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Devilbox

Enable and configure MailHog

Enable and configure MailHog

MailHog catches outgoing application email during development and shows it in a browser UI, avoiding accidental delivery to real recipients.

How it works

Devilbox keeps optional integrations as override snippets in the compose/ directory. To enable MailHog, copy its snippet into the project root as docker-compose.override.yml, then start the stack.

Enable

Terminal window
cp compose/docker-compose.override.yml-mailhog docker-compose.override.yml
./dvl.sh up

Configuration

The snippet defines service mailhog with image ${MAILHOG_IMAGE:-mailhog/mailhog}:${MAILHOG_SERVER:-latest}, hostname mailhog, IP 172.16.238.252, and UI port ${HOST_PORT_MAILHOG:-8025}:8025. It does not mount volumes.

VariableDefaultPurpose
MAILHOG_IMAGEmailhog/mailhogMailHog image repository.
MAILHOG_SERVERlatestMailHog image tag.
HOST_PORT_MAILHOG8025Host port for the MailHog Web UI.

Configure PHP to send mail to MailHog’s SMTP listener:

[mail function]
sendmail_path = '/usr/local/bin/mhsendmail --smtp-addr="mailhog:1025"'

Place that in the php.ini directory for your selected PHP version, for example cfg/php-ini-8.3/mailhog.ini.

Usage

Open the mailbox UI:

Terminal window
open http://localhost:8025

Send a test email from inside PHP:

Terminal window
./dvl.sh exec php -r 'mail("[email protected]", "Devilbox test", "Hello from MailHog");'

Point an application SMTP client at host mailhog, port 1025, without TLS or authentication.

Disable

Terminal window
./dvl.sh down
rm docker-compose.override.yml
./dvl.sh up

Remove the MailHog php.ini file if PHP should return to its previous mail transport.

Troubleshooting

  • If messages do not appear, confirm PHP is using the php.ini file for the active PHP version.
  • If the UI does not load, check whether another process already uses host port 8025 and adjust HOST_PORT_MAILHOG.
  • If an app uses SMTP directly, verify it points to mailhog:1025 from inside the Docker network, not localhost.

See also