Cold Email Deliverability COMPLETE Guide (2023)

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How to deliver cold emails to inbox guide

Cold Email Deliverability COMPLETE Guide (2023)

How many hours did it take our team to write this Complete Cold Email Deliverability Guide? Something like 15 years. Yes! The ability to deliver cold emails to your lists’ inbox folders takes a lot of experience to develop. It literally requires years of endless attempts, tailored processes, B2B sales strategy development, trial & errors, ever-changing tactics, and millions of campaigns to learn how to really deliver emails. Deep understanding of the subject of bulk emailing, sending servers, sending IPs, SMTP, and postal, industry players, and new spam algorithms are absolutely necessary to master the art of cold email marketing.
This is why we are so pleased to deliver to you our conclusions, cold-email tips and tactics, and bulk emailing strategies. Enjoy

Table of content

What is The Main Challenge in Cold Emailing?

The main challenge you have to figure out when applying cold-ema practices is deliverability. That is to say, your ability to deliver emails to your recipients’ inbox folders while avoiding spam filters. In other words, if your deliverability is in good shape, your ability to reach out to new audiences by means of cold-emails, is high.
How Spam Filters Work?
You should be aware of how email spam filters work and how to validate your sending servers to make your campaigns delivered. Internet Service Providers (ISPs) work to detect bot-made emails and remove them from priority inboxes or send them directly to spam folders. When mass mailing is sent to a high volume of recipients and is coming from a new IP address, it may raise a red flag. This means that if you want your emails to go to your recipients’ inboxes without fail, you must first establish a good reputation in the eyes of the ISPs. In simple words make your emails human.
This sender reputation is also called email-validation.

How does cold email deliverability sender reputation work?

Cold email deliverability is another way to describe your email campaigns’ ability to reach the inbox. Email delvierability heavily depends on sender reputation which is a rating given by each mailbox provider or ISP (Internet Service Provider such as Gmail, Yahoo, Hotmail). The sender reputation consists of the level of trust you – the sender – receive from each ISP. That quality is determined in relation to the campaign-history of the IP, the domain from which the emails are sent, the URLs that the emails link to, the content of the emails and many other factors.

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How can email deliverability be REALLY improved?

First and foremost, email deliverability can be improved by bettering the reputation of the server or IP that is used to send your emails. However, let’s face it, if you are in the business of cold emails, chances are that sooner or later your IP will be flagged. Someone, who didn’t ask to get your campaigns, will report your emails. 
Here are some of the common practices and why they don’t really work with bulk cold emails:
1. Conventional email platforms shared IPs.
This is probably the first thing you tried. Signing up to Activecampaign, Sendinblue, MailerLite or ConvertKit and using their shared IPs which are undoubtedly strong and reliable. However, apart from the high costs that are associated with using email marketing platforms for mass cold campaigns, once the system realizes that you use their servers for “cold-type” campaigns, i.e. you upload a large database and present low opening rates, they will most likely suspend your account. Why? For the same reason their shared IP rap is in good shape: they don’t allow cold emails.  
2. Dedicated IPs and dedicated servers like Postmark
After you’ve realized that you can’t really use shared IPs for cold emails, you found out (or you were told by a sales-rep, that you should have your own dedicated IP. Sendinblue will let you know that very fast, Activecampaign will introduce you to Postmark– an email delivery service that they recently acquired. Other platforms will send you to Contabo or DigitalOcean
The costs of those dedicated IPs will be exceedingly high and the fact that none of them will deliver or inbox any bulk emailing without a proper warm-up, make this option unjustifiable and not recommended. Moreover, just like the shared IP option, if you will get hard-bounces or complaints, or if some of your cold emails will be flagged, you can be sure that server-providers like Postmark and Contabo WILL suspend your account. That’s a 100% guarantee.  

Then what are the best email deliverability practices to follow?

