• by Ray Schultz , Columnist, Yesterday

The much-hyped tactic of warming up your domains to ensure your emails get into the inbox may not be sure-fire. 

It was only a few weeks ago that Warmy.io, an email deliverability startup, urged marketers to try the warmup – that is, to start with a small number of emails, not a high volume. 

But it’s not enough, the company reports.  

Google and Yahoo have transitioned from “soft enforcement to Active Replacement, making a sudden, unexplained drop in email open rates “the new normal.”

The result is that emails with low-sender reputation aren't simply being sent to the spam folder; they never reach the recipient at all. 

"The era of dry technique is over," says Daniel Shnaider, co-founder and CEO of Warmy.io. "The algorithms of 2025 are not just looking for proper server settings, but for proof that there is a human being on the other side interested in the content.”

Shnaider adds: "Without the engagement layer – clicks, opens, and replies, your email is 'transparent' to Google. This shift is no longer a recommendation; it is a necessity of the new business reality."

Warmy.io compared two methodologies: "Standard Warm-up" (volume-based) and "Warm-up with Clicks" (a hybrid approach utilizing opens, replies and other interactions).

The result? The study found that the Standard approach delivered a 4.56% improvement for a 79.26% deliverability rate. 

In contrast, the engagement method delivered a 37.30% curve for an 87.30% inbox placement rate. 

We suggest you test this for yourself before taking it at face value.