Email deliverability

The effectiveness of your email campaigns relies heavily on email deliverability—the ability to successfully land in recipients’ inboxes. 

This article explores the key factors influencing email deliverability and provides insights into optimizing your email strategy for maximum reach and engagement.

What is the definition of email deliverability?

Email deliverability is your email’s ‘green card’ to reach the intended recipient’s inbox without being filtered out or blocked by various email service providers (ESPs) and spam filters. You could say it’s a bit like the email’s immigration system — with your email hoping to be the one that gets through.

Then we have email deliverability rate the statistic that quantifies your success (or failure) in getting past those email ‘border controls.’ This measure reflects the efficiency of your emails landing in the recipients’ inboxes and not being classified as spam or ending up in the junk folder.

A high deliverability rate is crucial for successful email campaigns, as it ensures that the intended audience receives and engages with your messages, leading to higher conversion rates and better business outcomes.

What influences email deliverability? 

Email deliverability depends on several factors, including the reputation of the sender’s domain and IP address (aka your email infrastructure), email content, adherence to email authentication protocols (such as SPF, DKIM, and DMARC), engagement metrics (like open and click-through rates), and the overall quality of the email list.

Email deliverability vs. inbox placement

Sometimes, you might come across another term instead of email deliverability – inbox placement. They’re two sides of the same coin, so you can use them interchangeably. 

Email deliverability vs. email delivery

Unlike inbox placement, this one’s a bit different from email deliverability. Email delivery is more about whether the recipient accepts your email. For example, if your email fails to land anywhere in the first place, it’s fair to say that email delivery was unsuccessful.

What is a good email deliverability rate?

Naturally, you’d aim for 100% email deliverability. But let’s be honest; the odds of reaching this top are slim. A good email deliverability rate is 95%, at least. 

Given its complexity, email deliverability is hard to measure manually. That’s why there are various 3rd party solutions, like Glockapps, that come to the rescue. 

How cares about your email deliverability rate? takes email deliverability seriously. We’ve implemented various measures to ensure our users’ emails have the best chance of reaching the recipients’ inboxes. 

Here are some of them:
Email verification: offers an Email Verifier tool that checks the validity of email addresses. This helps users filter out any invalid or risky addresses that might cause their email to bounce or trigger spam filters, ensuring their email lists are clean.
Domain and IP monitoring: continuously monitors the reputation of users’ sending domains and IP addresses. 
SPF, DKIM, and DMARC support: supports SPF, DKIM, and DMARC authentication protocols, helping verify the authenticity of email senders. This boosts deliverability by reducing the likelihood of emails being flagged as spam or spoofed.
Bounce handling:’s platform helps users maintain clean email lists and avoid bounces.
Email warm-up: offers an email warm-up service that prepares a user’s account for email sending and automatically improves the email deliverability rate with a consistent warm-up strategy. 
Delivery reports: keeps users informed with detailed reports on their email performance, including delivery rates, open rates, click-through rates, and bounce rates. These reports empower users to gauge their email campaigns’ effectiveness and make data-driven improvements. equips you with all the necessary tools to keep your cold outreach going, no matter the limits.
Try our Deliverability Check tools today for free.

What is bad email deliverability? 

Bad email deliverability means your emails don’t go right to the user’s inbox. Instead, they get bounced or end up in the spam folder. This is a sure sign you need to fix your email deliverability issues. 

What is an email bounce?

An email bounce, or bounce-back, is the boomerang of the email world. It’s when an email, instead of reaching the intended recipient, does a 180 and returns to the sender or an intermediary server with an error message. The sender typically receives a bounce-back message containing information about the reason for the failure.

There are two types of bounces: soft and hard. 

Soft bounce

An email returns as a soft bounce if:

  • the email size is too large
  • the recipient’s inbox is overfilled
  • the recipient’s server is down or temporarily offline
  • emails from the sender have been marked as spam by multiple recipients
  • the sender was blocked for being blacklisted
  • the sender’s email address (or the domain name) was blocked by the recipient’s server (or the recipient)

If you suspect soft bounces are caused by email rejections and blocks, the reason might be that:

  • you’re sending bulk emails from a free account, like a address (Gmail’s spam restrictions are pretty right!), causing a message block
  • the recipient’s server believes the email you’ve sent is spam, triggering SMTP Rejection/Error 554
  • your email address or IP is in the spam list, again leading to SMTP Rejection/Error 554

If you find yourself dealing with soft bounces, you need to first resolve the issue causing the bounce before trying to send your emails to the recipient again.

