Glossary of Key Terms
Term | Definition |
---|---|
Deliverability | The ability of your email to land in the user’s inbox (not the spam or promotions tab). |
ESP (Email Service Provider) | Software used to send and manage emails (e.g., Klaviyo, Mailchimp). |
Hard Bounce | A permanent email delivery failure due to invalid or nonexistent addresses. |
Soft Bounce | A temporary delivery failure due to issues like full inboxes or server downtime. |
Domain Reputation | A trust score assigned to your sending domain based on performance and behavior. |
SPF/DKIM/DMARC | Authentication protocols used to verify your domain and email legitimacy. |
IP Warming | Gradually increasing email volume from a new domain or IP to build reputation. |
Sunset Flow | Automated flow to re-engage or suppress unengaged subscribers. |
Table of contents
Why Email Deliverability Is the Unsung Hero of eCommerce Success

You can have the most beautiful email. The smartest subject line. A killer offer. But none of it matters…
If the email doesn’t reach the inbox.
Bad deliverability means:
- Wasted budget
- Poor campaign performance
- Long-term damage to your brand reputation
Great deliverability is the silent engine behind your CRM channel. It’s how you consistently land in the inbox, stay out of spam, and build real relationships at scale.
What is Email Deliverability?
Deliverability measures how many of your emails actually land in a recipient’s primary inbox. Not spam. Not promotions. Not blocked.
Inbox Placement vs. Delivery Rate
Metric | Meaning |
---|---|
Delivery Rate | % of emails that don’t bounce (delivered to mailbox somewhere) |
Inbox Placement | % of emails that land in the primary inbox (not spam/promo) |
Good deliverability:
- Avoids spam folders
- Earns high open/click rates
- Preserves long-term trust with ISPs (Google, Outlook, Yahoo)
Understanding Email Bounces (And Why They Matter)
Bounces = messages that never reach the user. They fall into two categories:
Soft Bounces
| What It Is | Temporary delivery failure | | Examples | Full inbox, server delay | | Risk | Low (unless persistent) |
Hard Bounces
| What It Is | Permanent failure | | Examples | Invalid or fake emails | | Risk | HIGH — damages sender reputation, can lead to blacklisting |
Pro Tip: Clean hard bounces weekly or after every campaign. Most ESPs (like Klaviyo) let you automate suppression.
What Is Domain Reputation and Why It Matters
Think of your domain reputation as your email credit score. The better it is, the more your emails get trusted—and delivered.
Key Factors That Affect Reputation:
Positive Signals | Negative Signals |
---|---|
High open rates | High bounce rate |
High click-through | Spam complaints |
Consistent volume | Sending to inactive lists |
Authentication (SPF/DKIM/DMARC) | Sudden spikes in sends |
9 Strategies to Maximize Email Deliverability (and Keep Revenue Flowing)
Use a Branded Sending Domain
Still sending from @klaviyo-mail.com or another ESP domain? That’s a trust killer.
Set up your own domain (e.g., hello@yourbrand.com)
- Boosts brand recognition
- Prevents “spoofing”
- Improves inbox placement
Set Up a Dedicated Sending Domain
For high-volume senders, separating marketing emails from your core domain reduces risk.
Set up email.yourbrand.com
Authenticate with SPF, DKIM, and DMARC
Pro Tip: Keep transactional (e.g., receipts) and promotional (e.g., sales) on separate domains if possible.
Authenticate with SPF, DKIM, and DMARC
These are the backbone of deliverability.
Protocol | Purpose |
---|---|
SPF | Verifies the server that sent your email |
DKIM | Validates that content wasn’t tampered with |
DMARC | Tells ISPs what to do if SPF/DKIM fail |
Set these in your DNS settings with your domain registrar (GoDaddy, Cloudflare, etc.)
Warm Your Domain and IP
New domains or IPs have zero trust. Sending too many emails too fast = spam flag.
