Email Deliverability Best Practices to Reach the Inbox in 2025

Email marketing remains a cornerstone of e-commerce. As many digital marketers know, email campaigns are some of the most profitable and reliable ways of reaching your target audience. While email marketing has many nuances, we’re focusing on the very first challenge: reaching your recipient’s inbox.

An email being delivered doesn't guarantee it reaches the recipient's inbox. It might have been filtered into a promotions tab or the spam folder.

Below, we’ll explore common reasons why your email deliverability may be lacking and how you can improve inbox placement for 2025.

How can you reach the inbox in 2025?

1. Content Quality

Content plays a vital role in ensuring emails reach the inbox. Follow these guidelines to improve your email deliverability:

• Subject Lines: Be truthful and transparent in your subject line. Identify your brand clearly in the sender field and avoid spammy words like “Free,” “Win,” or “Dear.” Never use all caps. Studies show that subject lines with 6-10 words achieve 21% higher open rates than shorter or longer ones.
• Mobile-Friendly Design: Around the globe, nearly 2 billion people regularly check emails on their mobile devices. Around 81% of emails are opened on mobile devices. Ensure your emails are mobile-friendly to protect engagement metrics and maintain your sender reputation.
• URLs: Avoid URL shortening services and link only to websites with good IP reputations. Certain types of links can trigger spam filters.

2. Sender Reputation

Your sender reputation significantly impacts email deliverability. Follow these practices to maintain a strong reputation:

• Easy Unsubscribe Process: Make unsubscribe options visible and easy to use. Difficult unsubscription processes can harm your reputation in the long term.
• Contact List Quality: Always verify your email lists to avoid hard bounces. Email addresses decay at a rate of 20% annually, making regular verification critical. Verifying your contact lists 24 hours prior to sending your campaigns out is the safest way to ensure a low bounce rate.

3. Emailing Consistency and Engagement

Consistency in your email marketing patterns is more important than you might think. Even small, abrupt changes can negatively impact deliverability.

• Maintain Patterns: Stick to a consistent schedule, but make changes gradually.
• Engage Customers: Customers who interact with your emails are more likely to keep your emails out of spam folders. Emails with personalized subject lines see 50% higher open rates. Tailor your campaigns based on engagement metrics.

4. Domain Authentication and Safety

Set up authentication protocols such as DKIM, SPF, and DMARC. These protocols protect your domain’s reputation and maximize deliverability.

DMARC adoption continues to rise, with over 85% of Fortune 500 companies implementing it for 2025 to safeguard deliverability and prevent phishing attacks. However, these protocols aren’t just for large corporations and it is vital for small and medium sized businesses to have proper authentication records. Security is one of the most impactful concepts in your deliverability. It generates trust in your customers and partners and helps maximize your success.

5. Email Volume

Large changes in volume can cause deliverability issues, so it’s important to know how to handle large quantities of outgoing emails.

• Segment Your Lists: Target relevant audiences to reduce email volume and increase engagement.
• Follow Best Practices: Adhere to all industry standards when sending large numbers of emails. Follow your ESP’s guidelines and split your large sends into smaller chunks over time.

6. Double Opt-In vs. Single Opt-In

Using double opt-ins for email subscriptions helps ensure high-quality subscribers. While single opt-ins require less effort from users, double opt-ins improve email deliverability by verifying subscriber intent and reducing the likelihood of spam complaints.

Double opt-ins result in 20% fewer spam complaints compared to single opt-ins. This helps protect your reputation with your ESP.

7. Blacklist Monitoring

Use a blacklist monitoring tool to ensure your sending IP isn’t listed. If it is, take immediate action to be delisted. Monitor the health of your IP addresses if you use shared IP pools to send emails. Contact your service provider if any are blacklisted.

8. Deliverability Insight Tools

Deliverability tools provide valuable insights, including:

• Authentication checks
• Content and syntax analysis
• Inbox placement reports
• Blacklist monitoring

Using these tools before launching a campaign helps you identify and address potential issues proactively, maximizing your campaign outcome and helping you succeed on your key performance indicator metrics.

Summary

Here’s a quick recap of the strategies to reach the inbox in 2025:

• Content: Use transparent subject lines, mobile-friendly designs, and reliable URLs.
• Reputation: Provide easy unsubscribe options and verify email lists regularly.
• Consistency and Engagement: Stick to a consistent schedule and tailor campaigns to customer engagement patterns.
• Authentication and Infrastructure: Ensure your emails are authenticated with DKIM, SPF, and DMARC.
• Email Volume: Segment your lists and follow best practices.
• Double Opt-In: Use double opt-ins to maintain high-quality subscribers.
• Blacklist Monitoring: Regularly check and maintain your IP’s reputation.
• Deliverability Tools: Leverage tools to analyze and optimize inbox placement.