Hard bounce

A hard bounce, on the other hand, indicates a permanent issue preventing your email from reaching its destination. It happens when:

  • there’s a typo in the email address
  • the email address doesn’t exist at all, i.e., it’s invalid
  • the email address doesn’t exist anymore (maybe because the person has left the company)
  • the domain name doesn’t exist
  • the recipient’s email server was blocked
  • the sender’s email address has received too many soft bounces

To resolve the issue of hard bounces, you need to be sure all emails in your list are valid. That’s why you need to regularly verify your email list

Keep in mind that sometimes email filters can mistakenly classify legitimate emails as spam and reject them, which results in bounces. This can happen if the sender’s email is flagged for suspicious content or the sender’s domain or IP address is blacklisted.

What is an email blacklist?

An email blacklist, also known as a blocklist or DNSBL (Domain Name System Blacklist), is a list of email servers or domains tagged as sources of spam or other forms of email mischief. 

Email blacklists are used by ESPs, internet service providers, and other organizations that continuously monitor email traffic and collect data on servers or domains that exhibit spamming behavior or engage in other abusive practices. The goal of such monitoring is to protect their users from receiving unwanted or harmful emails.

Sometimes, being blacklisted can occur due to legitimate mistakes or misconfigurations. That’s why, as an email sender, your task is to keep a regular check on the email domain’s reputation. Think of it as checking your credit score, but for your emails. You can do this with the help of blacklist lookup tools such as MxToolbox or DNS Checker.

In case you’ve found your IP address or domain in any of the blacklists, you need to address the issue that led to the blacklisting. This could involve resolving security vulnerabilities, stopping any spamming activities, or improving email practices. Otherwise, your reputation and email deliverability are in danger. 

Read more about blacklists and how to avoid them

How to improve email deliverability

Here are the basic tips on how to improve email deliverability:

1. Maintain a healthy email list

Regularly clean and update your email list by removing inactive or invalid email addresses. Use confirmed opt-in or double opt-in methods to ensure recipients have explicitly requested to receive emails from you.

2. Respect recipients’ preferences

Unsubscribing should be as easy as subscribing. So honor unsubscribe requests promptly, provide clear instructions on how to opt-out, and remove the unsubscribed email addresses from your list.

3. Follow email sending best practices

Use reputable ESPs that have good deliverability rates. Authenticate your emails with SPF, DKIM, and DMARC records. And remember to warm up your email account before sending out bulk email campaigns.

4. Ensure proper email infrastructure

If your IP address is shared with others (i.e., used by multiple senders), there’s always a possibility they might be sending unsolicited emails from the same IP address. So if you’re a high-volume sender, consider using a dedicated IP address, one that is only used by a single sender.  

5. Avoid spam triggers

Make sure your email content doesn’t raise any spammy red flags. Use meaningful subject lines, steer clear of excessive capital letters or exclamation marks, and refrain from using spam-related keywords.

6. Monitor email engagement metrics

Keep a close eye on your open rates, click-through rates, and spam complaint rates. If you’re seeing high engagement and low complaints, you’re hitting the right notes!

7. Manage email bounces

Keep tabs on your bounce rates. It’s okay to retry soft bounces (temporary delivery failures), but hard bounces (permanent delivery failures) warrant immediate removal from your email list.

8. Respond to abuse reports

Actively investigate and address any abuse reports or complaints received from recipients or ESPs. Promptly take appropriate actions to rectify any issues causing the complaints.

→ Visit Sales Cheats – a first-aid solution for your business growth – to learn more about spam complaints and how to reduce them.

9. Keep a watch on your sender reputation

Monitor your sender reputation by using reliable tools or services to help you keep an eye on email deliverability metrics and blacklists.

10. Build positive sender relationships

Cultivate strong relationships with your recipients by consistently delivering valuable and relevant content. Encourage recipients to add you to their contacts or whitelist your email address to ensure smoother deliverability.

Recipe of good email deliverability

And here you have it!

Understanding and prioritizing email deliverability is a must if you want your email outreach to score a perfect ten. By focusing on factors such as sender reputation, email authentication, and engagement metrics, businesses can enhance their chances of reaching the intended audience and achieving higher open and click-through rates.

Now it’s time to put this knowledge into practice. Take the insights from’s research-based email deliverability guide and weave them into your strategies to ensure your emails land in the recipients’ inboxes and make a lasting impact on both potential and existing customers.

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