Send Email from the Command Line with Swaks

Send emails through AhaSend’s SMTP servers directly from your terminal using Swaks, a powerful command-line tool designed for testing and debugging SMTP servers. Perfect for scripting, automation, and troubleshooting email delivery issues.

What is Swaks? Swaks (Swiss Army Knife for SMTP) is a versatile, scriptable tool for testing SMTP servers and sending emails from the command line. It supports TLS encryption, various authentication methods, and is designed as a diagnostic tool rather than for high-volume sending.

Prerequisites

Before sending, verify your domain and create an SMTP credential. Use a sandbox credential for these examples so no email is delivered. Keep the username and password in your server’s secret store. Before you begin, ensure you have:

System Requirements

Swaks installed on your system
Command line access (Terminal, Command Prompt, etc.)
Basic familiarity with command-line tools

Installation

Install Swaks using your system’s package manager:

sudo apt-get update
sudo apt-get install swaks

# CentOS/RHEL
sudo dnf install epel-release
sudo dnf install swaks

# Fedora
sudo dnf install swaks

brew install swaks

wsl --install
# In the Ubuntu WSL shell, follow the Ubuntu/Debian instructions above.

Connection Settings

Setting	Value
Host	`send.ahasend.com`
Ports with STARTTLS	25, 587 and 2525
Port with implicit TLS	465 (TLS from the first byte, also called SSL/TLS or SMTPS)
Encryption	Required on every port: STARTTLS on 25, 587 and 2525, implicit TLS on 465
Authentication	AUTH PLAIN after STARTTLS on 25, 587 and 2525; AUTH PLAIN or AUTH LOGIN on 465
Username and password	Your SMTP credential, not an API key

All message data is stored in the EU. See SMTP limits.

Basic Email Examples

swaks \
  --from hello@yourdomain.com \
  --to user@example.com \
  --server send.ahasend.com \
  --port 587 \
  --auth plain \
  --tls \
  --auth-user 'YOUR_SMTP_USERNAME' \
  --auth-password 'YOUR_SMTP_PASSWORD' \
  --header 'Subject: Welcome to our platform!' \
  --body "Thanks for signing up. We're excited to have you!"

swaks \
  --from hello@yourdomain.com \
  --to user@example.com \
  --server send.ahasend.com \
  --port 587 \
  --auth plain \
  --tls \
  --auth-user 'YOUR_SMTP_USERNAME' \
  --auth-password 'YOUR_SMTP_PASSWORD' \
  --header 'Subject: Welcome to our platform!' \
  --body "<html><body><h1>Welcome!</h1><p>Thanks for signing up. We're <strong>excited</strong> to have you!</p></body></html>" \
  --add-header "Content-Type: text/html"

swaks \
  --from hello@yourdomain.com \
  --to user@example.com \
  --server send.ahasend.com \
  --port 587 \
  --auth plain \
  --tls \
  --auth-user 'YOUR_SMTP_USERNAME' \
  --auth-password 'YOUR_SMTP_PASSWORD' \
  --header 'Subject: Your Invoice is Ready' \
  --body "Please find your invoice attached to this email." \
  --attach @/path/to/invoice.pdf

swaks \
  --from hello@yourdomain.com \
  --to user@example.com \
  --server send.ahasend.com \
  --port 465 \
  --auth login \
  --tls-on-connect \
  --auth-user 'YOUR_SMTP_USERNAME' \
  --auth-password 'YOUR_SMTP_PASSWORD' \
  --header 'Subject: Welcome to our platform!' \
  --body "Thanks for signing up. We're excited to have you!"

On port 465, use --tls-on-connect instead of --tls. Port 465 accepts --auth login and --auth plain.

Advanced Examples

swaks \
  --from hello@yourdomain.com \
  --to user1@example.com,user2@example.com \
  --server send.ahasend.com \
  --port 587 \
  --auth plain \
  --tls \
  --auth-user 'YOUR_SMTP_USERNAME' \
  --auth-password 'YOUR_SMTP_PASSWORD' \
  --header 'Subject: Newsletter Update' \
  --body "This is our latest newsletter update."

swaks \
  --from hello@yourdomain.com \
  --to user@example.com \
  --cc manager@yourdomain.com \
  --bcc analytics@yourdomain.com \
  --server send.ahasend.com \
  --port 587 \
  --auth plain \
  --tls \
  --auth-user 'YOUR_SMTP_USERNAME' \
  --auth-password 'YOUR_SMTP_PASSWORD' \
  --header 'Subject: Project Update' \
  --body "Here's the latest project update."

