Stop Landing in Spam: The Complete Guide to Email Deliverability in 2025

If you're running an e-commerce business, your email marketing can be a goldmine of revenue—but only if your messages actually reach your customers' inboxes. With inbox providers becoming increasingly strict about what emails make it through their filters, understanding deliverability isn't just nice to have—it's essential.

In this guide, we'll break down everything you need to know to keep your emails out of the spam folder and in front of your customers' eyes in 2025.

Understanding Email Deliverability: The Basics

First, let's clear up a common misconception: email delivery and email deliverability are not the same thing.

Email delivery is simply whether your email reaches the recipient's mail server without bouncing. Think of it as getting your letter to the right address.

Email deliverability is about where your email lands once it's delivered—inbox or spam folder? This is what actually determines whether your carefully crafted messages will ever be seen.

Four main factors influence your deliverability:

1. Who you send to and their engagement levels

2. Your sending habits (frequency and volume)

3. The content of your emails (subject lines, copy, images)

4. Your sending infrastructure (domain, IP address)

Let's dive into how to optimize each of these areas.

Building a Strong Technical Foundation

Authentication: Your Digital ID Card

Just as you need ID to enter a secure building, your emails need proper authentication to enter the inbox. In 2025, this is non-negotiable.

Set up these essential authentication protocols:

• SPF (Sender Policy Framework): Verifies that servers sending email on behalf of your domain are authorized

• DKIM (DomainKeys Identified Mail): Adds a digital signature that verifies your emails haven't been tampered with

• DMARC (Domain-based Message Authentication): Tells receiving servers what to do with emails that fail authentication

Domain Alignment: Consistency is Key

Your "From" address domain should match your sending domain. This alignment is crucial for passing DMARC checks and building trust with inbox providers.

Protect Your Main Domain

A critical best practice often overlooked: don't use your main website domain for sending emails. Instead, use a subdomain (like email.yourdomain.com or newsletter.yourdomain.com).

Why? If deliverability issues arise with your email sending, they won't affect your main domain's reputation. This separation creates a safety buffer that protects your website's ability to send transactional emails and maintain its SEO standing.

BIMI: Your Logo in the Inbox

Brand Indicators for Message Identification (BIMI) displays your logo next to your emails in supporting inboxes. This visual verification increases trust and engagement.

Smart List Management Practices

Start Clean, Stay Clean

When importing contacts or migrating to a new email service provider:

• Remove invalid emails before importing

• Exclude long-term inactive subscribers

• Verify email addresses when possible

Permission is Everything

Never, ever send to people who haven't explicitly opted in. Period.

• Implement double opt-in for new subscribers

• Keep separate segments for customers and subscribers

• Honor unsubscribe requests immediately

Regular List Cleaning

Create a segment of subscribers who haven't engaged with your emails in 90-180 days. Consider:

• Running a re-engagement campaign

• Reducing frequency to these subscribers

• Eventually removing them if they remain inactive

Develop a Sunset Strategy

Create automated flows that:

1. Identify inactive subscribers

2. Send targeted re-engagement campaigns

3. Remove or suppress those who don't respond

This keeps your list healthy and engagement metrics strong.

Content That Stays Out of Spam Filters

Subject Line Best Practices

Avoid spam triggers like:

• ALL CAPS

• Excessive punctuation!!!!!!

• Words like "FREE," "ACT NOW," or "LIMITED TIME ONLY"

• Misleading or clickbait phrases

Instead, focus on clarity, relevance, and value.

Balance Text and Images

Spam filters flag image-heavy emails with minimal text. Aim for:

• At least 500 characters of text

• ALT text for all images

• A healthy mix of images and content

Link Discipline

Too many links—especially to external domains—can trigger spam filters. Be strategic about:

• How many links you include

• Where those links point to

• Using proper tracking parameters

Personalization Matters

Personalized emails are less likely to be flagged as spam. Use your subscriber data to:

• Include first names in subject lines and greetings

• Segment based on past behavior

• Tailor content to specific interests

Gmail and Yahoo's 2024 Requirements (Still Critical in 2025)

In February 2024, Gmail and Yahoo implemented stricter sender requirements that remain essential in 2025:

1. Never use @gmail.com or @yahoo.com in your "From" address

2. Use a branded sending domain that matches your business

3. Implement DMARC at the very minimum

4. Make unsubscribing easy with one-click options

5. Keep spam complaints below 0.1%

Failing to meet these requirements will severely impact your ability to reach Gmail and Yahoo users—which likely make up a significant portion of your list.

Monitoring Your Deliverability

Regularly track these key metrics:

• Open rates: Sudden drops may indicate inbox placement issues

• Click rates: Engagement signals help your sender reputation

• Bounce rates: Keep under 2% for good standing

• Spam complaints: Stay below 0.1% at all costs

Most email service providers offer deliverability dashboards to help you monitor these metrics. Use them!

Warming Up and Ramping: Patience Pays Off

If you're just starting out or switching to a new email service provider, don't blast your entire list at once. This is a recipe for deliverability disaster.

Instead:

1. Start with small volumes to your most engaged subscribers

2. Gradually increase sending volume over 30-45 days

3. Monitor performance metrics closely during this period

4. Adjust your ramp-up schedule based on engagement

This warming process establishes your reputation with inbox providers as a legitimate sender who respects best practices.

Creating a Sending Schedule That Works

How often should you email your list? There's no one-size-fits-all answer, but:

• For engaged subscribers: 2-4 emails per week may be appropriate

• For less engaged: Consider reducing to once weekly or biweekly

• For at-risk: Send re-engagement campaigns before deciding to sunset

The key is using segmentation to send the right frequency to the right people.

Final Thoughts: Deliverability is a Marathon, Not a Sprint

Good deliverability doesn't happen overnight. It's built through consistent application of best practices over time. Focus on sending valuable, relevant content to people who want to receive it, and you'll be ahead of most senders.

Remember, email deliverability isn't just a technical challenge—it's about respecting your subscribers and providing genuine value with every send.

Struggling with email deliverability? Schedule a free strategy call today and discover how our done-for-you email marketing service can ensure your messages reach the inbox and drive consistent revenue.