ZeroBounce’s Sterg Dikos on The Smarter Way to Do Email Marketing 

Quick Answer

What’s the most important thing you can do to improve your email marketing?

Short answer: Keep your data clean by validating your email list regularly.
Why it matters: Without good data, nothing else works. Clean, accurate email addresses protect your sender reputation, improve inbox placement, and make sure your message actually reaches real people who can buy, click, or engage. Clean data is the foundation on which every other email strategy depends on. 

Sterg Dikos understands how companies get better results with email. As the Manager of Account Growth & Retention at ZeroBounce, he spends his days working with businesses that clean their data for stronger deliverability. 

Having a game plan for handling email validation is the ticket to more reliable performance from every send. Sterg understands where marketers struggle, and he’s seen firsthand how much can change when you treat email as a long-term system — not as “one-and-done.”

In this interview, Sterg Dikos shares practical advice on how to build a healthier approach to email. He explains why clean data is the foundation of successful email, how often different types of lists should be validated, and why a structured, step-by-step approach helps teams avoid overwhelm. 

Follow his tips and you’ll give your emails a far better chance of reaching real people who can engage, click, and convert.

You’ll learn:

• Why every successful email strategy must start with clean data
• How often to validate your email lists
• How to reduce stress by breaking your email workflow into small steps in order to stay consistent
• How email validation protects revenue by helping you reach the inbox
• Why email success comes from good habits, and not one-time fixes

You can also watch our interview below!

You hear that ticking sound? I hear a tick. Oh! That’s you, Sterg, because you’re one of the people who keeps ZeroBounce ticking.

I’m excited to be here and chat with you. I’m excited to get into it.

Why regular email list cleaning matters

Sterg, if you could wave a magic wand and make people who use email understand one thing, what would that be?

This is probably expected coming from someone who works at ZeroBounce, but it’s email validation. The way I explain it is that it’s the foundation of all email sending, no matter what vertical you’re in. If it’s cold outreach, it might be even more important. But with any type of email sending, you want to make sure you’re sending to good, real people.

There’s a lot that can go wrong if you don’t. If you have an email-sending problem, the first thing to do is always make sure the data is good, healthy, and real. Because if you’re not doing that, it gets tougher and tougher to diagnose what the actual issue is.

If I could wave a magic wand, I’d make sure every email any marketer sends goes to good, real data — actual inboxes. That alone would help a ton.

Email people just love analogies. If you could compare email validation to something else, what is it like?

I’d say it’s like dating. When you’re sending that first email to someone, you want to make a good first impression. If you end up in the spam folder, it’s kind of like getting ghosted when you’re first meeting someone. 

We help make sure you end up in the inbox, that you have the opportunity to make a good first impression and not embarrass yourself on the first date.

That’s very clever! What are the scenarios you see most with the customers you speak with?

We basically handle two types of clients. 

People who are proactive about email sending and validation, and people who are reactive.

The proactive people already know about email validation. They understand that they need to do it before sending emails because they want to make sure they’re only sending to good addresses. They know it’s something you have to do to avoid problems down the line.

Then, there are the reactive people. They usually come to us because they’ve started landing in spam and are trying to figure out why. They didn’t realize how important validation is, and now it’s our job to help them get out of spam.

Those are really the two main types of people we work with. Of course, we deal with all kinds of industries and verticals, but that list gets much longer.

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You don’t shame the people when they’re not the proactive type?

No, absolutely not. (Laughs) They’re in a tough position. For a lot of companies, their revenue comes through email, so it’s a really difficult situation. We probably help them even more than the proactive ones — because there’s more to do.

What scenario do you see where somebody is really checking off the boxes? Email validation is your first line of defense, like brushing your teeth or changing the oil in your car. What are the most successful people doing?

That’s where industry and email type come into play. 

But number one is the frequency of validation. These people aren’t just validating their list once, they’re doing it multiple times a year. Emails can go stale, especially in the B2B space, so the recommendation is every three to four months.

The people doing great are validating often, and they’re also monitoring other things: whether they’re on a blacklist, their inbox placement, and if they’re ending up in spam. They’ve got alerts set up so that if something goes wrong, they know what it is and can fix it fast.

Email warmup also comes into play. If you have a new domain, you can’t just send a hundred thousand emails right away — you need to take steps to build up to that volume. That’s where email warmup helps, getting your sending reputation ready before scaling.

