Cold Email Deliverability Guide: Get Your Emails to the Primary Inbox

Email providers pay special attention to the content of your email. They are looking for red flags. If your emails are suspicious, they won't land in the inbox.

This guide will teach you how to make your email land in the inbox. Keep in mind that these tips are valuable regardless of the cold email infrastructure you use: Google Workspace, Microsoft Outlook, or Maildoso.

Spam filters aim to protect users from phishing attempts and malware. Text-only emails are the safest from that standpoint.
So more people will receive your email because it looks safe.
You won’t be able to track open rates, though. But your replies will increase.
At least create a text-only copy of your campaign and test it.
Top 10% of maildoso customers use text-only mode for cold outreach.

Still a fan of tracking open rates? Forget about it. If your email contains an open tracker, Google will display this warning to its users.

The unsubscribe link is okay as long as custom domain tracking is enabled.
In other cases, it's better to replace it with unsubscribe text:

• “I will follow up with you in a few days. Let me know if you don’t want to.”
• “Reply 'not interested' if you want to opt-out of future emails”.
• “Reply "not interested" if this is not relevant”.
• “If you don't want to hear from me anymore, just let me know.”

You won't believe it, but this element of cold email causes the most deliverability issues. Because even if you use a lot of spintax, some elements of your signature will be the same across all your emails (for example, a phone number).

This is how it works. An email provider receives spam complaints from 10 different people. It spins up its machine learning algorithms to find what's common between all 10 emails. Quite often it's a phone number.

So they start banning all your emails that contain this specific phone number. Try to keep your signature as simple as possible. 

Avoid adding:

• links/domains;
• phone numbers;
• license numbers;
• photo.

Make sure to have zero spam words according to this spam checker tool.
Don’t forget to check your signature and unsubscribe text too!

Even just one word can hold you back from getting a solid 70% open rate.

At some point, email services will start banning some parts of your copy.

The greater variability you have, the better deliverability you can achieve. You will notice that after some time, one campaign will have a 10% open rate and another an 80% open rate. This indicates that the email provider blocked some words or sentences in the first campaign.

A good moment to put it on pause and create a new one.

Spintax (“spinning syntax”) is a way to randomize specific words and phrases in your emails. The most basic example is your email greeting:

{{ hey | hi | Hello }} Marc

Whenever you send an automated cold email, spintax will choose a variation, so one batch of emails will go out with “Hey, Marc,” and others will be sent with “Hello, Marc.” (Source).

This is not a sit-and-forget type of game.

Your job is to outrun the algorithms of email providers if you want to have great deliverability.
This is certainly a game not for lazy people.

If you want to get tons of replies, update your campaigns regularly.

A higher warm-up-to-cold-email ratio helps offset spam reports from cold emailing.

For example, if you send 10 warm-up and 10 cold emails, and 5 of them mark you as spam. This becomes 5 out of 20, which is 25% of sending.

But if you do 60 warmups and 10 cold emails, then it becomes 5 out of 70, which is 7% of your sending.

This way, you minimize spam reports and offset them.

However, this advice is only for maildoso mailboxes strictly. As these are all on our servers, we own everything to decide the limits and behaviours.