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How to warm up IP (email deliverability best practices)

When you build a new SMTP server or opt-in for a brand dedicated IP in email marketing companies; your first email will most likely go to spam. This has more potential of happening to a new SMTP server than a dedicated brand IP address. So, in this guide, I will focus on how to warm up the IP of a newly built SMTP server. This is because emails sent via a newly built SMTP server have a zero possibility of going to the inbox. In this guide, you will get to master and understand not only email deliverability issues. You will understand email deliverability best practices, that will help you to become an email deliverability specialist. So, let’s go ……….

As said before; When you build a new SMTP server and send your first email it goes to spam. This occurs when all technical conditions such as SPF, dkim,dmarc, 10/10 sending score on mail-tester are already in place.

What is warming up

This is the process of sending emails slowly to build a reputation. In your new SMTP server, you need to send emails slowly to gain the trust of internet service providers. This sends a signal to Email clients like Gmail, yahoo, outlook, etc that you are a genuine sender.
How to warm up IP

Why do you need to warm up IP before sending?

You need to learn how to warm up IP for your new server. This is important so that you can get the trust of internet service providers that you are a legitimate sender. There are approximately 3.8 billion emails across different ISPs. If there are no laws against spamming the internet will be filled with spam messages fatigued in people’s inboxes. I’m sure you will be frustrated if you wake up and see your inbox filled up with unsolicited emails. So, the rule here is that you must warm up your SMTP server. This will help to send emails to your subscriber’s inbox. If things are not like that, one spammer somewhere in the world will set up 100 SMTP servers and start sending unsolicited emails to your inbox, ridiculous right? so, don’t spam my guys…..Lol.

How long Does it take to warm up IP

There is no specific length of time or strategy on how to warm up IP or SMTP server, it all depends on your need and the size of your email list. For instance, if you have a 1k email list it will take you less time to warm up your server to send 1k emails at once per day. But if you have a 10k email list, it will take you more time to warm up your server to send 10k emails at once per day. Generally, you can warm up your server between 2-12 weeks. As hinted before; warming up your server requires you to send emails slowly. For you to know the number of emails to send per day, you need to schedule your email for sending. You can determine the number of emails sent per day either by using your head or by using an email warm-up generator. In a nutshell, this is a chart that shows you how to warm up IP for a 1k list.
How to warm up IP
You can visit h-supertools to generate the best schedule for your email list just like the one below:
Postal SMTP Setup Guide
Postal SMTP Setup Guide
The above Schedule is for a 1k email list. You can generate and work with your respective list size.

Tips to warm up IP

Here are a few tips you need to master on how to warm up IP in order to successfully get your server up and running and land your emails in the inbox.

Bounce Rate

This is the measure of the number of emails that bounced back from the receiving server. You get a high bounce rate when you send campaigns to email addresses that do not exist. Here are the reasons why emails might not exist.

Expired Domains

There are a lot of domain emails out there whose domains are expired. Sending messages to the emails associated with these domains it will lead to a high bounce rate on your server. This is due to the fact that those emails do not exist any longer. When you send out emails to a list containing expired domain emails, the email sent will return an error message from the receiving server telling you that the email is non-existent. When you build a new SMTP server and before you send out any email, make sure to validate your list in order to remove non-existent emails. You can validate your email list by using services like or zerobounce. This will help you keep your list clean and reduce the bounce rate which will, in turn, increase your inbox rate.

Spam traps

Spam traps are virtual email addresses created by ISPs and spread over the internet to help them lure spammers. This is to send their emails to the hell of spam folders. In a real sense, spam traps are email addresses not owned by anyone. They are placed in different parts of the web. Most spammers, especially bulk mailers, on their quest to harvest emails online will extract these spam traps. Once you send emails to a spam trap using your new server your IP will automatically be blacklisted. You will now have to start from square zero for that server will be irredeemable. So it is very important to stay away from scrapped lists as much as you can. And in the case where you must scrap emails from different unsolicited sources, make sure to Validate the emails with the above-recommended services.

