[Yandex Cloud documentation](../../index.md) > [Tutorials](../index.md) > [Serverless technologies](index.md) > Sending emails in Yandex Cloud Postbox using the AWS SDK > .NET Core # Sending emails using the AWS SDK for .NET Core In this tutorial, you will learn how to send emails via Yandex Cloud Postbox using the [AWS SDK for .Net Core](https://docs.aws.amazon.com/sdk-for-net/v4/developer-guide/net-dg-sdk-features.html). To start sending emails: 1. [Get your cloud ready](#before-begin). 1. [Configure a directory for authentication data](#auth). 1. [Create and run the application](#app). 1. [Check the result](#check-result). If you no longer need the resources you created, [delete them](#clear-out). ## Get your cloud ready {#before-begin} Sign up for Yandex Cloud and create a [billing account](../../billing/concepts/billing-account.md): 1. Navigate to the [management console](https://console.yandex.cloud) and log in to Yandex Cloud or create a new account. 1. On the **[Yandex Cloud Billing](https://center.yandex.cloud/billing/accounts)** page, make sure you have a billing account linked and it has the `ACTIVE` or `TRIAL_ACTIVE` [status](../../billing/concepts/billing-account-statuses.md). If you do not have a billing account, [create one](../../billing/quickstart/index.md) and [link](../../billing/operations/pin-cloud.md) a cloud to it. If you have an active billing account, you can create or select a [folder](../../resource-manager/concepts/resources-hierarchy.md#folder) for your infrastructure on the [cloud page](https://console.yandex.cloud/cloud). [Learn more about clouds and folders here](../../resource-manager/concepts/resources-hierarchy.md). ### Required paid resources {#paid-resources} The infrastructure support costs include: * Fee for using Yandex Cloud Postbox (see [Yandex Cloud Postbox pricing](../../postbox/pricing.md)). * Fee for public DNS queries and [DNS zones](../../dns/concepts/dns-zone.md), if you are creating a resource record in Cloud DNS (see [Cloud DNS pricing](../../dns/pricing.md)). ### Set up resources {#infrastructure} 1. [Create](../../iam/operations/sa/create.md) a service account. 1. [Assign](../../iam/operations/sa/assign-role-for-sa.md) the `postbox.sender` [role](../../postbox/security/index.md#postbox-sender) to the service account. 1. [Create](../../iam/operations/authentication/manage-access-keys.md) a static access key for the service account. Save the ID and secret key. 1. Create an [address](../../postbox/operations/create-address.md). 1. [Pass](../../postbox/operations/check-domain.md) a domain ownership check. ## Configure a directory for authentication data {#auth} 1. Create a directory to store the authentication data in and navigate to it: For macOS and Linux: ```bash mkdir ~/.aws/ ``` For Windows: ```bash mkdir C:\Users\\.aws\ ``` 1. In the `.aws` directory, create a file named `credentials`, copy the credentials you got when [creating a static access key](#infrastructure), and paste them into it: ```text [default] aws_access_key_id = aws_secret_access_key = ``` 1. Create a file named `config` with the default region settings and copy the following information to it: ```text [default] region = ru-central1 endpoint_url = https://postbox.cloud.yandex.net ``` ### Using environment variables {#variables} By default, the AWS SDK uses authentication data from environment variables if they are set. These variables have priority over authentication data from the `.aws/credentials` file. The following environment variables are supported: * `AWS_ACCESS_KEY_ID`: Static key ID. * `AWS_SECRET_ACCESS_KEY`: Secret key. To set environment variables, depending on your operating system, follow these steps: {% list tabs group=operating_system %} - Linux/macOS In the terminal, run this command: ```bash export AWS_ACCESS_KEY_ID= export AWS_SECRET_ACCESS_KEY= ``` - Windows In PowerShell, run: ```powershell $Env:AWS_ACCESS_KEY_ID= $Env:AWS_SECRET_ACCESS_KEY= ``` {% endlist %} ## Create and run the application {#app} 1. Get the application code: {% list tabs %} - Repository 1. Clone the repository: ```bash git clone https://github.com/yandex-cloud-examples/yc-postbox-examples ``` 1. Navigate to the folder in the cloned `csharp/Postbox/Postbox/` repository. 