16 May 2022

Email Deliverability: Best Practices You Should Know

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Table of contents
  1. 1. Create a subdomain
  2. 2. Keep your DNS records in check
  3. 3. Warm up your mailbox
  4. 4. Keep your email list clean
  5. 5. Steer clear of the spam folder
  6. Wrapping up
1. Create a subdomain

To ensure your email marketing campaigns are not a waste of time and resources, you have to think about email deliverability. It’s a probability of your email messages landing directly in the prospect’s inboxes. The higher this probability is, the better your deliverability gets. 

Keeping email deliverability at good rates is not a piece of cake, so five tips will help you build and maintain it. 

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1. Create a subdomain

Domain reputation is fragile — it is challenging to build and maintain at high rates, yet it is very easy to lose in no time. So it is essential not to overload it with much pressure. It’s not necessary your prospects will like the content you’re sending to them, even though they know that they’ll be getting your emails from time to time. There’s always the chance they may unsubscribe, mark your emails as spam, or delete the email. If they are flagged as spam or deleted, it will influence your domain health, IP, and email address reputation in a bad way. 

You are using your email account to send different types of emails: both promotional and transactional. And transactional ones are significant for your prospects because they are sent every time users interact with your website. 

And imagine if you have all of that pressure of transactional and promotional email campaigns on your single domain. 

So, the best solution here is to create a subdomain for your promotional emails. You can run A/B testing and send emails in bulk without worrying about your transactional emails. Your campaigns just simply won’t clash with each other. 

A subdomain is also very helpful in building trust with your audience. Users tend to trust subdomains over time.

A subdomain may come in handy if you send so many emails that the number of email addresses is higher than the main domain can handle without harming its reputation and engagement levels. 

What does a subdomain look like? Let’s assume your company domain is, and your subdomain may be Remember that it should be consistent with your original domain, even with some prefixes added. Creating a separate subdomain for every sales channel you're trying out is highly recommended. 

2. Keep your DNS records in check

The modern digital world is full of spammers and fishers attempting to steal senders' identities to discredit them. And, of course, you don’t want your high sender reputation and trust with internet service providers to be destroyed by one cybercriminal. And here comes email authentication.

Email authentication can be defined as protocols that help mailbox and email service providers distinguish between legitimate and malicious emails. Having identity theft protection installed, you can be sure that all emails sent by someone on your behalf will never reach your recipients' inboxes. Still, your messages will always arrive at their destination folder.

Moreover, there are other reasons email authentication is crucial for your account:

  • it helps improve email deliverability. If receiving servers have problems authenticating incoming emails, they would better terminate all interactions with your domain and mark it as suspicious. The faster email service providers can identify your message, the higher your engagement and inbox placement rate will grow;
  • it increases your brand reputation. To be recognized by your target audience, you don’t have to neglect security measures. Nowadays, there are a lot of brands, and it is a matter of particular attention for email service providers whether the domains are authenticated and generate malicious activity;
  • it raises brand awareness. Email authentication protocols let you establish yourself as a certified sender. For instance, thanks to the BIMI protocol, you can display your brand's logo in your prospect’s inboxes before they open your email. It makes your company more recognizable. An email header analyzer tool can help you cross-check your domain's email security compliances and read your email headers in a parsed human-readable format.

So, as we mentioned before, email authentication comprises email safety protocols. They are:

  • SPF (Sender Policy Framework). It certifies that messages were sent by a legitimate sender or a third-party service approved by the legitimate sender and provides guidelines on dealing with emails that allegedly came from your domain but aren’t mentioned on the list of authorized domains or services;
  • DKIM. It attaches an encrypted header to every email sent by you. Only receiving servers can see this signature and use it to check your DNS records, validating your sender identity and deeming the message’s content to be safe;
  • DMARC. It generates reports on SPF and DKIM performance, letting you track your delivery status and see how many emails fail or pass the authentication check;
  • BIMI. Displaying your brand’s logo in the recipient’s inbox makes it easier to identify you and prove that a credible business domain sent the message.

The protocols mentioned above are based on DNS records that comply with them. The abbreviation DNS stands for Domain Name System. Its principal function is to translate different domain names to IP addresses that correspond to them. 

You add those records by creating a text string that contains particular modifiers and mechanisms, saving it as a TXT file, accessing your DNS settings, and then publishing it in the DNS file zone of your domain. We know it may sound a bit complicated, so, as a newbie to the email authentication, what you can do is:

  • count on your email service provider. Some services, like Gmail, may generate SPF and DKIM records automatically. If you’re a casual sender, then you can go with that. However, if you want to drill into your delivery status and data, you would need to make some changes;
  • contact professional to work on your DNS records. Tell him your email marketing needs, and he will set them up so they will work properly. You also have to reach out to an experienced person to avoid creating a wrong or duplicated record;
  • try DNS record generators. You can find a service that will generate a text string with all the necessary information about your domain instead of you.

3. Warm up your mailbox

Adding DNS records is only a half. Considering that you start with a new mailbox and domain, you can’t just start sending lots of emails.