Based on years of experience, tons of trial & error, and millions of campaigns, we concluded the following: 
The best strategy for cold emails and bulk emailing is:
  • Use a Warm-Up + Bulk emailing Tool
    • Rotating IPs:
      At least one IP per 1,500 emails. That means that for each campaign of 200,000 emails, you should have around 129 different IP addresses, all warmed up with a high and clean reputation.
    • One sending domain per approx. 3,000 email sending. The domains will be rotating. You should get around 330 different domains for 1 million emails.
    • Warm up with warming profiles or a manual warm up. Around 25 warm up profiles per 2,000,000 emails. 
    • Verification of your email lists. Clean all false emails and eliminate any potential hard bounce. 
    • Only purchase high quality lists.
As far as the content of your emails goes, remember: the more relevant your emails will be to the recipients, the higher the chances you will not be blocked by spam filters.
Here are some high-performing strategies to consider:
– Choose a well engaging subject line and preview text 
– Segmentation (!)
– Segment your lists so you can tailor more personalized messages. 
– Keep an engaging signature
– Don’t link to flagged sites 
– Remove spammy words 
– Add real worth to the reader. The readers should find your emails useful by just reading them. 

What is the best service to use when sending cold bulk emails?

While email marketing platforms like Activecampaign, Sendinblue or MailerLite will not allow to use their shared IP for cold bulk emails, and while servers such as Contabo or Postmark will suspend your account if it is suspected or flagged, your best option to inbox your cold emails is to build a system of warmed up rotating IPs and domains, and keep your cold email practices meticulously clean and professional.

How can I send 10K cold emails per day?

We recommend the following practice to get the best deliverability when sending 10K cold emails per day:
* 4-5 rotating IPs
* 3 Rotating sending domains
* Warm up your servers
Read here a full comparison of the best bulk email platforms 

How to check an email delivery campaign’s reputation?

1. Check hard bounce rates.
An email bounces when the ISP (i.e. Gmail, Yahoo etc.) or the server is returning the email and not delivering it. Hard bounce usually happens when the address is incorrect or when there is another permanent issue with the address. Hard bounces are bad for your sender’s reputation and you should avoid them by verifying all addresses before emailing them.  
2. Check complaint’s rates 
3. Check your opening performance and your campaigns’ stats regularly 
If your open rate is sufficient, you are not being sent to the spam folder and this is great news. If your click rate is still low, it means that people open your emails but don’t act. Perhaps something with the content should be improved or maybe your messages should be more segmented and relevant.
If there are no bounces and no spam but low open rates, perhaps your subject line is not strong enough. There is also a possibility that your emails are simply not compelling enough to the audience. Try to learn your audience, see what they really need, and use emails to communicate with them at a level that is valuable to them.
4. Send tests to multiple email addresses and check the delivery tabs.

What is the difference between email soft bounce and hard bounce?

Email soft bounce happens when an email makes it to the destination server but is not delivered to the recipient’s inbox. It could be that the inbox is full or inactive. Soft bounce does not harm your sender reputation. Hard bounces of your emails on the other hand, are bad for your sender rap. They indicate an error in the address and that the email has failed to be delivered because of a permanent reason. Make sure you clean & verify your email lists before sending cold campaigns.

Which is the best tool to check email deliverability score?

ZeroBounce Score™ is a tool that uses artificial intelligence to assess how your subscribers may interact with your cold emails. By detecting email activity levels, the tool can reveal how likely you are to reach a real person on the other end of an email. The scores it returns range from 0 to 10, with 10 being the highest quality rating.

Is there a way to boost email reputation?

The strategy that Omni’s email marketers have developed to boost email reputation consists of:
3 Main IPs that should be built and maintained clean, active and validated. 


28 warm up IPs that are used to send emails, identify bounces and remove unengaging contacts. The idea behind the process is to identify the best contacts in your lists, those who engage and trust your emails. Then move the good addresses to the Main IPs and continue communicating with the engaging contacts using the IPs that you aim to keep healthy. Indeed, the warm up IPs will be eventually burned and out of use. However by then, you should be able to reach a point where you own clean, verified and segmented lists of people who know who you are, trust your emails and engage with your messages. 
Deep segmentation of the contacts lists to allow personalized and worth-adding communication that leads to higher engagement (that leads to bettering the sender reputation).

What do you mean by email deliverability service, and what are the advantages of B2B email deliverability services?

