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Andrea Serventi
3 August 2017
Reading time: 6 min

Email Deliverability: Do’s and Dont’s to Make Sure Your Campaigns are Delivered

When a brand sends an email to one of its customers, regardless of whether it is a promotional or transactional communication, the fact that it appears in the recipient’s inbox is taken for granted. In short, those sending the emails believe that simply sending it = delivery. However, this is not exactly the case.

The first email was sent as long ago as 1971, and an era has passed since then: today, every day, an average 225 billion messages are sent via email worldwide. This rate is steadily growing, and according to Radicati, in 2020 it will hit the 257 billion mark.

But now let’s look at the other side of the matter, delivery, relying on a different study: ReturnPath estimated that about a quarter (22% to be precise) of emails that are sent to recipients who have given their consent to receive communications do not reach their inboxes.

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An email’s correct (or failed) delivery depends on several factors. The key word to keep in mind is deliverability, i.e. an email’s ability to reach the inboxes of recipients and avoid ending up in the spam inbox.

All too often deliverability is only considered when a brand’s sending performance  (opening and clicking rates) takes on a negative trend. Instead of solving problems once they emerge, adopting a proactive approach is advisable, as it allows you to safeguard email deliveries over time. To help you, we have identified the key points that a brand should pay attention to to ensure that the percentage of emails that get lost and don’t reach recipients is minimized.


1. Adopt the double opt-in system

This is a newsletter subscription system which, unlike the single opt-in system, provides a further step in confirming registration. Once the form is completed and the request has been sent, the new contact must click on the confirmation email that is sent automatically. This method ensures that the email address entered is valid and actually belongs to the user.

Through verifying the email addresses, the double opt-in system allows you to minimize the bounce rate, which has a negative impact on many brands’ reputations and causes problems with deliverability. Having a clean list of contacts lets you maintain high deliverability standards, which translate into higher delivery rates.

The double opt-in system lets you feed your database with valid addresses and keep lists clean from the start, without having to struggle later on in an attempt to recover a damaged reputation.

2. Make unsubscription accessible and fast

Obstructing (more or less voluntarily) the unsubscription process is counterproductive. What is a contact forced to do if he can’t quickly unsubscribe from a newsletter? He will be forced to use the spam button, disadvantaging the brand as a whole.

Confirming this dynamic is the joint research by Litmus and Fluent, which found that 50% of the recipients who mark email as spam are pushed to do so because they cannot find a clear way to cancel their registration.

It is therefore essential that all sent emails have an unsubscription link that is clear, easy to see, and brings users to an equally clear and functional page. To learn more about this essential element of email marketing, we recommend our recent blog post where we explain why the unsubscription link conveys a brand’s transparency, reputation, and deliverability.

3. Rely on a professional infrastructure

Emails must be sent from a delivery system, i.e. a technological infrastructure that guarantees security and prevention against the pitfalls of phishingspam, and any other type of abuse by third parties.

MailUp is a perfect example: the delivery platform complies with the best security standards thanks to its certifications, and shared and dedicated IP addresses that are included in the most authoritative international whitelists and are constantly monitored to preserve and improve its delivery reputation; in addition, MailUp maintains close relations with the main providers and anti-spam organizations to favor email deliverability, adhering to feedback loop programs.

4. Keep your database clean

Quality is better than quantity: this is the basic assumption. Taking care to keep your database clean means managing delivery errors, user unsubscriptions and subscriptions in a timely manner.

An efficient process for managing bounces is crucial: email clients such as Gmail may even penalize senders if the number of bounces in a given amount of time reaches exaggerated levels. The volume related to incorrect addresses is one of the indicators used to determine a sender’s reputation, as it may be a clear sign of incorrect, if not illegal, contact acquisition. Additionally, the methodologies behind the anti-spam filters of the major ISPs have shifted from a simple content analysis to the real-time evaluation of the sender’s reputation: this is why properly managing bounces and removing invalid contacts before it is too late is of the utmost importance.

MailUp assists brands in this task by analyzing billions of records to identify and correct incorrect classifications. MailUp checks all outgoing email streams from servers to evaluate the number of hard bounces and percentage of emails sent by the customer, comparing it with the data history.

5. Comply with privacy laws

Any email marketing activity must be based on respect for a regulatory foundation: this means complying with the applicable legislation related to the processing of recipients’ personal data.

For more than a year there has been talk of a new European Privacy Policy that will provide European Union countries with a revised law on the processing of personal data for all the citizens of the old continent.

On January 10th, 2017, the Commission also submitted a proposal for a regulation on electronic communications supplementing the EU framework for data protection.

These interventions are aimed at strengthening the confidence and security in the single digital market, creating a fair balance between a high level of consumer protection and innovation opportunities for businesses.

At MailUp, we have followed the entry into force of the new Regulations through the trusted attorney Marco Maglio: you can find all the information you’re looking for in the dedicated section of our blog.

6. Be consistent with what you promised during registration

The relationship between brand and recipient lives in the grey area of expectations. If a person chose to receive a newsletter, it means he or she has considered it helpful and interesting to receive a certain type of content over time. For example, a new contact who has chosen to sign up for a newsletter about offers, flash sales, and promotions will certainly not find financial news regarding the brand’s corporate dimension at all interesting.

It is therefore critical to only send content that is relevant and consistent with what was promised during registration (i.e. in the registration form online, on the social page, or elsewhere).

As mentioned, this is a matter of expectations that, if not respected, will bring the recipient to unsubscribe and at worst, mark the email as spam.


