Email marketing deliverability

Deliverability is a crucial term in email marketing, as it determines how many of your mass emails successfully reach your recipients’ inboxes.

In other words, good deliverability ensures your subscribers receive your messages and that your email marketing campaign doesn’t get lost due to spam or email filters.

Below, we will explain what deliverability is, how this concept works when sending mass emails, and how to improve it to boost the success of your email marketing campaigns.

What is email marketing deliverability?

Deliverability in email marketing refers to the ability of your emails to successfully reach your subscribers’ inboxes, rather than ending up in the spam folder or other secondary tabs.

This concept measures the percentage of sent emails that are actually delivered correctly to recipients.

Simply put, if you send 100 emails and 90 reach the users’ main inbox, we could say you have a 90% deliverability rate.

The standard formula to calculate this percentage is:

deliverability rate = (delivered emails / sent emails) × 100

It is important not to confuse deliverability with the “open rate” or the “click-through rate“.

Deliverability only evaluates the delivery of the email (whether the message reaches the inbox), without considering if the user later opens or interacts with it.

Now that we have clarified what deliverability means, let’s see why achieving a high rate for your email campaigns is so important.

Why is deliverability important?

Deliverability is vital because an email marketing campaign is useless if your emails don’t reach the recipients.

No matter how well-designed your newsletters are or how attractive your offers may be, if they end up in spam or are not delivered, your efforts won’t generate results.

This translates into lost sales opportunities and a wasted investment of time and resources.

Furthermore, poor deliverability can damage your brand reputation.

When subscribers provide their email address, they are placing their trust in your company.

If your emails fail to reach their inbox, that trust is compromised.

Consequently, poor deliverability affects your business’s credibility and even your revenue, as fewer viewed emails mean fewer potential conversions.

In short, ensuring good deliverability is fundamental to the success of any email marketing strategy: it guarantees that the message reaches the audience and maximizes the return on investment of your campaigns.

How does email deliverability work?

Email deliverability works by taking multiple technical and behavioral factors into account.

Several actors are involved in each sent email (your sender domain, the emailing platform, the email providers’ filters, and the recipients themselves) that determine whether a message will reach the inbox or be filtered.

Essentially, deliverability is the result of a combination of key elements, including:

3 Sender reputation:

The reputation of your sending domain and IP heavily influences deliverability.

If you have historically sent high-quality emails with low spam rates, email providers (like Gmail, Outlook, Yahoo, etc.) will trust your messages more.

Conversely, if your domain or IP address is listed on blacklists or has generated many spam complaints, your emails will struggle to reach their destination.

· Contact list quality:

The hygiene of your database is another crucial factor.

Sending emails to invalid or old addresses, or to users who never interact, harms deliverability because it increases the bounce rate and can signal to providers that you are not managing your mailing lists carefully.

Maintaining a clean list (without non-existent or inactive contacts) ensures your messages are only sent to real and interested recipients.

· Subscriber interaction:

The behavior of your readers also affects deliverability.

If users frequently open, read, and click on your emails, email providers will interpret your messages as relevant and desired, improving your ability to reach the main inbox.

On the other hand, if many subscribers mark your emails as spam, delete them without reading, or never interact, anti-spam filters will understand your content is unwanted and could relegate it out of the inbox in future sends.

· Email content and anti-spam filters:

What and how you communicate in your emails influences their delivery.

An overloaded design, containing only images or using excessive spam trigger words (like “free”, “offer”, “urgent”) can trigger anti-spam filters.

Similarly, poor HTML formatting or suspicious links are a red flag for filters.

Email services analyze elements such as the subject line, message body, and formatting for signs of spam or phishing.

If the content seems suspicious or inappropriate, the email will likely end up in the junk folder.

· Authentication and technical setup:

Technical aspects such as the setup of SPF, DKIM, and DMARC – email authentication protocols – have a direct impact on deliverability.

These configurations tell the recipient’s provider that your emails truly come from you (from your legitimate domain) and not from an impostor.

For example, a correctly configured SPF indicates which servers are authorized to send on behalf of your domain, and DKIM adds a digital signature to your messages.

If you don’t have these measures in place, many servers might reject your emails or mark them as suspicious.

Relying on an email marketing platform that properly manages these authentications significantly improves your delivery chances.

In summary, deliverability works as a delicate balance between reputation, contact list quality, the content you send, and the technology backing your emails.

Understanding these factors will help you identify what might be failing if your emails aren’t arriving and, above all, how to fix it.

How to improve deliverability in your email marketing campaigns?

Achieving good deliverability is not a matter of luck, but of consistently applying a series of best practices.

If you are wondering how you can increase that inbox delivery rate, below we review several key tips.

By following these recommendations, your mass mailing campaigns will have a much higher chance of landing in the inbox of your subscribers:

· Use a reliable and high-quality email marketing platform

The first step to improving your deliverability is ensuring you send your emails through a reliable email marketing tool.

Professional platforms (like Mailrelay, for example) have optimized infrastructure, servers with a good reputation, and strict anti-spam policies.

This means that by using a reputable service, your messages start with an advantage in being accepted by email providers.

Additionally, these platforms usually handle complex technical aspects – such as SPF/DKIM authentication or blacklist monitoring – so you don’t have to worry about them.

In short, rely on a good bulk emailing service that takes care of the deliverability of your campaigns from a technical standpoint.

· Implement double opt-in on your subscription forms

An effective way to protect your deliverability is by building a list of contacts genuinely interested in your content.

