Deliverability Interviews – Damien Brenelière from Mailreach

Warmup deliverability Mailreach

Interview 3: This is our third interview in the deliverability series. In this interview we spoke to Damien from Mailreach.

Damien Brenelière is the Co-Founder and CEO of MailReach, an email deliverability SaaS that combines email warming and spam checking. He’s an experienced Growth Hacker that specialized in cold emailing to generate growth and scale the lead generation of 130 companies in 40 different industries.

He used cold emailing to scale his previous company Nimley from 0 to 120k Monthly Recurring Revenue in 6 months and helped raise 56M in funding for IPOs and seed rounds. During his journey, he faced big deliverability issues with all the pain that goes with them in terms of business. MailReach is born to help companies perform better with a reliable and efficient deliverability solution.


In case you missed we published deliverability interviews with Przemysław from Omnisend and Arun from Zoho earlier.


Interview Date: 08 December, 2021

Postbox Services: Damien, Could you tell us how you came up with the idea of Mailreach.co and how this journey started?

Damien: With my Co-Founder, Florian, with whom I worked at Nimley, a B2B growth / cold email agency, we managed the lead generation of 130 companies in 40 different industries.

Nimley had a very strong growth as we went from 0 to 120k Monthly Recurring Revenue in 6 months with cold emails and a team of 5 sales. To fuel our growth and the one of our customers, as you can imagine, we needed to send a large quantity of cold emails every day.

Everything was going well until we had to deal with huge deliverability problems : we were landing in spam for our own lead generation and worst, for our customers too. The nightmare.

It lasted two months and made us lose a lot of customers and money as we’ve had to put all our engineers to work on understanding what we were doing wrong and how to fix our spam issues.

This period taught us two things :

  • Deliverability is a science, it’s a job. You can have the best team of email marketers, copywriters, etc, if nobody knows deliverability or use a deliverability solution, you’re doomed.
  • That’s very hard if not impossible to have a stable deliverability in the long run without a very high level of engagement on your sending address, domain / IP.

This experience gave us the motivation to develop a really efficient and easy-to-use deliverability solution.

Postbox Services: For our audience who are new to the concept of email warmup how would you define the email warmup?

Damien: Today, the level of engagement of an inbox is a very important factor in terms of deliverability. If you send emails that don’t get opened, replied, marked as important and worst, people put them in spam : your deliverability will decrease and you will land in spam very quickly.

Email warm up is a method designed to raise and maintain the sending reputation and deliverability of an email address, associated domain and IP.

It has two main goals :

  • prepare a new domain for sending by gradually increasing the amount of emails sent and generating positive interactions such as openings, replies, marking your emails as important and remove them from spam and categories when needed.
  • maintain and fix the sending reputation and deliverability of any domain by constantly generating positive interactions and balance the email activity during email campaigns.

When the warming activity is done right, it’s a very powerful help for your email efforts.

Postbox Services: You have mentioned “Meaningful Warming Content” and “Smart Warming Algorithm” as two features of Mailreach. What are these and how do they help with warmup and deliverability?

Damien: Most email warm up solutions have a too basic behavior. They basically send random emails from your inbox and get replies, openings, etc.

The problem with sending emails with gibberish content is that the big email providers (such as Google and Microsoft) can understand the content and conversations. This is how their “smart replies” or “quick answers” work, by understanding the emails.

By sending gibberish emails, it does not help build trust with Google or Microsoft.

With MailReach we want to maximize the efficiency of the warm up by using meaningful content and conversations that reproduces a human cold email activity, with positive replies and that can be understood by Google and Microsoft. And that’s the case since they suggest smart / quick replies on our emails.

We also have developed a smart warming algorithm, always with the aim of maximizing the efficiency of the warm up.

I can’t disclose all the secret sauce but to give an example : when your deliverability / reputation decreases or you’re having a spam spike, MailReach will make you talk to inboxes with the highest reputation to fix, maintain and raise your deliverability ASAP. This is one example of our algorithm.

Postbox Services: We have clients who send different kinds of emails for example cold emails, newsletters, promotions, affiliate marketing offers. Is there any difference in the way clients should go about warming up when they run different kinds of campaigns?

Damien: Exactly yes.

For cold emailing, we recommend to follow the “Multi Sender Tactic” : this means sending from different domains, maximum 200 cold emails daily per domain, only one sending address per domain. (we explain everything in this article : “The best sending and warming strategy to stop landing in spam”  https://www.mailreach.co/blog/best-cold-email-sending-strategy/  )

For other uses based on opt in, it’s a bit different. You don’t necessarily need to send from different domains (even though sometimes it’s recommended if you’re in a tricky industry that can easily make you land in spam like health).

But you need to have a warming activity that is proportional to the amount of emails you send. And we recommend between 10% and 25%. This means that if you send 10k emails per day, you’d need to send between 1k and 2,5K of warming emails daily.

To do that with MailReach for example, you’d need to connect several addresses of the same domain to MailReach. MailReach allows to send up to 120 warming emails daily per inbox.

Postbox Services: Does Mailreach help with deliverability improvement with different ISPs like Google, Microsoft, Yahoo/AOL etc?

Damien: We mostly help with Google and Microsoft as they’re the biggest providers but we also help a bit with Yahoo / AOL.

Postbox Services: There are many email warmup services launched in the last year or so. What are some of the unique features mailreach provides?

Damien: Our main differences are :

  • Meaningful content that reproduces a human activity of sending cold emails that get replied positively which sends very positive signals to email providers to teach them to send your emails to the inbox.
  • A smart warming algorithm that constantly adapts to maximize the efficiency of the warm up.
  • A Real spam checker tool that helps you test your emails and know precisely where you land for each major provider with insights to improve your content and sending setup.
  • A very strong experience of sending emails and generating growth out of it for 130 companies in various industries.

Postbox Services: Damien, you have an email marketing and lead generation background before you started Mailreach. What are some of your tips to new businesses for lead generation?

Damien: I would say the following :

  • Learn Copywriting and Email oriented Copywriting
  • Start sending small campaigns and run A/B tests to learn.
  • Read our guide “How to prevent emails from going to spam” to learn the best ways to drive impact and maximize your email results : https://www.mailreach.co/blog/how-to-prevent-emails-from-going-to-spam/
  • Be patient, you need to run several campaigns before being good at it, that’s normal 🙂

Postbox Services: Thank you Damien. These are very valuable insights related to warmup and related best practices.


If you need any help/consultancy with email deliverability or domain warmup please reach out to us