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Transactional Email (FrontEngine)

FrontEngine is InteSys's transactional email platform, purpose-built for application-generated messages like order confirmations, password resets, shipping notifications, and account alerts.

Overview

Unlike marketing email platforms, FrontEngine is optimized for high deliverability of individual, triggered messages. Every email is sent from managed IP addresses with actively maintained sender reputation.

Sending Methods

Method Best For
SMTP Relay Drop-in replacement for existing SMTP configurations; works with any language or framework
REST API Modern applications that prefer HTTP-based integration with JSON payloads

Key Features

  • Dedicated IP addresses with managed reputation and warm-up
  • High deliverability through SPF, DKIM, and DMARC alignment
  • Real-time webhooks for delivery, bounce, open, and click events
  • Detailed analytics — track delivery rates, opens, clicks, and bounces per message or domain
  • Template support — define reusable HTML templates with variable substitution
  • Rate limiting — configurable sending rates to match your domain's reputation
  • Multi-domain — send from multiple domains under a single account

SMTP Relay

Connect your application to FrontEngine using standard SMTP credentials:

Setting Value
Server smtp.frontengine.intesys.io
Port 587 (STARTTLS) or 465 (SSL)
Username Your API key
Password Your API secret
Authentication PLAIN or LOGIN 
import smtplib
from email.mime.text import MIMEText

msg = MIMEText("Your order #12345 has been shipped.")
msg["Subject"] = "Order Shipped"
msg["From"] = "[email protected]"
msg["To"] = "[email protected]"

with smtplib.SMTP("smtp.frontengine.intesys.io", 587) as server:
    server.starttls()
    server.login("your-api-key", "your-api-secret")
    server.send_message(msg)

REST API

Send messages via HTTP POST with JSON payloads. The API supports single and batch sends, template rendering, and attachment handling.

curl -X POST https://app1.frontengine.net/api/v1/send/message \
  -H "X-Server-API-Key: your-api-key" \
  -H "Content-Type: application/json" \
  -d '{
    "from": "[email protected]",
    "to": ["[email protected]"],
    "subject": "Order Shipped",
    "html_body": "<h1>Your order has shipped!</h1><p>Tracking: ABC123</p>"
  }'

→ Full API Reference

Getting Started

  1. Create an API key in the Client Portal under Services > Transactional Email > API Keys
  2. Configure your sending domain with SPF, DKIM, and DMARC records — see Authentication Guide
  3. Send a test message using SMTP or the REST API
  4. Set up webhooks to track delivery events — see Webhooks

Test Mode

Use the X-Test-Mode: true header to validate API requests without actually sending email. Test mode messages return a 200 response but are not delivered.

Deliverability Best Practices

  • Always authenticate your sending domain with SPF, DKIM, and DMARC
  • Use a consistent "From" address — frequent changes hurt reputation
  • Include a plain-text version alongside HTML
  • Process bounces promptly and remove invalid addresses
  • Warm up new IP addresses gradually (start with 100-500 emails/day)

Next Steps