Sending Configuration (SMTP)

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SMTP Connectors

Go to SMTP in the sidebar to see your connectors list. This is where you add and manage individual SMTP server connections.

The Connectors Table

Each connector shows:

Adding a New Connector

Click Add Connector and fill in the form:

1. Connector Name -- A friendly label (e.g., “Primary Mailgun” or “Transactional SES”).
2. Host -- Your SMTP server hostname (e.g., smtp.mailgun.org).
3. Port -- Usually 587 for STARTTLS or 465 for TLS.
4. Encryption -- Choose None, TLS, or STARTTLS. Most modern providers use STARTTLS on port 587.
5. Username -- Your SMTP username (often your email address or an API key).
6. Password -- Your SMTP password or API secret.
7. Max Parallel Connections -- How many simultaneous connections to open (1-100, default is 5). Higher numbers send faster but may hit provider limits.
8. Max Messages / Hour -- The hourly sending limit for this connector (1 to 1,000,000, default is 10,000). Set this to match your provider's rate limit.
9. Is Active -- Toggle this on to make the connector available for sending.

Testing Your Connection

Before you start sending real emails, click Test Connection on the connector form. Punchmail will attempt to connect to the SMTP server using your settings and report back with a pass or fail result, along with a timestamp.

This is a quick way to verify that your host, port, encryption, username, and password are all correct.

Editing and Managing Connectors

• Click Edit on any connector row to update its settings. When editing, you can leave the password field blank to keep the current password.
• Click the Toggle button to activate or deactivate a connector without deleting it.
• Click Delete to permanently remove a connector.

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SMTP Pools

Pools let you group multiple SMTP connectors together and distribute your sending load across them. This is useful for high-volume sending or when you want redundancy.

Navigate to the pools page by clicking View Pools on the connectors page, or go to SMTP > Pools directly.

How Pools Work

A pool contains two or more connectors, each with a weight (a percentage). When Punchmail sends an email through a pool, it distributes messages across the connectors based on their weights.

For example, if you have: - Connector A at 70% - Connector B at 30%

Then roughly 70% of emails will go through Connector A and 30% through Connector B.

Creating a Pool

Click Create Pool (or the plus button on the pools page) and fill in:

1. Pool Name -- A descriptive label (e.g., “High Volume Sending Pool”).
2. Is Active -- Toggle on to make the pool available for use.
3. Add Connectors -- Click “Add Connector” to add a row, then:
4. Select a connector from the dropdown
5. Set its weight (0-100%)
6. Repeat for each connector you want in the pool

Weight Distribution

The weight visualization bar gives you a visual breakdown of how your sending load is distributed. The weights must add up to exactly 100%.

If your weights don't sum to 100%, you'll see a warning with the current total. Click the Auto-normalize button to automatically redistribute the weights evenly.

You can remove a connector from the pool by clicking the X button next to it.

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Global SMTP Settings

Go to Settings in the sidebar, then click the SMTP tab. Here you'll find platform-wide sending configuration:

Quick Links

At the top, you'll see quick links to jump to the Manage Connectors and Manage Pools pages.

Defaults

• Default Connector -- Choose which SMTP connector to use when a campaign or automation doesn't specify one.
• Default Pool -- Choose a default pool instead of (or in addition to) a default connector.

Global Throttle Settings

These settings apply platform-wide, regardless of which connector or pool is being used:

These global throttles work alongside the per-connector limits. The most restrictive limit always wins.

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How SMTP Selection Works in Campaigns

When creating a campaign, in Step 2 (Sending), you'll see:

• SMTP Server -- A dropdown listing all your active connectors and pools. Connectors are grouped under “Connectors” and pools under “Pools.”
• Fallback SMTP -- An optional backup. If the primary connector fails, Punchmail will try the fallback.

If you don't select anything, the platform default (configured in Settings > SMTP) will be used.

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How SMTP Selection Works in Automations

Automations have two levels of SMTP override:

1. Automation-level -- In the workflow designer's top bar, you can select an SMTP connector that applies to all Send Email nodes in that automation.
2. Per-node override -- Each individual Send Email node can override the automation-level setting with its own SMTP connector.

The priority order is: Send Email node override > Automation-level override > Platform default.

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Tips

• Match your rate limits -- Set the Max Messages/Hour on each connector to match what your SMTP provider allows. Going over their limit will cause bounces or temporary blocks.
• Use pools for redundancy -- If one provider goes down, the others in the pool keep sending.
• Test before sending -- Always use the Test Connection button after setting up a new connector. A typo in the hostname or password is easy to catch with a quick test.
• Start conservative -- If you're not sure about your provider's limits, start with lower Max Parallel Connections (2-3) and Max Messages/Hour, then increase gradually.
• Use fallback connectors -- For important campaigns, set a fallback SMTP so your emails still go out even if the primary server has issues.