The deliverability of an email is simply the set of steps and processes that are needed to deliver your email to someone else’s inbox. 

Some of the factors that can affect email deliverability are as follows: 

• Sender Reputation

Your email sender reputation is one of the main factors that affects the deliverability of your cold emails. It is a score assigned by the recipient’s ESP to the sender of the email. Sender reputation is a combination of two factors – domain reputation and IP reputation.

An ESP will be more likely to deliver your emails to the main inbox of a recipient on their network if your sender reputation is good. If your reputation falls below a certain threshold, your emails will either be blocked outright or delivered to the spam folder of the recipient. 

Some of the factors that determine sender reputation are–

• The level of engagement on previous emails sent from your email address
• The quality of the email content 
• The quality of your contact list
• The bounce rate of your emails

• Volume Trends

The volume of cold emails you send on a regular basis will have a huge impact on your email deliverability. For instance, if you start sending out hundreds of emails per day from a new domain, the ESP will immediately flag you as a spammer. This is an easy way to ruin your domain reputation.

To prevent this from happening, you will first need to warm up your new email address by sending emails to friends, colleagues, and existing clients – anyone who will almost certainly engage with the email by reading it, replying to it, forwarding it, etc. 

You can then slowly increase the volume of emails sent per day, per week, and so forth. For instance, you can send out less than 50 cold emails the first week, about 85 the second week, 100 emails the third week and so on, until your cold emailing campaign is generating the desired results. 

• Spam Trigger Words

There are some words and symbols that are usually associated with spam, both by email recipients as well as by ESPs. 

If your cold email is full of these ‘spam trigger words’, then there is a high risk that it will end up in the spam folder. 

So-called ‘salesy’ language and overly promotional words in your email content or subject line can trigger the ESP’s spam alerts. These words and symbols include:

• FREE
• Exclusive offer!!
• Dollar signs ($$$)
• Too many words in all-caps
• BUY NOW!!!
• Lots of exclamation points
• Too many emojis

If your cold email contains an excess of these elements – either all of them or any one – then it will attract the attention of the ESP servers, increasing the likelihood of your email being relegated to the spam folder. 

• Abuse Reports

The action taken by a recipient after they receive a cold email from you will impact the deliverability of your future emails. 

For instance, if a prospect marks one of your cold emails as spam, then the ESP will consider this an abuse report against you, as the sender of that email. 

Such abuse reports help Gmail, Outlook, and other ESPs identify spam, so as to keep their customers’ inboxes clean. But if too many of your recipients mark your cold emails as spam, then the ESP will flag you as a questionable sender. 

As a result, all your future emails will either be blocked from delivery or delivered directly to the spam folder. 

Therefore, you must ensure that no more than 0.5 percent of your cold emails end up marked as spam, in any given month. To minimize abuse reports, you should only send cold emails that are highly personalized, relevant, and well-formatted. 

• Spam Traps

A spam trap is an email address that is owned by the ESP, rather than belonging to a real person. 

These email addresses are often used to lure spammers, who send out bulk emails with little regard for how the individual recipient is responding to their message. 

Spam traps can be of two types:

• Pristine spam trap: A new email address created by the ESP for the specific purpose of functioning as a spam trap. This email has never belonged to a real user.

• Recycled spam trap: This email address used to belong to a real person, but was abandoned some time ago. After lying inactive and unused for a year or more, it was reclaimed by the ESP and put to use as a spam trap. 

This spam trap email address is then left on various web pages and discussion forums, in order to entrap spammers who make use of web crawlers to harvest email addresses and sell them for money. 

This is why purchased email lists often contain a disproportionate number of spam traps. Because most web crawlers cannot distinguish between spam traps and genuine email addresses belonging to real people. 

Frequently sending cold emails to spam trap accounts will get your domain flagged by the ESP, and ruin your email deliverability. 

This is why you should always monitor your contact list and remove dormant, unengaged, and unresponsive email addresses from time to time. 

• ESP Blacklists

Ending up on an email blacklist is perhaps the fastest way to trash your cold email deliverability. A blacklist is simply a database of IP addresses and sender domains that have been flagged as suspicious for sending spam emails. It acts as a filter that will help determine whether or not your email will end up in the inbox of your intended recipient. 

Gmail, Yahoo, Outlook, and other major email service providers all maintain their own blacklists. Spamcop, Composite Blocking List (CBL), and Exploits Block List (XBL) are some of the largest and most important email blacklists that are publicly available. 

If your IP ends up in any one of these, you’re in trouble. You’ll have to appeal to the blacklisting organization to get removed from the blacklist, which is an arduous (and often futile) process.  

Some tools that can help you check your blacklist status are:

• MXToolBox
• Whatismyip’s blacklist checker
• MultiRBL blocklist lookup tool

You can avoid ending up on email blacklists by only sending cold emails that are valuable, well-formatted, relevant, and of the highest quality. Do not use misleading subject lines to try and get more engagement, and avoid spammy, overly salesy language as far as possible.  

• Email Components 

The component parts of your cold email can help determine its deliverability. Hence, you must be very careful about what you include in the email content, before clicking the send button.

Some of the things you should look out for are:

• Text-to-Image Ratio

Typically, ESPs like emails that have more text than images. This is because too many images and gifs are often the sign of a spammy, promotional email. 

Therefore, you should maintain a text-to-image ratio of 60:40, at the very least. Ideally, you should have no more than one or two images in your email body, especially if you’re just warming up a new domain. 

Moreover, you might want to limit your image size to 100KB or less, when sending out cold emails.

For better deliverability, try and design your cold emails in a way that they would make sense even if the images were taken out. 

• Links and Attachments

Overloading your cold email with tons of links and attachments is a sure way to get caught by spam filters. Experts recommend having no more than two links in a cold email, including the signature. 

When you send out a cold email, you’re trying to establish communication with someone you don’t know very well, if at all. Naturally, the recipient might view an email from a stranger with some level of suspicion. 

This is further exacerbated if the email asks them to click on tons of links or open multiple attachments. Spammers and hackers have, in the past, used malicious links and email attachments to infect devices with malware. 

So, ESPs automatically consider these elements to be a red flag, and might block an email that has too many of them, especially if it is from an unknown sender.