To achieve this, use double opt-in for subscriptions: this method requires the user to confirm their email by clicking a confirmation link sent to their inbox after registering.

Why does this help?

Because it ensures that every email address in your database belongs to an active person willing to receive your messages.

With double opt-in, you avoid fake or incorrect contacts and guarantee higher-quality subscribers, reducing future spam complaints and improving the performance of your campaigns.

· Don’t buy email lists or send emails without permission

It may sound tempting to try to quickly grow your list by purchasing a database or adding contacts who haven’t given their consent, but it is a bad practice that severely harms deliverability.

Contacts who haven’t requested your emails are highly likely to ignore them, delete them, or mark them as spam.

The latter, in particular, is fatal to your sender reputation.

Furthermore, in many countries, sending unsolicited emails violates data protection regulations.

Therefore, build your list organically: gather subscribers through forms on your website, events, social media, or other channels where they voluntarily express their interest.

Quality is better than quantity when it comes to email marketing.

· Keep your subscriber list clean and updated

Email list hygiene deserves constant attention.

Over time, it is normal for certain contacts to stop interacting or for some email addresses to cease to exist (due to job changes, new providers, etc.).

That is why it is important to regularly clean up your database.

Remove or try to re-engage subscribers who have been inactive for a long time, and of course, delete addresses that generate hard bounces because they don’t exist.

Maintaining a clean list reduces the proportion of emails that never arrive (due to full or non-existent inboxes) and shows ISPs that your sending practices are responsible.

Consequently, your deliverability will improve because you will be sending emails to an active and genuinely interested audience.

· Take care of your email content and formatting

The content you send is your cover letter to both spam filters and your subscribers.

To optimize deliverability, send high-quality, relevant content to your audience.

Avoid overusing words considered spam or flashy symbols in the subject line (like ALL CAPS or exclamation marks such as “BUY NOW!!”), as they can trigger alerts.

Likewise, balance your use of text and images – an email that is just one large image, with hardly any text, can be suspicious to filters.

Ensure your message is well-formatted, with clean HTML if you use it, and include descriptive alt text for your images.

A clean, professional, and useful email is more likely to pass anti-spam filters and also capture the positive attention of your subscribers (which, in turn, improves future deliverability).

· Segment your campaigns and personalize the message

Not all your subscribers are the same, so sending everyone the same message can result in a lack of interest from many.

By segmenting your list into more specific groups (for example, by interests, geographic location, stage in the buying cycle, etc.), you can personalize the content and send truly relevant information to each segment.

Why does this improve deliverability?

Because recipients get emails they are interested in, making it more likely they will open and interact with them.

Higher engagement (opens, clicks, replies) indicates to Gmail, Yahoo!, and other providers that your emails are well-received, reinforcing your reputation as a legitimate sender.

Consequently, segmenting and personalizing is a winning strategy: it enhances the user experience and boosts your delivery metrics.

· Send with the right frequency and consistency

Consistency in your sending frequency also plays a role in deliverability.

Try not to go from 0 to 100 abruptly; that is, avoid sending very few emails for weeks and suddenly sending a massive volume all at once, as those unusual spikes can trigger spam alerts.

It is advisable to maintain a regular sending frequency (for instance, a weekly or monthly newsletter, depending on your strategy) so that both your subscribers and email servers “expect” your messages.

If you need to increase your sending volume (for example, during a special promotion), do so gradually or in stages.

This process, known as warming up (IP or domain warmup), helps email providers view your sending growth as normal behavior.

In summary, send emails in a steady and periodic manner, as extreme irregularity can damage your reputation and, along with it, your deliverability.

· Configure authentication: SPF, DKIM (and DMARC)

Lastly, don’t neglect the technical aspects backing your sends.

Configuring SPF and DKIM records on your domain is essential to improve the deliverability of your emails.

These protocols serve to validate that you are who you claim to be when sending an email: SPF specifies which servers are authorized to send emails from your domain, while DKIM adds a digital signature to each message to confirm it hasn’t been altered and comes from a reliable source.

Implementing DMARC as well can give you an extra layer of protection, instructing receivers on what to do if a message fails SPF/DKIM checks (for example, rejecting it or sending it to spam).

By having these authentications correctly configured, your emails will build more trust in the eyes of Gmail, Outlook, and others.

Many email marketing services guide you through this process.

Taking the time to activate SPF, DKIM, and DMARC directly results in a higher delivery rate.

What is the best email marketing tool to improve deliverability?

Choosing the right platform can make a huge difference in the deliverability of your campaigns.

The best email marketing tool will be the one that offers a solid infrastructure, strict anti-spam policies, and support to implement sending best practices.

Mailrelay, for example, stands out as a platform geared towards maximizing deliverability: it offers highly reputable servers, the ability to easily configure SPF/DKIM, and an expert support team to advise you at all times.

Furthermore, Mailrelay provides the largest free account on the market (up to 80,000 monthly emails to 20,000 subscribers) and human technical support for all accounts, even the free one.

These advantages allow you to improve your deliverability with zero initial investment, as you can send mass campaigns, monitor your results, and clean your lists with professional help.

Ultimately, if you want to guarantee your emails reach the inbox, it’s crucial to rely on a trustworthy email marketing tool like Mailrelay, which combines excellent technical features with expert guidance.

This way, you can focus on creating great content while the platform ensures your messages reach your customers!