If your emails go to spam you do not have to worry. That’s OK. It’s a common phenomenon for emails to land in a spam folder more so when it comes to a new sender with a new SMTP server, Domain, or new IP. Even after ensuring most of the technical aspects are in place such as DKIM, SPF, RDNS, DMARC, there are no Blacklists, and the 10/10 Score on, it’s possible that your emails could still land in spam. As such, on building a new SMTP server whose IP address is new or you subscribe to an SMTP services such as Amazon SES with a Dedicated IP, and before you start sending any email marketing campaign, you should warm up your IP address. Again, you have to warm it up if you had left your IP without sending an email for 30 days or. Thus, you should make SMTP warm-up a continuous process. SMTP is the short form for Simple Mail Transfer Protocol. This is an application used in sending, receiving, and replaying emails between the sender and receiver. The general address for the SMTP server can only be set by the client or the application in use. For instance, if the address for your server is Gmail, then the SMTP address format is Hence, the address for the SMTP server is found in the account settings. On sending an email, the SMTP server would send it while the email provider downloads it and places that email in the inbox of the recipient.

How to do SMTP warm-up

When you build a brand new IP address for your SMTP, it does not have a reputation on the internet, and internet service providers (ISPs) do not know such an IP. IP warmup refers to the practice of establishing your reputation on the internet through a gradual increase in the volume of mails sent using your IP address as per a predetermined schedule and also ensuring there is engagement to your SMTP. This can be done automatically through a tool like Rubedo. On noticing an email coming from a new IP address suddenly, an ISP will immediately begin to evaluate traffic from the IP. And because ISPs treat the volume of email as an important factor when determining spam, it would be better if you started by sending low email volumes and then increase gradually to a significant amount.

It allows email providers a chance to analyze and observe your sending volumes and habits and to record the engagement with the emails by your recipients.  Warming up is an exercise that should take you between 2 and 10 weeks depending on your scenario and the number of emails you wish to send daily. When you have started the process of warming up, ISPs evaluates your reputation in line with the following factors:

Now you have a bigger picture about SMTP warm-up, the following are some examples and real scenarios that will help you further understand how this operation works.  

  1. 1000 emails per day: It’s not such a big deal. You can start sending 20 emails on the first day, then increase them gradually to attain your target of 1000 in 7-10 days. The schedule can appear like this.

Some may say this makes the schedule of warming up longer. This could be true but through such a schedule, you can easily manage and monitor your warming up campaigns and realize better results.

Therefore, if your target is a warmup to 10K, emails should be less. This way, it’s possible to monitor and see the bounce rate and user interaction on a smaller amount of emails because the picture becomes clearer.

Advantages a prewarmed SMTP

A prewarmed SMTP has many advantages. When your campaign is cold, the most important thing is the delivery of your emails. Reports indicate more than 20% of emails do not reach their intended inbox. As such, when you begin a campaign with a cold IP, their emails will be blocked. Inboxing is hard for new emails if they are not prewarmed because most emails send mark as spam. Hence, upon starting a new campaign, you should avoid a serious cold email outreach. Ensure to use warmup services for your emails.

IP or email warm-up increases your IP reputation and particularly for a new one or that which has not been used for a long period. As such, the goal of email warmup is to ensure your reputation is increased and gain trust from email services. It further increases the possibility of your emails reaching your subscriber’s inbox.

Email service providers often count bulk emails emanating from new IPs as spam, hence your emails will end up in the spam folder. An IP warming service protects your emails from going to spam. Pre-warming service continue warming your IPs to ensure your emails do not stay in the spam folder.

A prewarmed email uses a complete and verifiable warming method in sending and delivering excellent emails in the inbox and ensures SMTP and IPs reputations are good. Again, you do not have to worry that your emails will go to spam when the email is prewarmed.


IP warmup is about gradually sending emails to establish a good reputation and ensure you reach the recipient’s inbox. Thus, you need to be careful and follow those tips and guidelines listed above in order to get the best results.

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