Email marketing remains one of the most powerful tools for businesses to communicate with their audience, whether it’s driving engagement, nurturing leads or boosting conversions. But the success of an email marketing campaign hinges on one crucial factor: deliverability. If your messages aren’t seen in the inbox, your hard work goes to waste.
At our recent Constant Contact APAC Marketing Lab, Jon Marburger, our email marketing expert, revealed the top six best practices for email deliverability.
Leading a team that monitors an astonishing 100 billion emails each year, Jon also cultivates vital relationships with industry giants like Google and Yahoo, ensuring emails reach their destination effectively. When Jon talks email, we take notes—because he knows how to make every message count!
In this article, we explore the key email deliverability strategies, featuring Jon’s expert insights and actionable tips to help you reach your subscribers more effectively.
The Journey from Delivery to Email Deliverability
1. Maintain a Clean, Up-to-Date Email List
The foundation of good email deliverability starts with a clean email list. Over time, subscriber lists accumulate inactive, outdated, or invalid addresses that can harm your sender reputation. When you send emails to these addresses, it can result in high bounce rates, signalling to email service providers (ESPs) that you’re not maintaining a quality list. This may result in your mail being flagged as spam, or even blocked entirely.
Best practices for maintaining a clean list include:
• Regular List Hygiene: Periodically review your email list to remove inactive or invalid addresses. This means identifying and removing hard bounces (permanently undeliverable emails) and soft bounces (temporary issues) after a certain number of attempts.
• Engagement-Based Segmentation: Segment your list based on engagement levels. For example, create a segment for highly engaged subscribers and another for those who haven’t opened an email in the past 3-6 months.
• Double Opt-In: Ensure your subscribers genuinely want to receive your emails by using a double opt-in process. This requires subscribers to confirm their email address by clicking on a link in a confirmation email, which reduces the risk of fake or mistyped addresses.
2. Use Authentication to Build Trust
Email authentication is one of the most critical aspects of email deliverability best practices. It verifies your identity as a sender and helps ESPs distinguish your emails from spam or phishing attempts. Without proper authentication, ESPs may mark your mail as untrustworthy and send them to spam folders.
There are three key email authentication protocols that you can implement to improve deliverability:
• Sender Policy Framework: SPF ensures that only authorised IP addresses can send emails on behalf of your domain. This prevents spammers from using your domain to send fraudulent emails.
• DomainKeys Identified Mail: DKIM adds a digital signature to your emails, verifying that they haven’t been altered in transit and they’re actually coming from your domain.
• Domain-based Message Authentication, Reporting and Conformance: DMARC builds on SPF and DKIM by adding a layer of reporting and enforcement. It allows you to tell ESPs how to handle emails that fail SPF or DKIM checks.
3. Optimise Email Content for Deliverability
While it’s essential to create compelling email content, it’s equally important to ensure your content doesn’t trigger spam filters. ESPs use sophisticated algorithms to analyse emails and determine whether they look suspicious or resemble spam.
Here are a few tips for optimising email content for deliverability:
• Avoid Trigger Words: Certain words and phrases can cause your emails to be flagged as spam. Examples include “free,” “urgent,” “win big,” and “limited time offer.” While these phrases may seem enticing for marketing purposes, they can harm deliverability.
• Limit the Use of Symbols: Overusing symbols like exclamation points or dollar signs can also trigger spam filters. Keep your subject lines and body text professional and free of excessive punctuation.
• Balanced Text-to-Image Ratio: While images can enhance your email’s visual appeal, too many images and not enough text can raise red flags with ESPs. Aim for a balance between images and text.
• Alt Text for Images: Always include alt text for your images. This ensures that even if the images don’t load, the recipient can still understand the message.
4. Focus on Subscriber Engagement
Engagement is one of the most important factors that ESPs consider when determining whether to deliver your emails to the inbox or the spam folder. If your emails consistently generate low engagement (e.g. low open rates, clicks and replies), ESPs may assume your content isn’t relevant or desired by your recipients.
Here’s how to improve engagement and, by extension, deliverability:
• Personalisation: Personalising your emails with the recipient’s name, location, or previous purchase history can make your emails feel more relevant and increase open rates.
• Segmented Campaigns: Sending the same message to your entire email list is no longer effective. Instead, segment your list based on factors like demographics, behaviour, or purchase history. This allows you to send highly targeted emails that are more likely to resonate with each group.
• A/B Testing: Continuously test different aspects of your emails, like subject lines, content and CTAs, to see what works best. This helps you optimise future campaigns.
5. Monitor Your Sender Reputation
Your sender reputation plays a major role in whether your messages are delivered to inboxes or spam folders. ESPs assign a reputation score to every sender based on factors like bounce rates, spam complaints and engagement metrics. If your reputation is poor, your emails are more likely to be blocked or sent to spam.
To maintain a positive sender reputation, follow these steps:
• Keep Bounce Rates Low: A high bounce rate indicates that you’re sending emails to invalid or outdated addresses, which damages your reputation. Regularly clean your email list to keep bounce rates down.
• Monitor Spam Complaints: If a large number of recipients mark your emails as spam, it will negatively impact your sender reputation. Make sure your emails are relevant and not overly promotional.
• Engage with Active Subscribers: Focus your efforts on engaging with subscribers who are actively opening your emails. Repeatedly contacting disengaged or inactive subscribers can hurt your reputation.
6. Ensure Compliance with Industry Regulations
Compliance with email marketing regulations is not only a legal requirement but also crucial for maintaining email deliverability best practices. Laws like the Australian Spam Act 2003, General Data Protection Regulation (GDPR) and the CAN-SPAM Act outline specific rules for obtaining consent from subscribers and handling unsubscribe requests.
To ensure compliance:
• Obtain Explicit Consent: Always get permission from your subscribers before sending marketing emails. This is typically done through an opt-in process, where subscribers knowingly agree to receive emails.
• Include an Unsubscribe Option: Every marketing email must include an easy-to-find unsubscribe link. Failure to do so can result in penalties and a drop in deliverability.
• Respect Privacy: Be transparent about how you use subscriber data and always respect their privacy. Sending unsolicited emails can lead to spam complaints, which harms your deliverability.
Email Deliverability Best Practices Decoded
Deliverability is critical to the success of your email marketing campaigns. By maintaining a clean list, using proper authentication, optimising content, focusing on engagement, monitoring your sender reputation, and ensuring compliance with regulations, you can significantly improve your deliverability rates.
Following these best practices will help ensure your emails reach the inbox and achieve the desired results. Remember, deliverability is not a one-time effort — it requires ongoing attention and optimisation to maintain long-term success.
Now that you’ve mastered the essentials of email deliverability, what’s next?
Dive into our articles on crafting high-performing Welcome Emails and boosting Subscriber Engagement to take your email strategy to the next level!
About Jon Marburger, Director of Email Deliverability, Constant Contact
With a background in physics, Jon specialises in email compliance, delivery and deliverability at Constant Contact. Jon is an expert on IP and domain reputation monitoring, compliance tooling and email analytics. Since 2020, he’s been co-chair of the Senders Committee as part of the Messaging, Malware and Mobile Anti-Abuse Working Group (M3AAWG), where voices from all sectors of the email industry work together to make sending safer.