Warm up slowly:
- Day 1: 100–500 emails to most engaged users
- Increase volume by 2x every 2–3 days
- Prioritize opens and clicks
Warming Schedule Table
Day | Volume | Audience |
---|---|---|
1–2 | 500 | Engaged segment |
3–5 | 1,000 | Engaged + warm |
6–10 | 2,500 | Add broader segment |
10+ | 5,000+ | Full active list |
Make Unsubscribing Easy
✅ One-click unsubscribe = required by Gmail and Yahoo (as of 2024)
✅ Include “Unsubscribe” in your email body and footer
Why it matters:
- Reduces spam complaints
- Improves domain trust
- Makes users feel in control
Pro Tip: Link to a preferences center if you want to reduce churn vs. hard unsubscribes.
Keep Your Email List Clean (Forever)
Inactive subscribers = spam flags.
✅ Clean your list every 30–60 days:
- Remove hard bounces
- Suppress inactive for 90+ days
- Send “re-engagement” emails before removing
List Hygiene Plan Table
Segment | Action |
---|---|
Hard Bounces | Suppress immediately |
Inactive 30–90 days | Add to re-engagement |
Unengaged 90+ days | Sunset or archive |
Stop Sending to Everyone
Mass-blasting your entire list = the fastest way to trash deliverability.
Segment by engagement:
- 0–30 Day Clickers: Send weekly
- 30–90 Day Clickers: Send bi-weekly with softer offers
- 90+ Day Inactive: Send re-engagement or sunset flow
Segment Performance Snapshot
Segment | Open Rate | CTR | Risk |
---|---|---|---|
0–30 Day Engaged | 35–50% | 5–8% | ✅ Low |
30–90 Day Engaged | 18–30% | 2–4% | ⚠️ Medium |
90+ Day Inactive | <10% | <1% | ❌ High |
Monitor Metrics Beyond Opens and Clicks
Track:
- Bounce rate (keep under 2%)
- Spam complaint rate (keep under 0.1%)
- Unsubscribe rate (keep under 1%)
- Deliverability rate (aim for 98%+)
- Inbox placement (use tools like GlockApps or Mail-Tester)
Use Sunset Flows to Clean Proactively
Send a final “are you still there?” message to inactive users
Example subject line:
“Still want to hear from us? Confirm now.”
Remove anyone who doesn’t engage in 3–5 days.
Sunset flows protect your list and boost engagement metrics over time.
Real World: The Cost of Ignoring Deliverability
At Blossom Ecom, we’ve seen:
Issue | Impact |
---|---|
ESP migration without domain warmup | Revenue drop of 35%+ |
Over-mailing entire list | Deliverability collapse in 60 days |
Ignored bounces for 6 months | Blocklisted domain |
Fixing deliverability issues | 2–5x lift in open rate & inbox placement |
Frequently Asked Questions (FAQ)
1. What’s a good benchmark for email deliverability?
Aim for 98%+ deliverability rate, <2% bounce rate, and <0.1% spam complaints.
2. How often should I clean my list?
Every 30–60 days. Use automation to suppress inactive or bounced emails after every campaign cycle.
3. Is it better to have one main sending domain or multiple?
Use at least one dedicated sending domain for promotional content. Consider separating transactional and marketing domains for high-volume senders.
4. Do open rates still matter in a privacy-first world?
Yes—but they’re less reliable post-iOS15. Focus more on clicks, conversions, and domain reputation health.
5. Should I segment my list for deliverability or performance?
Both. Segmenting improves engagement, which strengthens deliverability and boosts overall campaign performance.
6. How can I tell if I’ve been blacklisted?
Use tools like MxToolbox or GlockApps to scan your domain/IP for blocklist status. If you’re on one, stop sending and fix it fast.
Final Takeaway: Deliverability Is the Gatekeeper to Your Revenue
Your emails only make money if people see them.
Deliverability is your hidden revenue engine—and it’s often ignored until it’s too late.
✅ Don’t send blind.
✅ Don’t mass-blast.
✅ Don’t rely on “set it and forget it.”
Need Help Diagnosing or Improving Your Deliverability?
At Blossom Ecom, we specialize in fixing broken systems that leak revenue.
Whether it’s DMARC setup, list cleanup, or performance monitoring—we’ll optimize your deliverability and unlock the inbox space you paid for.
Get a Free Deliverability Audit Today
We’ll identify the silent killers in your email program and help you fix them—fast.
Because when your emails land right, your business scales right.
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