2 October, 2025 by Libor Nádvorník

Have You Changed Your Tool? New Beginnings Await

Switching Email Service Providers may seem like a small change, one that no one will notice. For your recipients, that really should be the case (just make sure to upload all bounced and unsubscribed addresses into the new platform before sending). But behind the scenes—both technically and reputationally—this change matters a great deal. The old saying applies here: measure twice, cut once – and maybe even measure three times. Precision and care are important, because mistakes can have a long-lasting impact.

Establish Who You Are, And Why You Deserve Trust

If you are starting email marketing from scratch, you're a completely unknown sender to inbox providers (like Gmail, Seznam, Yahoo). They have no experience with you, don’t know what to expect, and have no reason to trust you yet.

In order to start building a reputation that is attached to your sending domain, you must first set up authentication properly (SPF, DKIM, DMARC) to make it clear that you are transparent, secure, and not easily exploited. Without this, you can't even hope to deliver anything.

However, what many senders do not realize is, even if you've sent emails before, but you are now switching platforms, you're effectively starting from ground zero again. The combination of your existing sending domains with a new platform and IP ranges will mean recipient servers are not able to connect the dots between your new and past reputations.

At the end of the day, these are machines, and they don’t care if you are well-known. They judge based on “zeros and ones.”

The First Impression Is Everything

Imagine how the provider sees you:

„Who is this new sender? Are they experienced? Where are these contacts from? How often will they send? Are they a spammer?“

Even if you've sent hundreds of thousands or even millions of emails before, your reputation won’t carry over immediately. The same applies if you paused sending for months at a time (or longer) and resumed, even with the same tool.

You need to go through a reputation “warm-up”, which means:

Starting with a few thousand contacts per day
Gradually increasing volume (e.g., by 20% daily)
Choosing your most engaged contacts first
Monitoring results and consistency

Consistent behavior helps inbox providers feel safe with you, which is exactly what you want.

Build a reputation – and most importantly, maintain it

Earning trust from inbox providers takes anywhere from weeks to months, but that trust can be lost with one bad campaign. Once they trust you and know what to expect from you, you have the right relationship: your messages are delivered, results stabilize, emailing starts to work.

To maintain that trust, you need:

A clear communication plan
A predictable sending rhythm
A clean, high-quality database of emails
Effective segmentation and personalization
Separate campaign types (newsletters, promos, reactivation, etc.)

Inbox providers essentially keep a diary of senders' behavior.

🟢 A Trusted Sender:

“Sends 450,000 emails per month consistently.”
“Growth is gradual and controlled.”
“Recipients respond positively.”
“I trust them.”

🔴 A Suspicious Sender:

“He sends 10,000 one day, 200,000 the next.”
“He knows no order. He sends randomly, unpredictably.”
“Results fluctuate like a roller coaster.”
“Complaints often arise.”
“I don’t like this, so I’ll treat them accordingly.”

It is therefore essential that your communication feels consistent, understandable and predictable. This will make the inbox provider feel secure – and that is exactly what you need.

Timing Matters

Plan your platform change carefully. For example, if you’re already sending campaigns, avoid switching right before the peak season.

It's not just about implementation, onboarding, or domain reconfiguration. You also have to consider the warm-up strategy and the risk of mistakes that can be really painful during the season.

Real-World Example

One of our clients contacted us with an acute deliverability problem with a large inbox provider. This was causing them to lose a significant portion of their business over the long term. At the same time, they were preparing to expand into new markets.

Unfortunately, they only addressed everything right before Black Friday, which is basically before the Christmas season. Their warehouse was full, they expected fast sales, and so they pushed for a massive campaign—but that’s not how deliverability works.

We explained that the ability to deliver emails is not determined by the wishes of business owners, but rather by a system with clearly defined rules which cannot be bent according to individual needs. Together we chose a realistic plan, invested the necessary time, and set everything up exactly as it should be. The result? Long-term cooperation, stable deliverability, and growth in more than 12 markets.

Conclusion

E-mailing involves communication between the sender (you) and the recipient (the inbox provider), who must first receive your message and then "serve" it to the recipient.

Therefore, it is in your best interest to have the best possible relationship with such a recipient, because if you don't deliver what they expect, you won't sell anything.

Providers expect: