How to Send Email in C# / .NET (SMTP & API)

Here is how to send email in C# / .NET so it actually reaches the inbox.

Your options in C# / .NET

MailKit is the modern choice for SMTP; call an API with HttpClient for scale. (System.Net.Mail (SmtpClient) or MailKit for SMTP, or HttpClient for an API.)

Make it land, not bounce

• Authenticate your domain with SPF, DKIM and DMARC.
• Send from a dedicated, warmed IP.
• Handle bounces and complaints via webhooks.

How Rainmail helps

Rainmail sends from your own domain on a dedicated, isolated IP with SPF, DKIM, DMARC, reverse-DNS and managed warm-up handled for you, plus a REST API and an AI watching deliverability — and it welcomes senders SES, SendGrid and Mailchimp reject, from $8. Run the free checker or see plans.