swaks \
  --from hello@yourdomain.com \
  --to user@example.com \
  --server send.ahasend.com \
  --port 587 \
  --auth plain \
  --tls \
  --auth-user 'YOUR_SMTP_USERNAME' \
  --auth-password 'YOUR_SMTP_PASSWORD' \
  --header 'Subject: Documents Package' \
  --body "Please find the requested documents attached." \
  --attach @/path/to/document1.pdf \
  --attach @/path/to/document2.xlsx

Using Special Headers

Add AhaSend’s special headers to control tracking, retention, and other features:

swaks \
  --from hello@yourdomain.com \
  --to user@example.com \
  --server send.ahasend.com \
  --port 587 \
  --auth plain \
  --tls \
  --auth-user 'YOUR_SMTP_USERNAME' \
  --auth-password 'YOUR_SMTP_PASSWORD' \
  --header 'Subject: Newsletter with Tracking' \
  --add-header "ahasend-track-opens: true" \
  --add-header "ahasend-track-clicks: true" \
  --add-header "ahasend-tags: newsletter,cli,swaks" \
  --body "<html><body><h1>Newsletter</h1><p>Check out our <a href='https://yourdomain.com/features'>latest features</a>!</p></body></html>" \
  --add-header "Content-Type: text/html"

swaks \
  --from hello@yourdomain.com \
  --to user@example.com \
  --server send.ahasend.com \
  --port 587 \
  --auth plain \
  --tls \
  --auth-user 'YOUR_SMTP_USERNAME' \
  --auth-password 'YOUR_SMTP_PASSWORD' \
  --header 'Subject: Temporary Notification' \
  --add-header "AhaSend-Metadata-Retention: 7" \
  --add-header "AhaSend-Data-Retention: 1" \
  --body "This is a temporary notification that will be automatically deleted."

swaks \
  --from hello@yourdomain.com \
  --to user@example.com \
  --server send.ahasend.com \
  --port 587 \
  --auth plain \
  --tls \
  --auth-user 'YOUR_SMTP_USERNAME' \
  --auth-password 'YOUR_SMTP_PASSWORD' \
  --header 'Subject: Product Update with Tracking' \
  --add-header "ahasend-track-opens: true" \
  --add-header "ahasend-track-clicks: true" \
  --add-header "ahasend-tags: product-update,announcement,cli" \
  --add-header "AhaSend-Metadata-Retention: 30" \
  --add-header "AhaSend-Data-Retention: 7" \
  --body "<html><body><h1>Product Updates</h1><p>We've launched <a href='https://yourdomain.com/new-features'>exciting new features</a>!</p></body></html>" \
  --add-header "Content-Type: text/html"

Testing with Sandbox Mode

Use sandbox mode to safely test your email integration:

swaks \
  --from hello@yourdomain.com \
  --to test@example.com \
  --server send.ahasend.com \
  --port 587 \
  --auth plain \
  --tls \
  --auth-user 'YOUR_SMTP_USERNAME' \
  --auth-password 'YOUR_SMTP_PASSWORD' \
  --header 'Subject: Sandbox Test Email' \
  --add-header "AhaSend-Sandbox: true" \
  --add-header "AhaSend-Sandbox-Result: deliver" \
  --body "This email is sent in sandbox mode for testing."

swaks \
  --from hello@yourdomain.com \
  --to test@example.com \
  --server send.ahasend.com \
  --port 587 \
  --auth plain \
  --tls \
  --auth-user 'YOUR_SMTP_USERNAME' \
  --auth-password 'YOUR_SMTP_PASSWORD' \
  --header 'Subject: Sandbox Bounce Test' \
  --add-header "AhaSend-Sandbox: true" \
  --add-header "AhaSend-Sandbox-Result: bounce" \
  --body "This email simulates a bounce for webhook testing."

swaks \
  --from hello@yourdomain.com \
  --to test@example.com \
  --server send.ahasend.com \
  --port 587 \
  --auth plain \
  --tls \
  --auth-user 'YOUR_SMTP_USERNAME' \
  --auth-password 'YOUR_SMTP_PASSWORD' \
  --header 'Subject: Verbose Sandbox Test' \
  --add-header "AhaSend-Sandbox: true" \
  --add-header "AhaSend-Sandbox-Result: deliver" \
  --body "Testing with verbose output enabled." \
  --show-data \
  --show-raw-text

Sandbox Benefits: Emails sent in sandbox mode are free, trigger webhooks normally, and never actually deliver to recipients - perfect for development and testing.

