Sending Transactional Email with MailChannels: A Complete Guide If you’re building an app or service that sends real-time messages—like password resets, order confirmations, or signup verifications—transactional email is essential. And when it comes to reliable, secure, high-deliverability infrastructure, MailChannels is a top choice. This guide walks you through how to start sending transactional email with MailChannels, whether you use SMTP relay or integrate directly with our API. What Is Transactional Email? Transactional emails are messages triggered by user actions or system events. They’re not marketing—they’re functional, expected communications your users rely on. Learn more: Transactional vs Marketing Email 1. Sending via SMTP Relay SMTP is the simplest way to start. It lets you route transactional messages through MailChannels using your existing mail client or library. Step-by-step: Sending via SMTP Relay 2. Integrating the MailChannels Email API If you need more control, speed, and visibility, our HTTP-based API gives developers a programmatic way to send scalable, reliable email. Tutorial: MailChannels Email API with code examples 3. Choosing Between SMTP and API Not sure which to use? Each method has unique strengths depending on your stack and use case. Compare SMTP vs API 4. MailChannels vs Other Providers Evaluating options like SendGrid, Postmark, or Mailgun? We break down the differences across deliverability, cost efficiency, and abuse prevention. Compare MailChannels vs other providers 5. Troubleshooting Setup Issues Running into setup issues? Common problems include DNS misconfigurations and blocked ports. Our guide walks you through quick fixes. Fix common setup issues 6. Best Practices for IP Warmup Sending from a new IP or domain? Warming up your sending reputation is critical for inbox placement, especially when scaling transactional volume. Guide: IP Warmup with MailChannels Final Thoughts MailChannels makes it simple to deliver transactional emails reliably, securely, and at scale. From login links to shipping confirmations, we’re built to keep your messages out of spam and in front of users. Get started with the MailChannels Email API and send with confidence.