MailSet Blog

Email deliverability is the foundation of every successful email marketing campaign. Without reaching your subscribers' inbox, even the most compelling content won't drive results. In this guide, we'll cover the proven strategies to ensure your emails land in the inbox not the spam folder.

What Is Email Deliverability?

Email deliverability refers to the ability of your email to reach the inbox of your subscribers without being blocked, filtered, or marked as spam. It's a combination of technical setup, sending practices, and content quality.

The Core Elements of Deliverability

1. Authentication Protocols (SPF, DKIM, DMARC)

Email authentication protocols verify that your emails are genuinely from you. These three protocols work together to build trust with email providers:

• SPF (Sender Policy Framework): Authorizes specific mail servers to send emails on behalf of your domain.
• DKIM (DomainKeys Identified Mail): Uses cryptographic signatures to verify message integrity and sender identity.
• DMARC (Domain-based Message Authentication): Builds on SPF and DKIM to prevent domain spoofing and specify what happens to unauthorized messages.

2. Sender Reputation

ISPs (Internet Service Providers) monitor your sending reputation through metrics including:

• Bounce rates (both hard and soft bounces)
• Complaint rates (spam reports)
• List quality and engagement metrics
• IP address history and behavior

A good sender reputation is crucial aim to keep bounce rates below 2% and complaint rates below 0.1%.

3. List Hygiene

Maintaining a clean email list directly impacts deliverability:

• Remove hard bounces immediately
• Implement double opt-in to verify email addresses
• Re-engage inactive subscribers regularly
• Suppress permanently disengaged users after 6-12 months
• Validate new email addresses at signup

Practical Action Steps

1. Set up authentication: Configure SPF, DKIM, and DMARC records in your DNS settings
2. Monitor metrics: Track open rates, click rates, and bounces regularly
3. Clean your list: Audit your subscriber list and remove invalid addresses
4. Warm up IP addresses: If using a dedicated IP, gradually increase sending volume
5. Test before sending: Use a tool like MailTester to check subject lines and content for spam triggers
6. Segment by engagement: Send to engaged users more frequently; inactive users less frequently

Common Deliverability Mistakes to Avoid

Buying email lists: Always use permission-based lists. Purchased lists have low engagement and hurt your reputation.

Ignoring bounce notifications: Remove bounced addresses from future sends immediately.

Sending to spam traps: Avoid abandoned email addresses that ISPs monitor as spam traps.

Using suspicious links: Shortened URLs and frequently flagged domains trigger spam filters.

Real Case Study: E-commerce Store Recovery

A clothing retailer was struggling with deliverability. Their open rates had dropped to 8%, and support was flooded with complaints that emails weren't arriving. After implementing SPF/DKIM/DMARC authentication, removing 15,000 inactive subscribers, and implementing a re-engagement campaign, their open rate improved to 22% within 60 days.

Key Takeaways

Deliverability isn't about luck it's about following best practices. Set up your authentication, keep your list clean, and monitor your metrics. These fundamentals will ensure your emails reach your subscribers' inbox consistently.

Sending the same email to your entire list is like yelling in a crowded room everyone hears the message, but it's not relevant to anyone. Segmentation is the antidote. By dividing your audience into smaller, more specific groups, you can send personalized messages that drive higher engagement and revenue.

What Is Email Segmentation?

Email segmentation is the practice of dividing your subscriber list into distinct groups based on shared characteristics or behaviors. Each segment then receives targeted emails relevant to their specific needs and interests.

Key Segmentation Strategies

1. Demographic Segmentation

Divide by basic characteristics like:

• Age, gender, location
• Job title or industry
• Company size
• Education level

Example: A fitness brand sends different messages to ages 18-30 vs. 40-60 based on exercise preferences and health goals.

2. Behavioral Segmentation

Segment based on what subscribers do:

• Purchase history (buyers vs. browsers)
• Email engagement (openers vs. non-openers)
• Website activity (pages visited, products viewed)
• Link clicks (interested in specific topics)

Example: A software company sends advanced feature tutorials to users who click product links, but sends basic how-to guides to users who never click.

3. Lifecycle Segmentation

Divide by customer journey stage:

• Prospects: New subscribers, no purchase
• Customers: Made at least one purchase
• Loyal Customers: Repeat purchasers
• At Risk: Previously active but now inactive

Example: Prospects get nurture content focused on education. Loyal customers get VIP offers and early access to new products.

4. Interest-Based Segmentation

Segment by the topics subscribers care about:

• Preference center selections (e.g., interested in weekly sales, product updates, educational content)
• Survey responses
• Content downloads (what ebooks they downloaded)

Example: E-commerce store segments subscribers interested in "Men's Shoes" from "Women's Accessories" and sends relevant recommendations to each.

How to Implement Segmentation

Step 1: Collect Data

You need information to segment effectively:

• Signup forms (ask for location, role, interests at signup)
• Preference centers (let subscribers choose topics)
• Behavioral tracking (monitor clicks, purchases, page views)
• CRM data (import purchase history, customer type)

Step 2: Create Segments in Your Email Platform

Define clear rules for each segment. Example: "High-value customers = purchased 3+ times with total spend >$500"

Step 3: Build Targeted Campaigns

Create unique email versions for each segment:

• Different subject lines (speak to their interests)
• Different content (relevant to their needs)
• Different CTAs (guide them along their journey)

Step 4: Measure and Optimize

Compare performance across segments. Which segment has the highest open rate? Which has the best conversion? Use these insights to refine your approach.

Segmentation Impact: The Numbers

Studies show that segmented campaigns dramatically outperform one-size-fits-all campaigns:

• 58% increase in open rates with segmented campaigns
• 100% increase in click rates
• 4.5x increase in conversion rates

Simple Segmentation to Start With

You don't need to be complex. Start with these basic segments if you're new to segmentation:

• Engaged (opened in last 30 days) vs. Unengaged: Send reactivation campaigns to unengaged; regular campaigns to engaged.
• Customers vs. Prospects: Send product offers to customers; education content to prospects.
• By Signup Source: Twitter followers get different content than blog subscribers.

Real Example: E-commerce Success

A fashion retailer implemented basic segmentation:

• Segment 1 (Men) receive men's discounts and recommendations
• Segment 2 (Women) receive women's discounts and recommendations
• Segment 3 (Active Buyers) receive exclusive early-access sales
• Segment 4 (Window Shoppers) receive top-seller recommendations

Result: Open rates increased from 18% to 28%, and revenue per email nearly doubled.

Key Takeaways

Segmentation is a game-changer for email marketing. Even basic segmentation dividing by gender, location, or purchase history delivers measurable improvements. Start simple, measure results, and expand as you learn what works for your audience.