Configure mail on TurboStack

Set up outbound mail on TurboStack - DKIM domain signing and the development mail-catcher - from the host's Advanced > Mail Settings, with the YAML keys it writes.

Outbound mail is a host-level service. You configure two things: DKIM signing for your sending domains, and an optional development mail-catcher. Both live under the host's Advanced > Mail Settings. For the background on how mail works, see What is mail on TurboStack?.

Mail Settings on the host's Advanced tab
Mail Settings on the host's Advanced tab

Where to configure it

Open the host, go to the Advanced tab, and select Mail Settings. Changes are written to the host's YAML and applied on the next deployment.

Set up DKIM

DomainKeys Identified Mail (DKIM) signs your outbound mail so receiving servers can confirm it genuinely came from your domain. In Mail Settings, add one DKIM entry per sending domain:

  1. Enter the FQDN - the Fully Qualified Domain Name you send mail from (for example example.com).

  2. Enter a selector - this becomes the subdomain part of the DKIM DNS record. If you leave it empty, TurboStack uses the default selector cloud.

  3. Save the entry and deploy.

  4. Connect over SSH and run tscli dkim records to get the DKIM TXT record to publish.

  5. Add that record as a TXT record in your domain's Domain Name System (DNS) - in the Customer Center DNS management if Hosted Power manages your DNS, otherwise at your DNS provider.

  6. Back on the server, run tscli dkim validate to confirm the record was created correctly.

You can add multiple DKIM entries if you send from more than one domain. For Sender Policy Framework (SPF) and Domain-based Message Authentication, Reporting and Conformance (DMARC), which are DNS-only and not set here, see Mail deliverability.

Development mail-catcher

A mail-catcher captures outbound mail so you can inspect it in a web interface instead of delivering it - useful while building or testing an application. Enable it under Mail Settings with the Enable mail capturing and mail testing option, then choose which tool to run:

  • Mailpit - the recommended catcher.
  • Mailhog - the older catcher; no longer maintained.

Once enabled, PHP mail is intercepted automatically (via php.ini) by default, so mail your application sends is captured without any code change. You can turn off auto-interception if you only want the catcher available for applications that target it directly.

YAML configuration

These are the keys the Mail Settings form writes to the host YAML.

DKIM

DKIM is configured as a dkim object with a keys list. Each entry sets the fqdn and, optionally, the selector (defaults to cloud).

dkim:
  keys:
    - fqdn: example.com
      selector: cloud
    - fqdn: shop.example.com
      selector: cloud

Development mail-catcher

Key Meaning
mail_devtool Which catcher to install: mailpit or mailhog. This is the key that switches the catcher on - set it and the matching catcher is installed, leave it out and neither is installed (an existing one is removed). No other value is accepted.
mailhog_install The Enable mail capturing and mail testing toggle in Mail Settings. It controls whether the catcher choice is shown in the form and is not read during deployment, so on its own it installs nothing.
mail_auto_intercept Whether PHP mail is auto-intercepted through php.ini. Defaults to true, so interception is on; set it to false to leave PHP alone and catch only the mail that applications send to the catcher directly. 
# Installs Mailpit as the mail-catcher:
mail_devtool: mailpit
# Optional - auto-interception is on by default; set it to false to turn it off:
mail_auto_intercept: false

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