So after brushing your teeth, it’s all about frequency. The people who do really well are checking and maintaining things much more often.

Email warm-up’s rising importance

Right, like so many things in maintenance, you don’t just change the oil in your car one time and say, yeah, I’ve done it. You mentioned email warm-up. I’m a little biased because I’ve used it personally, and the difference was night and day. 

Email warmup is on more and more people’s lips. A lot of conversations,  like the one we’re having now, naturally move from validation into warmup. 

When that comes up, the first thing we do is have them run an inbox placement test. You send to our seed list, and we show you where your emails are landing: whether it’s the inbox or spam. You get a clear snapshot of where you’re at.

From there, it flows into warm-up. You connect your account, and we use a network of seed email accounts across the major ISPs — Google and the others. We send and receive emails on your behalf through that domain. Those emails are opened, engaged with, and some are sent back, which starts to build or repair your sender reputation.

It’s especially useful if you have a new domain, but it’s also valuable for ongoing maintenance. 

And for those reactive clients I mentioned earlier, it’s a great way to repair a domain. If your domain’s running into deliverability problems and you don’t want to buy a new one, because your domain is your lifeline and part of your brand. You can use warm-up to rebuild that reputation and get things back on track.

Understanding the DMARC Monitor tools

People are less familiar with the DMARC Monitor tool. 

It’s basically a monitor for the security aspect of email. We’re making sure that everything on the backend is set up properly and that there are no issues sending emails from your domain. 

As we talked about the different steps: validation, warm-up, and monitoring, the DMARC Monitor helps ensure everything is set up correctly.

It works alongside the Blacklist Monitor. These monitors provide data points so that if something goes wrong, you can check it right away and know you’re covered.

One blacklist status check is free, every month

What happens if you end up on a blacklist?

You mentioned the Blacklist Monitor, and to appear on any blacklist is not a good thing.  What happens when you’re blacklisted? 

It negatively affects your sender reputation. There are a bunch of bad things that can happen, most of all not being able to reach your subscribers. 

You can end up on a blacklist by sending to spam traps or not taking care of the data you’re sending to. If that happens, your emails won’t reach inboxes as often.

It’s a scary word, and you don’t want to be on a blacklist. That’s for sure!

If somebody is practicing routine email validation, do they still have to worry about using something like a Blacklist Monitor tool?

Yeah. At that point, you’re being very proactive about it. 

Why not just have the Blacklist Monitor set up so that if something goes wrong, you can fix that part of the system? Especially with automated validation, sometimes things just break.

You want to know when that happens. Using these tools means taking care of everything you’ve built and knowing that if something goes wrong, you’ll be alerted. It’s a peace-of-mind thing as well.

How inbox placement tests can help marketers

On the note of being proactive, what can an inbox placement test do for an email marketer?

It gives you a snapshot of where you are. 

If it’s your first inbox placement test, you can track your progress with deliverability and sender reputation. It will show, for example, if you ended up in Gmail’s spam folder – that’s an issue. For other ISPs, you might be good to go. Now you know the problem, and if it’s a Gmail issue, you can take actionable steps to fix it.

That’s also where warmup comes into play. You can manage the warmup yourself, targeting specific providers like Gmail, or automate it and let the system handle detection.

It’s a good way to track progress and, in my view, it’s an overlooked tool. It’s the foundation: you’ve done validation, now check your inbox placement.

Related: See what Gmail creator Paul Buchheit says about the simple reason people get marked as spam

So do you think that the inbox placement test is the most overlooked or the most underrated of our tools?

I would say the inbox placement tool is the most underrated tool. You can use it to track progress. For example, if your first inbox placement test shows 30% of emails going to spam, you can warm up and repair the domain. Then, a month later, you run another test or do them continuously. And you may see that now only 10% are going to spam.

It really helps identify the next step in improving your deliverability.

Try the inbox placement tester for free

Why you need an email server tester tool

What about the email server tester tool? What does that do?

The email server test checks that everything is functioning properly on the server side. It’s another useful tool on top of everything else. After validation and an inbox placement test, and deciding if warmup is needed, the email server tester works alongside the DMARC monitor and blacklist monitor to ensure everything is running smoothly.