Scripting and Automation

Shell Script Example

Email Script Example

#!/bin/bash

# Configuration
SMTP_SERVER="send.ahasend.com"
SMTP_PORT="587"
SMTP_USERNAME="YOUR_SMTP_USERNAME"
SMTP_PASSWORD="YOUR_SMTP_PASSWORD"
FROM_EMAIL="hello@yourdomain.com"

# Function to send email
send_email() {
    local to_email="$1"
    local subject="$2"
    local body="$3"

    swaks \
        --from "$FROM_EMAIL" \
        --to "$to_email" \
        --server "$SMTP_SERVER" \
        --port "$SMTP_PORT" \
        --auth plain \
        --tls \
        --auth-user "$SMTP_USERNAME" \
        --auth-password "$SMTP_PASSWORD" \
        --header "Subject: $subject" \
        --body "$body"
}

# Send notification email
send_email "admin@yourdomain.com" "System Alert" "The backup process has completed successfully."

# Send welcome email
send_email "newuser@example.com" "Welcome!" "Thanks for joining our platform."

Environment Variables

For security, use environment variables for credentials:

Environment Setup

# Set environment variables
export AHASEND_SMTP_USERNAME="your_smtp_username"
export AHASEND_SMTP_PASSWORD="your_smtp_password"
export AHASEND_FROM_EMAIL="hello@yourdomain.com"

# Use in swaks command
swaks \
  --from "$AHASEND_FROM_EMAIL" \
  --to user@example.com \
  --server send.ahasend.com \
  --port 587 \
  --auth plain \
  --tls \
  --auth-user "$AHASEND_SMTP_USERNAME" \
  --auth-password "$AHASEND_SMTP_PASSWORD" \
  --header 'Subject: Secure Email' \
  --body "This email uses environment variables for credentials."

Send with the AhaSend CLI

The AhaSend CLI can also send a test email over SMTP, with ahasend smtp send. It connects to --server, which defaults to send.ahasend.com:587, and starts TLS: at once on port 465, otherwise with STARTTLS when the server offers it. AhaSend’s own servers do not offer implicit TLS on port 465, so use port 587, 25 or 2525 with them. It refuses to send the username, the password or the message to a server that offers no STARTTLS, except on localhost, 127.0.0.1 or ::1. --password-stdin reads the password from the first line of stdin, so it stays out of the process list and your shell history:

Sandbox Send with the AhaSend CLI

printf '%s\n' "$AHASEND_SMTP_PASSWORD" | ahasend smtp send --sandbox \
  --username "$AHASEND_SMTP_USERNAME" \
  --password-stdin \
  --from "$AHASEND_FROM_EMAIL" \
  --to test@example.com \
  --subject "Sandbox Test Email" \
  --text "This email is sent in sandbox mode for testing."

--test connects, starts TLS when the server offers it, logs in when you give the username and the password, and quits without sending a message:

Connection Test with the AhaSend CLI

printf '%s\n' "$AHASEND_SMTP_PASSWORD" | ahasend smtp send --test \
  --server send.ahasend.com:587 \
  --username "$AHASEND_SMTP_USERNAME" \
  --password-stdin

The CLI flags --sandbox, --sandbox-result, --tag, --track-opens and --track-clicks set the matching AhaSend headers. See ahasend smtp for every flag and exit code.

Resources

Swaks Documentation

Official Swaks documentation and manual

SMTP Testing Guide

Complete guide to testing email delivery

AhaSend SMTP Settings

SMTP server configuration and credentials

AhaSend Support

Get help from our engineering team

Pro Tip: Start with sandbox mode and basic commands before building complex automation. Use environment variables for credentials and always test scripts thoroughly before production use.

Before sending: verify your domain and create an SMTP credential.
Connection and message rules: SMTP hosts, ports and limits, special headers, sandbox mode, retention and plan features.
Other ways to send: REST API, AhaSend CLI, Node.js SDK and Go SDK.
Delivery events: webhook setup and local webhook testing.

Getting Started

Domain Authentication

Delivery and Troubleshooting

Sending with SMTP

Sending with the API

Campaign Builder

Email Tracking

Integrations

Data Retention

Security

Scaling up

Send Email from the Command Line with Swaks

Prerequisites

Installation

Connection Settings

Basic Email Examples

Advanced Examples

Using Special Headers

Testing with Sandbox Mode

Scripting and Automation

Shell Script Example

Environment Variables

Send with the AhaSend CLI

Resources

Swaks Documentation

SMTP Testing Guide

AhaSend SMTP Settings

AhaSend Support

​Prerequisites

​Installation

​Connection Settings

​Basic Email Examples

​Advanced Examples

​Using Special Headers

​Testing with Sandbox Mode

​Scripting and Automation

​Shell Script Example

​Environment Variables

​Send with the AhaSend CLI

​Resources

Swaks Documentation

SMTP Testing Guide

AhaSend SMTP Settings

AhaSend Support

​Related Guides

Prerequisites

Installation

Connection Settings

Basic Email Examples

Advanced Examples

Using Special Headers

Testing with Sandbox Mode

Scripting and Automation

Shell Script Example

Environment Variables

Send with the AhaSend CLI

Resources

Related Guides