Founders 101: SaaS Email Deliverability — Transactional vs. Marketing Emails

Mar 31, 2025

If you're building a SaaS product, getting email classification right is critical. Learn how to avoid spam folders, protect deliverability, and stay compliant.

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 ✅

Email Type

Examples

Opt-Out Required?

Transactional

Password resets, receipts, alerts

❌ No

Marketing

Promotions, product updates

✅ Yes

Surveys

NPS, feedback requests

✅ Yes (unless triggered by user action)

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.