Email Deliverability Tips

Email is considered to be the most effective marketing channel for revenue generation and email deliverability is extremely relevant to the success of your email campaigns.

Its objective is for the email to reach the customer’s inbox.
Major Inbox Providers (such as Gmail or Yahoo) have processes defining a good email sender, determining whether the objective will or will not be fulfilled.

In this guide you will find:

  • What are the deliverability factors
  • Tips - what to do
  • Tips - what to avoid doing

Deliverability factors

Deliverability factors influence whether the email will be successfully delivered to your customer's inbox instead of for instance the e-mails getting blocked or delivered straight to the customer’s spam folder. The four main factors are:

  1. Quality/health of contact lists


Visit the article about the health of your email list to learn to effectively divide up your email list in Exponea in order for it to be healthy and of high quality.

  1. Sender reputation (follow the tips below to maximize your sender reputation)
  2. Frequency and relevance of e-mails


Do not send too many emails

Have only the most engaged audience receiving the highest frequency of emails. An example is listed below. More sent emails don't necessarily mean more effective email campaigns.

  1. Content of the email

Down below you can find tips and best practices to improve your email deliverability.


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.

TIPS - What to do?

  • Fulfill necessary technical requirements
    In order 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 of the Exponea 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 will 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.

  • Include CAPTCHA to prevent spam bots signing up to your list
    Spambots may attack your sign-up, resulting in filling up your email list by artificially created email addresses.


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 extremely damages your deliverability reputation.

  • Double opt-in is highly recommended
    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.

  • Ensure that your email renders well on all main email apps and devices
    ISPs prefer e-mails which render correctly as it increases their trustworthiness.

  • Use personalization
    Reduce the batch and blast campaigns as much as possible. In other words, sending the same email to the whole mailing list is not the preferred strategy. The more you can tailor the email to the individual customer (based on purchase, web data or preference data), the higher the email engagement. Here is an article about a personalized subject line.

  • 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 for analysis
    Monitor bounce and complaint rates by all of your ISPs. In addition, track dips in open/click rates by ISP for evidence of bulking (e-mail going straight to junk). This is something you want to avoid, as it significantly decreases your sender reputation.
    Oftentimes, if you use good emailing practices, the dips in open/click rates may be happening only on a specific ISP, therefore it is beneficial to be able to know where the blocking of emails is happening for the further analysis of the problem. This can be done using an email domain report.

  • Check blacklists
    It is recommended to check whether you are to be found on a blacklist. That would prevent your emails from reaching the inbox of the customer.
    Here is a tool you can use for this purpose: Blacklist check.

  • Precedence: bulk
    "Precedence" email header is used to classify emails based on its 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 Exponea, you need to check the box for the usage of bulk settings as shown in the picture. The checkbox may be found while creating an email campaign (either directly through "Email campaigns" or "Scenarios" ) under "Design>Settings".

  • Make your acquisition method memorable
    People who remember signing up for the email subscription are less likely to report your as spam, which will result in better sender reputation.

  • Be careful about the content of your emails
    Score your content using spam checking tools, available also online and free of charge. Furthermore, be aware of the size of the email. In Exponea, a feature will notify you when the size surpasses 102 KB, which is the maximum recommended size.

  • Consider your 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.

  • Check 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.

TIPS - What to avoid doing?

  • Don’t buy, rent or harvest e-mail addresses
    In other words, know the quality of your email list.

  • Don’t send emails to people who don’t want them or cannot receive them

  • Don’t send emails to users who have not opted-in
    First and foremost, GDPR prohibits you to do so. In addition, it would significantly drive up spam complaints and destroy your sender reputation.

  • Don’t send emails to old or inactive addresses
    The recommended cut off point should be 180 days since the last open or click.

  • Don’t use vocabulary, which may resemble spam emails
    Such as but not limited to multiple exclamation points or extensively used upper-case letters (caps-lock).

  • Do not send too many emails
    We recommend sticking with the convention of not sending more than one email per day. Furthermore, as mentioned also at the beginning of the article, adjust your email frequency to email engagement. The reduction of frequency of emails is a proven tactic for re-engaging a less engaged audience. Here is an example of how that could be divided.

People whose last open or click is in the last 30 days

3+ emails a week

People whose last open or click is between 31 and 90 days

2 emails a week

People whose last open or click is between 91 and 180 days

1 email a week


Advanced strategies

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

Updated 4 days ago

Email Deliverability Tips

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