What you need in an email finding tool

There are many, many email finder tools out there. Some of them hook onto your LinkedIn. I reach out to people, and obviously use the tool, and it is different. What is different about the ZeroBounce email finder?

It’s in the name – it’s connected to ZeroBounce. That means the data coming out of it is good, and we have high confidence that the email is valid and safe to send to. It combines the functionality of typical email finders with the assurance that the data is accurate, which streamlines the process for users.

So, typically if you’re scraping emails offline, you end up with a list that then needs to be validated. With our email finder, it combines both steps into one seamless process.

Right. I used pretty much all of the email finding services out there, including the big-name ones. I’d uncover an email address that would be at msn.com, which was a popular domain back in the 90s. Or this person had switched a whole bunch of jobs and it would return like ten email addresses, all invalid.

Yeah. What’s neat about our email finder is that if you have the first and last name and the company domain—not just the company name, but the domain, which is a unique identifier, it makes a big difference with your results. 

Multiple companies can have similar names, but the domain helps pinpoint the exact email. It’s a no-brainer because it makes identifying the right email much more accurate.

Looking for that email address? Try Email Finder

Automating validation so it runs in the background

So for somebody who’s hearing us talk about all of these different tools and they’re thinking: “Okay, now this is just overwhelming.” 

I would say let’s start as we would with anything that seems like a big task: let’s break it up into steps. 

Let’s take a look at your data first. Where are you collecting it? What does it look like?

If it’s in the B2B space, I’d recommend validating that email every three months. 

In the B2C space with more personal emails, they don’t turn over as often, so you can get away with validating those every six months.

So I would say, let’s just set up a process where that is taken care of. We have a bunch of really great integrations, especially with HubSpot. You can automatically set that up through different segments and lists. 

Let’s hop on a call, go through it, and get you set up so that is step one – just automating that process.

Then we go to step two. 

Breaking it up makes it simple, focusing on one thing at a time. 

In this space, there’s a lot of terminology and technical details that can feel daunting. So just take it step by step. With any big goal, big achievements don’t happen overnight, but focusing on small, easy wins makes it manageable.

What do you get when you use email deliverability tools?

So if you tie all these tools together, what does somebody get? What do they get if they do all this work?

It’s simple. They get their messaging in front of more people. And if they’re looking to make money through email, it’s a vital thing to do. You almost have to do it. There’s no way around it. 

You can maybe get away with it for a couple months, but it’s going to catch up to you. So if email is a channel of revenue for your business, or anything that you’re doing, it might just not even be revenue, but just exposure that can eventually lead to revenue. 

That’s what you’re getting. You’re getting another marketing channel that is useful and that can make money for you.

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If ZeroBounce was a movie, what would it be?

So if you were to compare your time at ZeroBounce to a genre of movie, what would the movie type be?

I’m gonna go with a thriller. It’s definitely a thriller!

In every good way that a thriller movie can be: high pace and a lot of action. It’s been a great time, honestly, and very exciting, especially at the point that we’re at and watching ZeroBounce grow is thrilling.

It’s an adrenaline booster. Wow, that’s great, that’s great. Now, I always like to ask this question: what can anybody do today to make today better?

To make today better? The one thing that always makes the day better, I always say, is go outside, maybe walk, get some sort of blood flow going through your body. Go work out, go take a walk – whatever working out means to you. I never felt worse after I went and moved my body around.

If you’re in a rut today, if things are tough, go move your body, get your mind off things. Focus on that, and it will be a better day afterwards.

Sterg, you are wise. The brain is the body and the body is the brain.

Yeah, and they work hand in hand. So that’s what I do. It’s worked for me.

Sterg, thank you so much. I’ve enjoyed this a great deal.

Absolutely. Well, thank you, Paul. It’s been fun!

Want your emails to reach people instead of spam folders?

Sterg Dikos wants everyone to remember that clean data isn’t optional. Why? Because it’s the backbone of every successful email marketing program. 

With your email list full of healthy contacts, you’ll find that everything else works better. Remember that email deliverability makes engagement possible, and that’s what leads to revenue. 

With ZeroBounce ONE you’ll have all the tools you need to validate, monitor, and keep your email performance secure all year-round. You won’t have to worry about bounces, and that way you can focus on results. Ready to give your emails an unparalleled advantage? It starts with one.