> ## Documentation Index
> Fetch the complete documentation index at: https://docs.apollodeploy.com/llms.txt
> Use this file to discover all available pages before exploring further.

# Send emails with .NET

> Send a transactional email with the official Apollo Signal .NET SDK

The .NET 8 SDK provides an async class-based client and uses
`https://api.signal.apollodeploy.com` by default.

Before you start, [create an API key](/signal/create-an-api-key) with **Emails: Send** permission
and [verify the From domain](/signal/add-a-domain).

<Steps>
  <Step title="Install the SDK">
    ```bash theme={"dark"}
    dotnet add package ApolloDeploy.Signal
    ```
  </Step>

  <Step title="Store your API key">
    Set `SIGNAL_API_KEY` in the server environment or secret manager.
  </Step>

  <Step title="Send an email">
    ```csharp theme={"dark"}
    using System;
    using System.Collections.Generic;
    using ApolloDeploySignal;

    using var signal = new ApolloSignalApiClient(new ApolloSignalApiClientConfig
    {
        DefaultHeaders = new()
        {
            ["Authorization"] = $"Bearer {Environment.GetEnvironmentVariable("SIGNAL_API_KEY")}",
        },
    });

    var email = await signal.Emails.SendEmailAsync(new SendEmailRequest
    {
        From = "auth@mail.company.com",
        To = new List<string> { "alex@example.com" },
        Subject = "Reset your password",
        Text = "Use the secure link in your account to choose a new password.",
    });

    Console.WriteLine(email.Id);
    ```
  </Step>
</Steps>

<Note>
  Reuse the client or inject a shared `HttpClient` through its configuration in long-running
  applications. Dispose the SDK client when the application shuts down.
</Note>

<CardGroup cols={2}>
  <Card title="All SDKs" icon="code" href="/signal/send-with/sdk-overview">
    Compare every supported language and framework.
  </Card>

  <Card title="Manage emails" icon="envelope" href="/signal/dashboard/emails/introduction">
    Follow message states and delivery timelines.
  </Card>
</CardGroup>