1. In the `Program.cs` file, specify the following: * Recipient's email address in the `ToAddresses` field, e.g., `receiver@yourdomain.com`. You will need access to this email address for the next step. * Sender's email address in the `FromEmailAddress` field. The sender's email domain must match the one specified in the Yandex Cloud Postbox address you created when [getting started](#infrastructure). For example, if your verified domain is `yourdomain.com`, you can use addresses like `noreply@yourdomain.com` or `admin@yourdomain.com` but not `user@mail.yourdomain.com`. - Manually 1. Create a directory named `postbox-csharp` and open it. 1. Create a file named `Program.cs` and paste this code into it: ```csharp using Amazon.Runtime; using Amazon.SimpleEmailV2; using Amazon.SimpleEmailV2.Model; var client = new AmazonSimpleEmailServiceV2Client( new AmazonSimpleEmailServiceV2Config { ServiceURL = "https://postbox.cloud.yandex.net", SignatureMethod = SigningAlgorithm.HmacSHA256, SignatureVersion = "4", AuthenticationRegion = "ru-central1", } ); try { var response = await client.SendEmailAsync( new SendEmailRequest { Destination = new Destination { ToAddresses = [""] }, Content = new EmailContent { Simple = new Message { Body = new Body { Text = new Content { Charset = "UTF-8", Data = "Hello, world!" } }, Subject = new Content { Charset = "UTF-8", Data = "Test email" } } }, FromEmailAddress = "" }); Console.Write(response.MessageId); } catch (Exception ex) { // Logging exceptions in JSON format Console.WriteLine(ex); } ``` 1. In the `Program.cs` file, specify the following: * Recipient's email address in the `ToAddresses` field, e.g., `receiver@yourdomain.com`. You will need access to this email address for the next step. * Sender's email address in the `FromEmailAddress` field. The sender's email domain must match the one specified in the Yandex Cloud Postbox address you created when [getting started](#infrastructure). For example, if your verified domain is `yourdomain.com`, you can use addresses like `noreply@yourdomain.com` or `admin@yourdomain.com` but not `user@mail.yourdomain.com`. 1. Create a file named `Postbox.csproj` and paste this code into it: ```xml Exe net8.0 enable enable ``` 1. Create a file named `Postbox.sln` and paste this code into it: ```text Microsoft Visual Studio Solution File, Format Version 12.00 Project("{FAE04EC0-301F-11D3-BF4B-00C04F79EFBC}") = "Postbox", "Postbox\Postbox.csproj", "{51272D55-8BA2-4072-9445-889E627E605D}" EndProject Global GlobalSection(SolutionConfigurationPlatforms) = preSolution Debug|Any CPU = Debug|Any CPU Release|Any CPU = Release|Any CPU EndGlobalSection GlobalSection(ProjectConfigurationPlatforms) = postSolution {51272D55-8BA2-4072-9445-889E627E605D}.Debug|Any CPU.ActiveCfg = Debug|Any CPU {51272D55-8BA2-4072-9445-889E627E605D}.Debug|Any CPU.Build.0 = Debug|Any CPU {51272D55-8BA2-4072-9445-889E627E605D}.Release|Any CPU.ActiveCfg = Release|Any CPU {51272D55-8BA2-4072-9445-889E627E605D}.Release|Any CPU.Build.0 = Release|Any CPU EndGlobalSection EndGlobal ``` {% endlist %} 1. Run the application: ```bash dotnet run ``` Result: ```text DB42OLB6KLNJ.7VDE********@ingress2-klg ``` ## Check the result {#check-result} Make sure the recipient specified in the file named `Program.cs` in the `ToAddresses` field has received an email with the specified parameters. ## How to delete the resources you created {#clear-out} To stop paying for the resources you created: 1. Delete the [address](../../postbox/concepts/glossary.md#adress). 1. [Delete](../../dns/operations/zone-delete.md) the DNS zone if you created a resource record in it.