---
title: "Configuration"
manual: "Microsoft Exchange 365 Mailer"
version: "3.2"
permalink: "https://docs.typo3.org/permalink/oliverkroener/ok-exchange365-mailer:configuration@3.2"
source: "Configuration/Index.rst"
rendered: "2026-10-04T19:57:30+00:00"
---

# Configuration {#configuration}

This section covers all aspects of configuring the Microsoft Exchange 365 Mailer extension for TYPO3.

After completing the [Azure Configuration](https://docs.typo3.org/permalink/oliverkroener/ok-exchange365-mailer:azure@3.2), you need to configure the TYPO3 extension with the values obtained from Microsoft Entra ID.

-   [Essential](https://docs.typo3.org/permalink/oliverkroener/ok-exchange365-mailer:essential-configuration@3.2)
-   [Frontend](https://docs.typo3.org/permalink/oliverkroener/ok-exchange365-mailer:frontend-configuration@3.2)

## Quick Configuration Overview {#quick-configuration-overview}

The extension requires the following key configuration variables:

1.  **Mail Transport**: Set to use Exchange365Transport
1.  **Tenant ID**: Your Microsoft Entra ID tenant identifier
1.  **Client ID**: Your Azure application identifier
1.  **Client Secret**: Your Azure application secret
1.  **From Email**: The sender email address
1.  **Graph Sender User ID** (optional): Graph mailbox for *Send As* / *Send On Behalf*
1.  **Save to Sent Items** (optional): Whether to save emails to sent folder

For detailed step-by-step instructions, see:

-   [Essential Configuration](https://docs.typo3.org/permalink/oliverkroener/ok-exchange365-mailer:essential@3.2) \- For server-side email sending (recommended for production)
-   [Frontend Configuration](https://docs.typo3.org/permalink/oliverkroener/ok-exchange365-mailer:frontend@3.2) \- Optional per-site TypoScript overrides for frontend mail (Powermail, Form Framework)

## Configuration Methods {#configuration-methods}

The transport is selected only in `$GLOBALS['TYPO3_CONF_VARS']['MAIL']['transport']`.
The credentials and sender can come from:

-   ****Essential Configuration** (baseline for every context)**

    -   Environment variables, mapped onto `TYPO3_CONF_VARS` by your project
    -   `AdditionalConfiguration.php` reading the environment

-   ****Frontend Configuration** (optional per-site overrides)**

    -   TypoScript, ideally with `:= getEnv(...)`. Non-empty TypoScript values
        override `TYPO3_CONF_VARS` per setting; empty values fall back.

If `TYPO3_CONF_VARS` is configured, frontend forms (Powermail, Form Framework)
work without any TypoScript.

> [!WARNING]
> **Attention**
>
> **Security Recommendation**: Never write the client secret as a literal value
> into TypoScript or configuration files. Read it from the environment.