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

# SMTP Overlay

> Use SendyKit’s outbound transport layer to operate beyond Sendy’s SES-only default

## Why it exists

Sendy is historically centered on Amazon SES. SendyKit adds an outbound transport layer so operators can run with broader provider support while preserving Sendy compatibility.

## What it covers

SendyKit’s transport layer is where you manage:

* provider-backed outbound delivery settings
* operational transport checks
* replay and delivery workflows
* billing-aware machine-paid transport actions when enabled

## Operator outcome

This lets you keep the familiar Sendy data model while moving transport operations into a more flexible control plane.

## Related guides

* [Configuration](/configuration)
* [Quickstart](/quickstart)
* [API Introduction](/api-reference/introduction)