Email deliverability tips

This guide explains the key factors that affect email deliverability and provides actionable best practices to help your emails reach your customers' inboxes.

Deliverability factors

Email is one of the most effective marketing channels for generating revenue. However, your emails only work if they actually reach the inbox. Major inbox providers — such as Gmail and Yahoo — evaluate senders and decide whether to deliver, filter, or block messages based on a range of signals.

Four main factors influence where your emails land.

Quality and health of your contact lists

This is always important, but if you’re a new sender or your IP is new, this is all the ISP knows about you.

Have a look at the article about the health of your email list to learn to segment your email list in Bloomreach to keep it healthy and of high quality.

Frequency and relevance of emails

If you send emails every day, ISPs will be stricter with you. You need to segment your mailing list in this case. Are you sending the same message to everyone? Are you personalizing content? This will have a big impact on engagement and thus deliverability.

• Don't send too many emails. Have only the most engaged audience receiving the highest frequency of emails. An example is listed below. More emails don't necessarily mean more effective email campaigns.
• Choose quality over quantity. It is vital to prefer the quality of emails in your list over their quantity. Even though it may seem counterintuitive, the approach of sending emails to as many addresses as possible will result in lower click/open rates, therefore decreasing your sender reputation.

Content and format of the email

Content matters, but less than many marketers assume. A spammy message from a sender with a strong reputation causes fewer deliverability problems than a legitimate message from a sender with a poor one. That said, it's still worth avoiding tactics that look like spam.

Sender reputation

Sender reputation is extremely important, but not quite as in your control as the other above factors. It deserves more attention. Watch the video offered by the Bloomreach Academy to learn some of the best practices and read our further tips to maximize your sender reputation even more.

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Note

Sign up for the Mini Masterclass. Decrease spam landing, tackle deliverability challenges and much more with bite-sized videos available for free in the Engagement Mini Masterclass. For even more tips read our blog.

The Mini Masterclass also offers specific videos giving you tips on how to improve your emailing techniques during Black Friday so that you make most out of the peak seasons!

Email deliverability best practices

We’ve compiled a list of the most important best practices for email deliverability. Check to see if you’re following them and get some ideas on where you can improve.

If you follow our tips, you should increase the chances of your emails making it to your inbox. An added benefit is that your emails should be more relevant, and the customers who get them will be more engaged with them.

Fulfill necessary technical requirements

To become a reliable sender, you need to comply with a series of validation reports (SPF, DKIM), which essentially confirm that the email sender's domain is linked to your domain. This is a requirement for all Bloomreach clients.

Verify your domain

It is recommended to verify your domain with your ISPs right at the same time as fulfilling the technical requirements mentioned above. This will not directly help your email deliverability, but it is very helpful for identifying deliverability issues and for troubleshooting.

Together with the verification of your domain, you have access to ISP tools, which will provide you with information about the reputation of your domain and your IP addresses. It is recommended to check the data once in a while. These tools vary depending on the ISP. Here are links for a few of the major providers.

• Google - Postmaster, What is Postmaster?, Verify your domain.
• Yahoo - Feedback Loop
• Microsoft - Microsoft SNDS (Smart Network Data Services).

Segment your mailing list

To see how to manage your email database, see the article about the health of your email list.

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Important

Avoid spam traps. Spam traps are inactive email addresses. They can be created by spambots as mentioned above, or they can be just addresses that are not used anymore. Sending emails to these addresses damages your deliverability reputation. Fortunately, we have a feature Suppression lists to help with that.

Check the sender guidelines of your ISPs

They may include many concepts already mentioned here, but it is preferred to go through them and make sure you comply with them. Every ISP tends to have its own, for instance Gmail guidelines or Yahoo guidelines.

Ensure that your email renders for everyone

Bloomreach can help you test how your email will render across devices, apps, and browsers. Have a look at our Email previews feature. Emails that don’t render properly can result in no engagement or spam complaints. Emails that render correctly also increase your trustworthiness in the eyes of the ISPs.

