Best practices for successful email delivery

Annoyingly, ensuring delivery isn’t a straightforward science, it depends a lot on what type of sender you are. Thankfully, there are some best practices to help get you ahead, like responsive email templates, simplifying the opting out process, and email metrics monitoring.



This article was written and contributed by Rod Ussing at

Composing good email is important but making sure it successfully reaches your recipients is critical. So many well-intended messages end up in spam (60% in a recent analysis). We talk a lot about the relationship between reputation and deliverability . Now, let’s talk about how to get your email into recipients’ inboxes reliably.

A world filled with spam

Internet service providers are constantly deploying new techniques to prevent spammers from co-opting the web and crowding out legitimate consumers and business. It’s a delicate balance for them to block the bad actors and allow healthy online conversation to flourish.

As a legitimate sender of mass email (generally anything over 5000 makes you a bulk sender), you are part of that balance and there are steps you can take to make sure that your carefully crafted message actually makes it to your customers’ inbox.

Did you know? Once a bulk sender, always a bulk sender. Being a mass sender isn’t a case by case basis. The first time you hit that higher volume, you’re in the bulk sender’s club for life, and that means different inbox protocols now apply to you. Learn more in Email blasts: The dos and many don’ts of mass email sending.

Using best practices in email management is very important to your online business. Aside from the obvious benefit of maximizing the receipt of your message, following best practices will help protect your most valuable asset – your online reputation.

Composing your email

To maximize the benefit of a mass email project, make sure your email is a concise, well-crafted communication that addresses the recipient by name (e.g. using personalization with recipient variables) and has the purpose of clearly and effectively conveying an idea or describing a product as accurately as possible.

Typical elements of poor composition such as misspelled words, excessive use of caps and large fonts, odd spacing, repetitive use of exclamation marks and promotional leads such as “free” and “buy now” are precisely the type of things that will get your mail sent straight to the junk folder and risk getting your domain blacklisted.

If you’re sending an HTML email, it’s important to include a text-only version of the content for recipients without modern email clients. This is important not only from a commonsense standpoint, but it has a lot to do with whether your email gets to the recipient or is diverted as spam.

Furthermore, spammers tend to have a high ratio of HTML to text as they often favor images and frequently embed their text in an image. Spam filters are designed to filter email that contains excessive amounts of image code.

Choosing a responsive template

To strengthen the appearance and readability of your email on a variety of platforms and devices, consider using a third-party template. You can find open source templates such as these offered by Mailgun. A well-designed template will save you a lot of time, making it easy to achieve detailed personalization while providing consistency in appearance and clean rendering over a wide range of email clients and apps. Coding responsive HTML for email can be hard, but the results are worth the effort.

Use transparent configuration practices

Spammers often use address spoofing, and other obfuscation techniques to disguise their origin. Good anti-spam software is always on the lookout for bogus domains, truncated addresses, and questionable return paths. Make sure the from field, return path and message ID domains match the domain you are sending from and consider using a verified domain. If there are inconsistencies in your return path your email will likely be labeled as spam. It is also important to authenticate your email. Failure to authenticate using commonly accepted methods such as SPF, DKIM, and DMARC may result in your mail ending up in a spam filter.

Make opting out easy

Use unsubscribe links and feature them prominently. Spammers frequently use hard to see or fraudulent unsubscribe links. If your links are not prominently displayed and functional, this will decrease the credibility of your business and may get your email filtered. Monitor your unsubscribe link activity and remove those who wish to opt out of your mailing list. If you are responsive to such requests, it is more likely that recipients will click the unsubscribe button rather than report your mail as spam.

Did you know? 2024 Gmail and Yahoo inbox updates list a single-click unsubscribe process as a non-negotiable for bulk senders (over 5000 messages) for all promotional emails. Learn more in our deep dive into Gmail and Yahoo inbox updates.

In addition to a straightforward unsubscribe process, adding the extra step of “double opt-in” will help you build and maintain a healthy email list. Double opt-in is a process where after someone has filled out the signup form on your site, an email is sent to them in which they must confirm that they really want to be on your mailing list.

Monitor email activity

Successful mass emailing is more than just “fire and forget”. You should constantly be monitoring email metrics  such as bounce, open and click-through rates so you can fine-tune your email and maintain good housekeeping in your distribution lists. High open and click rates will improve your standing with providers, so make sure you drop inactive email addresses from your list. There are a number of online services that may be helpful with this process by providing easy to understand stats on your mailing such as Google Postmaster Tools and Microsoft SNDS that give targeted insights into inbox specific metrics – which is especially helpful in today’s environment where mailbox providers are cracking down on limits and protocols.

Google Postmaster Tools is integrated with Mailgun Optimize

The Mailgun Optimize suite was built to help senders tackle the most common issues preventing them from landing in the inbox. Now we're taking it one step further by providing visibility into your most essential email analytics with Google Postmaster Tools in Mailgun Optimize.

As with personal credit, your email score makes a big difference to who will do business with you, it is your reputation. A poor or nonexistent email track record may result in a poor sender score which could cause your email to be filtered straight to the spam folder. Sender scores range from 0 to 100 with scores under 70 typically ending up in spam folders. Keep in mind if your volume is low (under 5000) it may be advantageous to share an IP address as this can improve your score due to the overall higher volume coming from the shared IP address. You can monitor your reputation score with tools, such as MX Toolbox or Sender Score.

If you’re sharing an IP address, be vigilant. Make sure your ISP has a robust spam monitoring system in place, otherwise you may find your IP address blacklisted due to the actions of others.  Sometimes there can be advantages for newer senders to utilize a shared IP, but if you’re sending in bulk it’s worth considering your very own private IP.

Be on the lookout for sudden spikes in bounce rates, and routinely send test emails to your own account to check for problems. High bounce rates should be addressed immediately.

If ISP spam filters identify this as a pattern, email from your domain will be filtered. You can also get caught up in the actions of others. You never know when a spammer might start using an IP address that is close to yours. Providers sometimes filter whole blocks of IP addresses on both sides of the ones used by a spammer and if yours happens to be in this range you may find your IP address blacklisted.

Test different versions of your email

A/B testing is another important tool to ensure that your mail gets read. It consists of creating several different versions of your email with different variables such as subject line, headings, content, from name and send time. The response received from these sample emails will help you select the most effective version of email. A/B testing is quite complicated and time-consuming to set up yourself, thankfully there are subscription-based services such as Email on Acid that will do the heavy lifting for you. Or, you can do this programmatically with Mailgun.

Other spam indicators to avoid

Although it may be tempting to load your email with links to all kinds of great info and products, don’t. A high link to text ratio is a major indicator of spam. Also, watch out for those URL shorteners, they will likely get your message flagged. Remember your email will is completely ineffective in customers’ junk mail folder.

Final thoughts

If you have a great product or service, mass email sending can be a valuable tool in getting your message to the customer. A well-crafted email with clear concise language and the right amount of graphics will make your product stand out and give your customers a reason to keep reading. Add to this good email management andyour efforts will have a much bigger impact on your subscriber base and email ROI.

Mailgun helps your team increase delivery rates to your customers’ inboxes with its well documented, easy to learn API. To learn more, visit our managed services page, or feel free to contact us.

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