Maildoso Deliverability Guide

Your sequence is your main deliverability enemy

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.

In this guide, you will learn how to make your email land in inbox.

Keep in mind, that these tips are valuable regardless of what cold email infrastructure you use to send cold email: Google Workspace, Microsoft Outlook, or Maildoso.


If you are a maildoso customer and your open rates are lower than 50%, reach out to customer support.

We will help you to get back into inboxes.

Send text-only emails

Spam filters try to protect their users against 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.

How to enable text-only mode on Smartlead

How to enable text-only mode on Instantly

How to enable text-only mode on Saleshandy

Still a fan of tracking open rates?

If you are a Smartlead user, stick to text-only campaigns.

They send text-only warmup emails.

Open rate tracking is only possible in HTML emails.

Email providers will quickly ban all HTML emails from you.

Since only HTML emails receive spam complaints.

Text-only emails get a ton of positive feedback.

Hence, no HTML emails.

If you use instantly, don't forget to enable it

For instantly users, there is a killer feature that you need to enable if you wish to track open rates.

First, you need to enable custom domain tracking.

In Instantly it takes a ton of time. However, you can do bulk operations there.

Also, you can use one custom domain for all your mailboxes to save time.

Now, it is time to enable warmup of the custom tracking domain.

This feature is hidden in the " advanced " mailbox warmup settings section.

Do you want to level up your deliverability?

Avoid using images and links in your first email

Unsubscribe link is okay, as long as you have custom domain tracking enabled.

In other cases, it's better to replace it with unsubscribe text:

🚨 Signature

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 emails from you that contain this specific phone number.

Try to keep your signature as simple as possible. 

Avoid adding:


If you are a maildoso customer and your open rates are lower than 50%, reach out to customer support.

We will help you to get back into inboxes.

Check for spam words

Make sure to have zero spam words according to this 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.

Always have multiple campaigns running at the same time

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 get 10% and another 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.

Add as much SPINTAX as possible


The more spintax you have the better

Not enough of spintax

This is a healthy level of SPINTAX

Change campaign every couple of weeks

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.

Do you want to level up your deliverability?

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