Set up DMARC and see who's sending email using your brand's domain.

Send emails with .NET

Send emails from your .NET apps through Postmark API on time, every time.

5 Minute Set Up


Install the Postmark.NET library from NuGet

PM> Install-Package Postmark

Send an email asynchronously

// Import:
using PostmarkDotNet;

// Send an email asynchronously:
var message = new PostmarkMessage()
  To = "",
  From = "",
  TrackOpens = true,
  Subject = "A complex email",
  TextBody = "Plain Text Body",
  HtmlBody = "HTML goes here",
  Tag = "New Year's Email Campaign",
  Headers = new HeaderCollection{
    {"X-CUSTOM-HEADER", "Header content"}

var client = new PostmarkClient("POSTMARK-SERVER-API-TOKEN-HERE");
var sendResult = await client.SendMessageAsync(message);

if (sendResult.Status == PostmarkStatus.Success){ /* Handle success */ }
else { /* Resolve issue.*/ }

Want to test our APIs and activity logging? Send emails to


Once you’ve sent your first email, check out the .NET library docs →

Check out what some of our customers have said

We were using one of your competitors because they featured a freemium plan. However we were getting complaints on a weekly basis that emails weren’t reaching clients. […] Other than an edge case here or there, since switching to Postmark, our support tickets regarding email delivery have plummeted to zero. That alone makes Postmark worth its weight in gold.

Kyle Racki

Kyle Racki

CEO at Proposify

We‘ve grown from sending 0 to 200,000 transactional emails daily, and Postmark helped us a lot with scaling that process.

Bartosz Olchówka

Bartosz Olchówka

Head of Development at LiveChat

I’ve used SendGrid, Mandrill and Postmark for transactional email in production. Amazing how much better Postmark is than everyone else.

Andreas Zecher

Andreas Zecher

Founder and Developer at Promoter

We use Postmark and are very happy with it. Switched from SendGrid due to security problems, dodgy UI, and not storing email content.

Jonny Paylor

Jonny Paylor

via Twitter

From side projects to Fortune 500...

We’ve got you covered. We process transactional email for companies of all sizes:

Everything you need for first class email delivery

A comprehensive suite of tools to help you seamlessly integrate email with your .NET application.

  • Placeholder

    We’re focused on building the best reputation in the industry for transactional email.

  • One credit equals one email.

    Simple and transparent pricing means you only pay for what you use.

  • Placeholder

    Responsive templates for sending transactional emails, including welcome messages, password resets, and more.

  • Placeholder

    Increased visibility with detailed open and delivery tracking for every email.

  • Placeholder

    Easy integration via API or SMTP so you can start sending in minutes.

  • Envelope flying into postbox.

    Industry-leading delivery speeds. Up to 4x faster than other providers.

Lightning fast delivery

Your customers expect transactional emails to arrive immediately—not eventually.
We constantly monitor our delivery speeds and share the data publicly.

  • Gmail

  • Apple

  • Hotmail

  • AOL

  • Yahoo

Time to Inbox data updated every 5 minutes

Ready to get started?

Join thousands of developers that already trust their email delivery to Postmark.