1. Purchase or rent contact lists

This is one of the major strategic mistakes a brand that wants to develop an email marketing plan can make. Purchasing or renting “pre-packaged” databases is not only unprofitable, but is counterproductive.

The quantity of contacts in a database does not make a difference, the quality does: a database with millions of poor quality contacts is both damaging and useless. Quality is the only variable to consider when evaluating a database.

The starting point of any email marketing activity is the collection of email addresses that are obtained with the recipient’s consent, in his full willingness to receive communications. It is not only a best practice for converting emails into business opportunities, it is an ethical code that is bound to specific legal provisions, which we mentioned in number 5 of the do’s.

We have a blog post about the topic, where we explain in detail which risks are taken when you purchase email address packages.

2. Send email without authentication

Just like people traveling by air are required to show their passport and ticket, emails should also pass through authentication to prove what the email contains and where it comes from.

If the infrastructure and authentication are not set correctly, incoming email providers may have problems confirming the sender’s legitimacy. So here are the most authoritative protocols in the eyes of most email clients, which are responsible for evaluating and judging the message’s legitimacy:

  • SPF, which allows email services to check that incoming emails from a specific domain have actually been sent from an IP authorized by the sender.
  • DKIM (Domain Keys Identified Mail), this represents the next step in email authentication, as it not only validates the domain, but also the message’s content. To obtain validation, a cryptographic signature is added to the content that involves specific headers / parts of the message.
  • DMARC (Domain-Based Message Authentication, Reporting & Conformance), which leverages SPF and DKIM by giving brands that send emails the ability to specify how emails that do not pass validation should be handled. It also provides a framework for recipients to provide automated reports to senders with all the information needed to identify who is trying to falsify communications using their domain. With this system, not only can brands prevent the unauthorized use of their domains, but they can also monitor traffic and see if there are any valid IPs that have not been included in their SPF record.

3. Ignore inactive customers and standardize deliveries

The recipient database is not a monolithic block that the same communication should be sent to. Segmenting contacts is always recommended, and not only for personal data, but also for preferences and inclinations – also depending on the level of engagement: the least involved recipients (those who register low opening and click rates) should be separated from the most reactive ones.

Creating specific content for the low-engagement group also helps safeguard deliverability. This is because many email clients, most notably Gmail, seek clear evidence that the recipient wishes to receive the messages, and use this proof as decisive factors for cataloging the message either in the main inbox or in the spam folder. If email clients reason with inboxes, ISPs (Internet Service Providers) instead evaluate the goodness of the entire database. If the ratio between active and inactive users leans towards the latter, the ISP begins to deem that the sender is unreliable and of poor quality. It will then automatically relay its communications to the spam folder, in some cases going so far as to block its access to the mailbox altogether.

Therefore, in order to avoid negative consequences on deliverability levels, it is always best to monitor inactive users and envisage re-engagement strategies that include periodically checking and cleaning the database.

Just as important as segmentation based on involvement is the diversification of delivery lists: we strongly recommend that you have a different list for each type of email (promotional, transactional, newsletter, etc.).

4. Send emails sporadically

If your recipients forget who you are, they will be more apt to unsubscribe or click on the report spam button. This is why it is advisable to never send less than two monthly deliveries. If you are well below this level, we recommend making a well-scheduled delivery plan to reconnect with those recipients you haven’t sent email to for months with a re-engagement campaign, clearly specifying:

  • Who is the sender emailing the communication
  • Why the recipient is receiving the email
  • The reasons why the recipient should consider the messages relevant.

5. Isolate different systems

Creating a base for future tactical actions, each campaign’s data should be shared among all of a brand’s systems and applications (CRM, CMS, ERP, e-commerce, and business intelligence). Knowing, for example, which users clicked on a certain email lets you design a campaign targeted to them which will have a very high deliverability rate.

Filters also help profile recipients in a database or according to their actions. Triggered or automatic messages are sent upon the completion of an action and help build and maintain a personalized digital relationship with recipients.

To connect all the applications of a brand and fine-tune an integrated digital ecosystem, MailUp offers a vast integrations library.

6. Include HTML, JavaScript, Flash, or Activex forms

This kind of code does not work correctly with most email clients and can have different effects: from spam reporting to errors all the way up to a failure to display content. That’s why we always recommend using clean HTML code and nested tables.

To sum up

A successful campaign starts with successful delivery. Before sending, be sure to:

  • Have chosen a delivery infrastructure that is reliable and respectful of the major authentication protocols
  • Have adopted the double opt-in system for newsletter subscription
  • Have made the unsubscription process clear, visible, immediate, and intuitive
  • Have complied with the regulations regarding the processing of personal data
  • Have inserted a clear form that highlights all the benefits of subscribing
  • Send with regular frequency and respect the content promises you made when recipients registered
  • Be able to interpret and use statistical data in your campaign
  • Have your delivery platform communicate with other external systems.

And don’t forget that if you have a large volume of emails to send, you can take advantage of personalized consultancy: it’s called Delivery+, the service which, thanks to a wide range of advanced configurations and tailor-made consultancies, lets you maximize delivery rates and the return on investment of an email marketing strategy.

If you haven’t sent your first email campaign yet, try the MailUp platform free for 30 days.

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Andrea Serventi

I was born in 1986 in Milan, where I graduated in Modern Literature and started writing for online newspapers, magazines and TV news programs. Having now converted to marketing and the digital world, I am a Content Editor at MailUp: I read, listen, collect ideas, and write about what email marketing is and how to use it strategically.

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