Be careful about the content of your emails

Score your content using spam-checking tools, available online and free of charge. Furthermore, be aware of the size of the email. In Bloomreach, a feature will notify you when the size surpasses 102 KB, which is the maximum recommended size.

Use personalization

Personalization increases engagement rates, which is good for your sender reputation and your revenue. Reduce the batch and blast campaigns as much as possible. In other words, sending the same email to the whole mailing list isn't the preferred strategy.

The more you can tailor the email to the individual customer, and go beyond just using first names. Incorporate things like behavioral data, purchase data, and user preferences. Here is an article about a personalized subject line to get you started.

Maintain a proper text-to-image ratio

60:40 in favor of text is a sensible guideline, although taking into account the attractiveness of the visual aspect, 50:50 is acceptable as well.

Make your sign-up process memorable

People who remember signing up for your emails are less likely to report you as spam, which will result in a better sender reputation.

Use double opt-in

Similarly, if the customer confirms their interest, the likelihood of their reporting your email as spam significantly decreases. Furthermore, you will also avoid hitting spam traps. Check out our Double opt-in business use case article. A good double opt-in program should have a 70% success rate.

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Note

Bloomreach can help you with an out-of-the-box Plug & Play Double opt-in scenario, please contact your CSM if you are interested!

Include CAPTCHA to prevent spam bots from signing up to your list

Spambots may attack your sign-up, resulting in filling up your email list with artificially created email addresses.

Make the unsubscribe process as easy as possible

If someone doesn’t want to receive your emails, let them opt out as easily as possible. This way, they won’t report you as spam, and therefore, your sender reputation won’t be damaged. See also List unsubscribe article about our feature, making the unsubscribe process even easier.

Review your campaign reports at an ISP level

Monitor bounce and complaint rates at an ISP level and look for signs (dips in open/click rates) of your emails being bulk sent to spam for certain ISPs. This is something you want to avoid, as it significantly decreases your sender reputation.

Oftentimes, if you use good email practices, the dips in open/click rates may be happening only on a specific ISP, it is beneficial to be able to know where the blocking of emails is happening for further analysis of the problem. This can be done using an email domain report.

Check blocklists

It is recommended to check whether you are to be found on a blocklist. That would prevent your emails from reaching the customer's inbox. Here is a tool you can use for this purpose: Blocklist check.

Precedence: bulk

The Precedence email header is used to classify emails based on their type by ISPs. It is important to have the precedence set to bulk (indicating that the email is sent to many people). Otherwise, it is more likely that the ISPs will direct your message to the recipient's spam folder.

In Bloomreach, you need to check the box for the usage of bulk settings. The checkbox may be found while creating an email campaign (either directly through Email campaigns or Scenarios ) under Design > Settings.

What to avoid

• Don’t buy, rent, or harvest email addresses: You need to know the quality of your mailing list. If you’re buying addresses in bulk, knowing exactly what you’re getting isn't easy. This can be a violation of guidelines like the GDPR.

• Don’t send emails to people who don’t want or can't receive them: This can also violate the GDPR and likely result in more spam complaints.

• Don’t send emails to users who haven't opted in: GDPR prohibits this. Doing so would drive up spam complaints and destroy your sender's reputation.

• Don’t send emails to old or inactive addresses: These customers aren’t adding revenue to your business and are hurting your metrics. It’s a good idea to cut off email addresses without engagement within the last 180 days and transfer these accounts to a re-engagement (or even a re-permission) program. You can also use our Email List Hygiene Filter to automatically block emails from being sent to inactive addresses.

• Don’t use spammy language: Using all CAPS, ending sentences with lots of punctuation (!!!), using too much “super-hot exclusive sale!” terminology. ISPs don’t like any of it, and neither do your customers.

• Don’t send too many emails: We recommend sticking with the convention of not sending more than one email per day. Adjust your email frequency to email engagement. Only your most engaged audiences should receive the most emails. You can use list segmentation to help manage this or our built-in Frequency policies. The reduction of the frequency of emails is a proven tactic for re-engaging a less engaged audience. Here is an example of how that could be divided.

Advanced strategies

Read our blog about Email marketing analytics about metrics, KPIs, and reports.