToMessageBody();

client.Send(message);

Solution 2:

MimeKit Documentation - Creating Messages

var message = new MimeMessage();    
message.Body = new TextPart ("html") { Text = "<b>Test Message</b>" };

"A TextPart is a leaf-node MIME part with a text media-type. The first argument to the TextPart constructor specifies the media-subtype: plain, html, enriched, rtf, and xml."

Solution 3:

One other option here if you want to be strict;

msg.Body = new TextPart(MimeKit.Text.TextFormat.Html) { Text = "<b>html content</b>" };

Solution 4:

var bodyBuilder = new BodyBuilder();
bodyBuilder.HtmlBody = body;
bodyBuilder.TextBody = "-";

message.Body = bodyBuilder.ToMessageBody();

In some mail ISP, you should always set bodyBuilder.TextBody by value.