# SMTP

## Description

SMTP is the simplest way to send transactional email through any standards-compliant mail server (Office365, Gmail with app password, on-prem SMTP, etc.).

Your application code depends on `IFlexEmailProvider`; the SMTP provider supplies that implementation.

## Configuration in DI

Register only the provider.

```csharp
services.AddFlexSmtpEmailProvider(configuration);
```

## appsettings.json

Configuration is read from `FlexBase:Providers:Email:Smtp`.

```json
{
  "FlexBase": {
    "Providers": {
      "Email": {
        "Smtp": {
          "Host": "smtp.office365.com",
          "Port": 587,
          "UseSsl": true,
          "UseStartTls": true,
          "Username": "user@company.com",
          "Password": "<store-in-secrets>",
          "DefaultFromEmail": "noreply@company.com",
          "DefaultFromName": "Company",
          "MaxRetries": 3,
          "Timeout": "00:00:30"
        }
      }
    }
  }
}
```

## Examples (template-based)

This mirrors the generated PostBus handler shape (you do not register the handler manually).

```csharp
using Microsoft.Extensions.Logging;
using Sumeru.Flex;
using System.Threading.Tasks;

namespace {YourApplication}.PostBusHandlers.Email;

public partial class SendSmtpEmailHandler : ISendSmtpEmailHandler
{
	protected string EventCondition = string.Empty;

	protected readonly ILogger<SendSmtpEmailHandler> _logger;
	protected readonly IFlexHost _flexHost;
	protected readonly IFlexEmailProvider _emailProvider;

	protected FlexAppContextBridge? _flexAppContext;

	public SendSmtpEmailHandler(
		ILogger<SendSmtpEmailHandler> logger,
		IFlexHost flexHost,
		IFlexEmailProvider emailProvider)
	{
		_logger = logger;
		_flexHost = flexHost;
		_emailProvider = emailProvider;
	}

	public virtual async Task Execute(SendSmtpEmailCommand cmd, IFlexServiceBusContext serviceBusContext)
	{
		_flexAppContext = cmd.Dto.GetAppContext();  //do not remove this line

		await _emailProvider.SendHtmlAsync(
			to: cmd.Dto.To,
			subject: cmd.Dto.Subject,
			htmlBody: cmd.Dto.Html,
			from: cmd.Dto.From);

		await this.Fire(EventCondition, serviceBusContext);
	}
}
```

## Provider considerations

* Prefer StartTLS on port 587 for most providers.
* Use secrets storage for `Password`.


---

# Agent Instructions: Querying This Documentation

If you need additional information that is not directly available in this page, you can query the documentation dynamically by asking a question.

Perform an HTTP GET request on the current page URL with the `ask` query parameter:

```
GET https://docs.flexbase.in/data-and-providers/providers/e-mail/smtp.md?ask=<question>
```

The question should be specific, self-contained, and written in natural language.
The response will contain a direct answer to the question and relevant excerpts and sources from the documentation.

Use this mechanism when the answer is not explicitly present in the current page, you need clarification or additional context, or you want to retrieve related documentation sections.