If you’re building a SaaS product, one of the most overlooked (yet critical) foundations is this: how you classify your emails.

Get this wrong and your emails may never reach your users. Worse? You could violate major regulations like CAN-SPAM, GDPR, or CCPA.

Here’s your quick-start cheat sheet to email deliverability—the way I wish someone handed it to me when we first started shipping software.

🔄 Transactional vs. Marketing Emails: What's the Difference?

Not all emails are created equal. And email service providers (ESPs), privacy laws, and spam filters all treat them differently.

Let’s break it down:

✅ Transactional Emails (a.k.a. “Let the product work” emails)

These are triggered by a user’s action and are essential to your app’s functionality. Think receipts, password resets, or subscription confirmations.

Common Examples:

• Password reset emails

• Purchase receipts

• Subscription or sign-up confirmations

• System alerts or notifications

Rules to follow:

• ❌ No opt-out/unsubscribe required

• ✅ Typically exempt from marketing laws (CAN-SPAM, GDPR), if strictly transactional

• ❌ Avoid adding promotions or marketing content to these—they’ll lose their protected status

📣 Marketing & Non-Transactional Emails (a.k.a. “The ones that get you in trouble”)

These are proactive. You're reaching out to promote, engage, or survey.

Common Examples:

• “We miss you” re-engagement emails

• Product updates and feature launches

• Onboarding drip sequences or tips

• NPS or satisfaction surveys

• Promotional offers or announcements

Rules to follow:

• ✅ Opt-out/unsubscribe link is required

• ✅ Must include your company name and physical mailing address

• ✅ GDPR/CCPA often require explicit opt-in, especially for European users

💡 Pro tip: If you’re not sure if it’s marketing, it probably is.

🧠 Pro Tips from the Email Trenches

Want to keep your deliverability rates sky-high and stay compliant? Here’s what we’ve learned helping SaaS founders ship with confidence:

• Label emails properly in your ESP
  (Postmark, SendGrid, Mailgun, etc.) → Mislabeling = deliverability nightmares

• Use separate sending domains or IPs for transactional vs. marketing
  → Keeps your critical emails (like password resets) from being flagged

• Surveys are NOT always transactional
  → Unless they’re triggered by user behavior (like after a cancellation), assume they’re marketing

• Respect user preferences even if the law doesn’t require it
  → Doing what’s right builds trust and long-term retention

✅ Quick Email Classification Guide

Final Thoughts: Don't Let Emails Derail Your SaaS

Email classification might seem like a minor technicality—but if your users don’t get critical messages (or worse, start marking them as spam), it’s a huge hit to your product experience and trust.

At Eight Bit Studios, we’ve helped dozens of startups build smart, scalable communication systems from day one. Want a second set of eyes on your setup? Let's chat.