Does Domain Warmup Really Work in 2025?

Have you ever faced big issues when trying to send a cold email campaign from a new domain? If so, you might have noticed that your open and click rates are quite low, often resulting in your emails ending up in spam. This is where domain warm-up comes in.

Today, we'll explore whether domain warmup still works in 2025, what the best practice for domain warm-up is and how it affects your email deliverability.

What Is Domain Warmup?

Domain warmup is the process of slowly sending more and more emails to build a good sender reputation with email services like Gmail, Outlook, and Yahoo.

Instead of sending 1,000 cold emails on the first day, you start with 5 to 10 emails a day and slowly increase the number until your domain is shown to be trustworthy.

The process often takes a few weeks or months. The sender gradually and consistently increases the number of daily emails to send during this time.

Why Domain Warm-up Matters in 2025?

Although inbox algorithms keep changing every year, the fundamentals of email deliverability haven’t really changed.
Email providers still look closely at how people engage with your messages; whether they open, reply, or simply ignore them.

At the same time, spam filters have become much tougher, especially with the rise of AI-driven detection. And if you’re sending from a brand-new domain, you’ll automatically be treated with suspicion until you’ve built a track record of healthy engagement.

That’s why, even in 2025, domain warmup remains one of the most dependable ways to land in the inbox particularly if you’re doing cold outreach or running sales campaigns.

Best Practice for Domain Warm-up

1. Start Small and Scale Gradually

When you’re warming up a new domain, resist the urge to send big volumes right away. Start with just 5–10 emails per day and slowly ramp up—adding about 10–20% more every couple of days. This steady growth tells inbox providers that you’re a legitimate sender, not a spammer.

2. Use an Email Warmup Tool

Manually warming up a domain can take weeks and requires constant effort. That’s why many businesses rely on automation. With Zharik’s AutoWarmup, the process is effortless: our system gradually increases your sending volume, while also simulating natural engagement (opens, replies, “mark as safe” actions).

The result? A healthier sender reputation, faster inbox placement, and far less hassle compared to doing it by hand.

3. Authenticate Your Domain

Before starting to send, you want to make sure your domain is properly verified. You should, at the very least, set these records:

• SPF (to verify your sending servers)

• DKIM (a digital signing for your emails)

• DMARC (to protect against spoofing)

• A custom tracking domain (to look professional)

Without these, your emails are farmore likely to go to spam, no matter how wellu warm up.

4. Avoid Spam Triggers

During warm-up, keep your email copies simple and natural. Avoid using aggressive promotional language, too many links, or pushy CTAs. The goal isn’t to sell right away; it’s to look like a trusted sender. Short, conversational emails work best at this stage.

Most Common Mistakes When Warming Up a New Domain

After running several tests, We've noticed a number of common mistakes people tend to miss when warming up new email accounts.

While a reliable warm-up platform can handle most of these automatically, those taking the manual route should watch out for the following pitfalls:

● Sending Too Many Emails Right Away

A mistake I see all the time is people jumping in too fast with their new email account. They’ll kick things off by sending 20–30 emails on day one and then quickly push their volume into the hundreds.

The problem? To email service providers, that kind of sudden activity looks suspicious and signals you might not be a trustworthy sender. Instead of building a good reputation, you’ll likely end up in the spam folder—the exact opposite of what you want.

The smarter approach is to start small. Send just a handful of emails at first, keep it consistent, and then slowly ramp up your sending volume over time. That steady pace is what helps you build trust and land in the inbox.

● Ignoring authentication records

Before you send a single email from a new account, make sure your authentication is in place.

Think of it like this: if you skip this step, your accounts could get flagged—or even blacklisted—before you ever reach your prospects.

There are three key protocols you need, and here’s what each one does:

• SPF (Sender Policy Framework): Tells email providers like Gmail and Yahoo that your messages are being sent from an approved server.

• DKIM (DomainKeys Identified Mail): Adds a digital signature to each email so providers know it hasn’t been altered in transit—this is what proves your email’s integrity.

• DMARC (Domain-based Message Authentication, Reporting, and Conformance): Acts as the final checkpoint. It lets you define what happens when an email fails SPF or DKIM, giving you control over how providers handle suspicious messages.

If you’re planning to use your accounts for cold outreach, don’t skip this step. Set up all three protocols right away. It’s the foundation of deliverability.

● Not Monitoring Bounce Rates

Every time you hit a non-existent or invalid address, it counts as a bounce. And with each bounce, your reputation as a sender takes a hit. Internet service providers (ISPs) treat high bounce rates as a warning sign, which can drag your deliverability down fast.

The fix is simple: monitor your bounce rate from the very beginning. If you see it spike, stop your warm-up immediately and clean up your list before sending again.