Every time you create a new account to proceed to email marketing campaigns, the system sees it as a new one. It has a neutral reputation that can change in a minute if you’re too active and trying to reach out to many prospects. 

To ensure your account is trustworthy and reputable, email marketing warmup must be addressed. Simply put, it is the process of sending emails from a new account, slowly starting with a small number of messages and gradually increasing the limits. You create a good reputation for your domain and IP address by doing so.

You shouldn’t use your newly created email address for sending a bunch of messages immediately because each ESP has its sending limit. If you exhaust the whole offered limit right away, the provider will consider your mailing campaign as spam, putting you in danger of your account being blocked. And it will damage your sender reputation, leading to a lower deliverability rate, and, eventually, to an ineffective email marketing campaign. So, send out fewer packs before increasing to the available limit. 

So, how to warm up your domain?

There are two possible approaches: you can do it either manually or automatically. You can resort to the email deliverability software that can not only check your domain reputation and warm it up, but also constantly maintain deliverability rates at a high level. In any case, you have to remember that the warm-up process takes time. We can’t state a specific period you’ll likely need, although generally, it continues for about three months. 

If you decide to opt for the manual email warmup, here are some tips that will help you:

  • set your daily limits. Define a particular number of emails for a day. It can be from 5 to 10 messages daily. Be careful and use only warm email addresses, like your long-term colleagues or customers, so that they will interact with them. They need to open your emails, mark them with a star, remove them from the Spam folder, flag them as ‘not spam’ and reply to you with a few phrases;
  • make up a schedule. Choose a specific time slot for sending your emails. At the very beginning, you’ll need to send emails every day. It ensures that internet service providers identify your account as an active one;
  • constantly monitor. Continue sending a few emails to those trusted warm email addresses for two weeks. Then run a mailbox audit. Should your delivery and open rates be good, and the level of bounces is low, you can increase your sending volume a little bit. For example, if you started with five emails a day, now you can proceed to 10.

4. Keep your email list clean

An email list is a group of email addresses that service providers gather through different sources, like blogs, websites, or other subscriptions. Once you’ve composed your mailing list, you may use it to send the emails to the addresses in the list.

You may have already heard of pre-composed email lists you can buy on the web. We warn you: in any case, don’t do it. Otherwise, you put your email deliverability at risk because most emails aren’t even tested. So, dedicate your time and effort.

Compiling a list of emails is a long process. You have to go through prospect data, fish out email addresses, and verify them. Get users’ consent, which is a must! And then you’re ready to go.

However, what happens when you’ve managed to build a massive list of verified email addresses? You think that all the job is done and you don’t have to check this database any time soon. Well, the situation is quite the opposite. Otherwise, all your efforts will go in vain. Any data changes and expires way faster than you may have thought. A regular list clean-up is exactly what you need to keep your contact list up-to-date and your email deliverability at high rates.

But what happens when you don’t clean your list:

  • your bounces grow. When your email lands in a non-valid or deleted inbox, you receive more hard bounces, alerting email service providers and reducing your sending reputation;
  • you get labeled as spam. If you keep sending emails to people who no longer want them, it ends with your messages flagged as spammy, increasing your risk of getting blacklisted;
  • you come off as annoying. Nothing is more frustrating than a clueless sender. Neither email networks nor your prospects would forgive sending emails to the wrong person for the wrong reason.

So, make sure your list is always clean and ready for the outreach — you’ll be sure that your emails land directly in the relevant inboxes.

5. Steer clear of the spam folder

One of the biggest problems for any email sender is when you create an email and it is being treated as spam by receiving servers and getting redirected to spam folders instead of user inboxes. It can make your campaigns almost invisible and even incapacitate your domain. 

If you don’t take action to prevent the emails from going to spam, email service providers will start labeling your messages as spam by default. Thus, the percentage of emails sent to spam will only increase, dragging your sender score down. As a result, your reputation will be destroyed, and your deliverability will significantly drop. 

You may never get to know why your email was considered spam. Although your message can possess specific criteria that make algorithms move it to the spam folder immediately:

  1. You use spammy words in either the email content or its subject lines.
  2. You turn to shared IP addresses.
  3. You send bulk emails without having set up the DNS records. 
  4. You use purchased contact databases. 
  5. You send bulk emails without prior warming up your mailbox. 
  6. Your sender score is low, and the bounce rate is high.
  7. You send bulk emails and don't allow readers to opt out. 
  8. You send emails with images, attachments, and links. 

Without making sure that your emails are correctly delivered, meaning you manage to avoid the spam folder, there is no point in sending emails. 

Wrapping up

Many email marketing strategies are created to help you succeed with your mailing campaigns. Nevertheless, email deliverability practices are among the most effective approaches to keeping your email engagement rates up to the mark.

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gurpreet singh 1 year ago
This is a really interesting read. I was actually looking for subdomain tips and I find them useful. Thanks for sharing
Hanna Kuznietsova 1 year ago
Thank you. We're glad you find this useful ?
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