Recycled Spam Traps

Another form of spam trap is the recycle spam trap. These are emails that have been abandoned by their owners for so long that they are now being converted into spam traps. when you send emails to these non-existent email addresses, it will bounce back from the receiving server and be recorded as a spam trap. By this, you will be identified as a spammer and your server will be blacklisted.

Recipient Interaction:

When we talk about how to warm up IP, the interactions of your recipients are very important for your SMTP or domain reputation. If users or subscribers are reporting your emails are spam you will accumulate a very bad reputation. This sends negative spam signals to the different ISPs that you are a potential spammer. Make sure when you send an email, you keep track of your recipient’s interactions. If your subscribers are reporting your emails as spam, stop your campaign and check the message you are sending to see what was wrong. If it contains a spammy subject or message, change the content of your messages and continue. You can also use some form of personalization but don’t use it too much. Utilize the Fname feature on your mailwizz email marketing application or any application you are using to create some form of familiarity. Through this, the percentage of complaints will be less.

Your sending score

A high sending score is very crucial for your SMTP warmup. Make sure you configure correctly SPF,dkim,rdns,dmarc, and other technical details to be able to authenticate your server well for sending. You can learn about these technical details in my Postal SMTP Setup Guide. To learn in-depth about these technical details enroll here in my SMTP free crash course.

How to warm up IP (No promotional emails)

Make sure to not send promotional emails during the warmup period. Only send simply transactional emails or just deliver valuable info without links. Never send what will shock your subscribers as this will make them report your emails as spam and you will rap up bad reputations. This means emails from your domain and IP may not see the light of the inbox.

Send to the top active users

In the top email marketing companies like getresponse, Sendinblue, activecampaign, you can track your customer’s engagements such as open rate, click-through rate, etc. If you are using an email marketing application like mailwizz you can also keep track of opens and clicks too. After setting up an SMTP server, make sure you export your most active subscribers and use it for the warm-up, by this you won’t get many spam complaints and complaints rates.

No IP Rotation

make sure not to rotate server IP during the warm-up period. If you are using more than one IP, Finish warming up one IP address before moving to another IP. During the warm-up period, ensure to add an unsubscribe link and email signature such: as the company’s address, website, postal code, etc in the warm-up email. This will help to build more trust with the different email clients and they will allow you access pass their spam filters.

Split your campaigns between your new IP and a premium SMTP service

This is very important to shorten your SMTP warmup period. Make sure to split your emails between your SMTP server and premium SMTP services such as amazon ses or mailgun, etc. This will help to give some level of reputation to your new domain as most of the emails sent using amazon ses and mailgun would probably go to the inbox. This helps to give reputation to your domain faster and overall shortens your warm-up process.

Join newsletters.

Another way to skyrocket the trust of your server by email clients is by joining other newsletters. By doing this Email service providers will know that your emails are active and will build your reputation faster. Make a list of emails to send to during warm-up or simply use premium warm-up scripts such as warm-up inbox to do your reporting concept: To do this manually, make a list of emails, send emails to them and reply to them. You can also send your friends emails asking them to reply back. By this, the server will warm up very fast. There are also tools like; warm-up inbox that can help you warm up automatically. They will automatically help you to auto-reply to emails without you replying to them manually.

Build real followership online

If you have real fans following and eagerly waiting for your content, warming up will be a lot easier for you. They will automatically report your emails as ‘not spam’ and help you build a reputation faster. In all you do, make sure to build a real audience that loves your content.

Monitor everything carefully

Make sure to keep track of the above-mentioned tips and monitor everything at each step of the way and if you see anything wrong; stop your campaign, fix things up and continue your warm-up. Conclusively, there are other ways to warm up IP faster aside from the ones I mentioned here. Please comment on your favorite warm-up strategy below so that we can all learn together. Don’t forget to post your questions in the forum or send me an email at [email protected]. Good luck with your campaigns.
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