An email marketing agency that claims to provide email deliverability service, should be able to plan & execute cold email campaigns that are delivered to your subscribers’ inboxes. As you can read in this article, email deliverability is a very wide subject that consists of many different factors, all of which should be addressed professionally. It can literally take years to comprehend a good understanding of effective cold email strategies. Working with an experienced cold email marketing agency is probably an option you should seriously consider.

What does it mean when your email has low deliverability?

When your emails have low deliverability it means that your campaigns are not getting to your subscribers’ inboxes.

What are the benefits of Email Deliverability services?

Professional email deliverability services can help you plan your cold email strategy and get your emails to the inbox. Email deliverability service providers will take many factors into consideration. Among them the sending servers, the sending IPs, sending domains, the quality of your lists, sending pace, the content you use, segmentation, healthiness of your lists, design issues, costs and ROI.

Does linking my website in a cold email look like spam?

If your website is flagged or is somehow associated with spam email, you should refrain from linking your website in cold emails. Instead create a new site URL and link to the new address. 
This is true also the other way around: if you send mass emails to unverified lists, or if you engage in spam emailing and link from cold emails to your site, your site can be flagged as spammy.

Given the effectiveness of spam filters, is cold emailing 'over'?

Cold emailing is not ‘over’, spam emailing is. And this is a good thing. Your job is to make sure that your cold emails are not accidentally identified as spam. Yes, it is getting more challenging, but it is not impossible. Following professional guidelines and crafting your cold campaigns meticulously, can get you to fantastic results.

Is cold email spam?

If you comply with anti-spam rules and you follow professional email marketing guidelines, cold email is not spam. 

What is the best service to use when sending cold bulk emails, and what is the best platform to send cold emails from?

To view the best platforms to send cold emails, view our article: The Best Bulk Emailing Marketing Tools.

How can I detect spam traps among my user list?

Make sure to clean and verify your lists regularly to avoid spam traps among your users. You do not want to send emails to spam traps as this will hurt your sender reputation.

What is the best tool for cold email marketing?

The best tool for cold email marketing will be a set of servers, sending IP addresses and sending domains, rotating and delivering to your subscribers’ inbox folders. When choosing the best cold email marketing tools, you should consider deliverability, shared IP Vs dedicated IP, size of allowed database, compatibility with other applications, user interface and of course costs.

How can email deliverability be improved, and How to deal with email deliverability issues?

Email deliverability can be improved by following these guidelines:
1. Use a system of rotating servers and sending IPs
2. Send cold campaigns with rotating sending domains
3. Make sure you clean and verify  your email lists
4. Segment your audience 
5. Only purchase high quality lists
6. Curate relevant, and value-adding content.
7. Use personalized messages
8. Avoid spammy words
9. Create more engaging and compelling content

What is a dedicated IP in email marketing?

In contrast to a Shared IP (the IP that is used to send your emails when you sign up to an email marketing platform), a dedicated IP will only be used by you and no one else. This way, your cold emails will not risk the reputation of the shared IP. Note that until you warm up your dedicated IP, your emails will probably not be delivered to your subscribers’ inbox.

Do I need a shared IP or a dedicated IP for my email marketing?

It depends on the type of email marketing you are planning to do. If you simply communicate with your subscribers, for example active buyers of your online shop or people who opted into your newsletter,  you can use a shared IP. If you engage in cold emailing, you may consider getting a dedicated IP and warm it up, or using your own servers.

In email marketing, what is an IP warm-up?

IP (or SMTP) warm-up refers to the process of establishing a good sender reputation that will allow you to send more emails directly to subscribers’ inboxes. 
It is worth noting that you only need to warm up your IP if you use a dedicated IP address to send emails to your subscribers. You do not need a warm-up if you use email marketing services offered by marketing automation platforms like ConvertKit or Sendinblue as these platforms send emails using their shared IP addresses. HOWEVER, while using their IP is the default option, if they will monitor that your campaign’s opening rates are utterly low, or if your bounce rate is high, the email marketing platform will probably ask you to stop using their shared IP, which may also lead to the suspension of your account and loss of your data. Having that in mind, you want to keep your email marketing performances excellent, never mind the type of IP you are using.