Configuration

Courier's config file lives at app/Config/Courier.php after you publish it. Every option has a default that works out of the box — you only need to set what you want to change.

Options

$fromName / $fromEmail

<?php
public string $fromName  = 'Acme Newsletter';
public string $fromEmail = 'hello@acme.com';

The default sender name and address for all outgoing emails. Individual campaigns can override these — these values are the fallback when a campaign doesn't specify its own.

$defaultLayout

<?php
public string $defaultLayout = 'Myth\Courier\Views\courier/layouts/default';

The email layout view used when a campaign doesn't have one set. Courier ships with a simple responsive layout at Views/courier/layouts/default.php. Point this at your own view to apply a custom look site-wide.

See Email Templates for how layouts work.

$trackingHost

<?php
public string $trackingHost = '';

The base URL used to build tracking pixel URLs, click redirect URLs, and unsubscribe links. Leave empty and Courier will use CI4's base_url() automatically. Set it if you're using a custom tracking domain:

<?php
public string $trackingHost = 'https://track.acme.com';

$batchSize

<?php
public int $batchSize = 200;

How many emails to send per courier:send-campaign or courier:process-drips command run. If a campaign has 10,000 contacts, the command works through them in chunks of 200 across successive cron runs.

Lower this if you're hitting rate limits; raise it if your email provider supports higher throughput.

$throttleMs

<?php
public int $throttleMs = 0;

Milliseconds to sleep between individual sends within a batch. 0 means no delay. Set this if your email provider has a per-second sending limit:

<?php
public int $throttleMs = 100; // ~10 emails/second max

$markdownPath

public string $markdownPath = '';

The base directory Courier uses when resolving markdown email files. Leave empty and it defaults to APPPATH (your app's app/ folder). Set an absolute path to load markdown files from a different location:

public string $markdownPath = APPPATH . 'Emails/';

With this set, a campaign view of welcome.md resolves to app/Emails/welcome.md.

See Email Templates for the full markdown workflow.

$testMode

<?php
public bool $testMode = false;

When true, Courier skips the actual mailer and logs what it would send instead. Use this in development or CI to verify your campaign setup without delivering real emails:

<?php
public bool $testMode = true;

You'll see log entries like:

[Courier] testMode: would send to ada@example.com subject "Welcome to Acme"

Environment-specific config

You can override any config value per-environment using CI4's .env file:

courier.testMode = true
courier.batchSize = 50