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.

When you get a new phone, you don't run heavy apps right away. You have to charge it first. You also can't just start sending hundreds of emails from a new domain/Email Address and expect them to show up in people's inboxes. Email warmup is a technique that slowly build and imrove your sender reputation and helps your emails get to the inbox instead of the spam folder.

What Is Email Warmup?

Email warmup is the process of gradually increasing the number of emails sent from a new or inactive email account so that internet service providers (ISPs) and email platforms (such as Gmail, Outlook, and Yahoo) come to trust your address.

Instead of appearing "suspicious" by sending bulk campaigns all at once, warming up signals that you are a genuine, responsible sender engaging in genuine human-like activity.

But it’s not that simple. A series of factors are involved in assessing your reputation. Firstly, ISPs look at how recipients engage with your emails. Do they open them? Do they click on links, ignore the messages, or delete them? This is exactly where Email Warmup comes into play.

Do Domains Need Warmup Too?

Yes. In fact, it usually takes longer for a domain to warm up compared to a single email address.

Why Email Warmup Is Important

You might think you can simply start sending a low volume of emails directly to your potential leads instead of running warmup campaigns to seed accounts first. But why not? Well, here’s the catch.

Email warmup campaigns are specifically designed to build a sender’s reputation and improve deliverability. In contrast, regular email campaigns are created to drive clicks, conversions, and sales. Even the most well-crafted marketing emails, sent to a highly engaged audience, can still end up with disappointing open and click rates. Why? Because if only a handful of recipients flag your emails as spam, your entire campaign risks being filtered into the spam folder—leading to blacklisting of your domain or email account.

Moreover, there are ever grater reasons why you need to warmup your email account.

1. Builds Trust with Email Providers

Email providers like Gmail or Outlook can be considered as strict gatekeepers. They don’t let just anyone walk in and start sending hazards of messages. If they see a brand-new account suddenly pumping out bulk emails, it looks suspicious; almost like spam. Employing email warmup, you’re essentially showing these gatekeepers that you’re a trusted sender with a natural, steady pattern. Over time, they begin to trust your email address and allow more of your emails through to inboxes instead of blocking them.

2. Improves Deliverability

Even if you write the most engaging email in the world, it won’t matter if it lands in the spam folder. Email warmup prevent that to happen. When your address builds a healthy track record of sending small volumes that get opened and replied to, providers take it as a sign that people want your emails. The history you make enhance your deliverability, which means your future campaigns are more likely to land in the inbox where people will actually see them.

3. Protects Your Domain Reputation

Your domain reputation is like your credit score in the world of email marketing. Once it is ruined by a sudden spike of bulk emails, spam complaints, or too many bounces, it’s incredibly hard to rebuild. A bad reputation can follow your domain for months or even years. Warmup acts as a kind of insurance. By starting slow and building gradually, you keep your reputation safe and avoid mistakes that could leave long-term scars on your domain.

4. Prepares You for Scaling

Warmup isn’t just about the first few weeks of sending—it’s also about the future. Once your address has built trust and reputation, you’re in a much better position to grow. That means if your business wants to move from sending 20 emails a day to 2,000, you’ll be able to scale without raising red flags. Without warmup, those same 2,000 emails might get blocked outright. With warmup, providers are more likely to see the growth as natural and allow your messages through.

How to Warmup Your Email Account

There are two main options to warm up an email account: manually and automated.

How Manual Warmup Works

Doing it manually gives you the most control over the process, but it also requires patience. The idea is simple: start by sending a small number of emails each day to people you know and trust. This could be your personal Gmail, an old Hotmail address you still have, or even accounts you use for other projects. Once you’ve covered your own bases, involve friends, family, or colleagues who don’t mind lending a hand.

The goal here is to send messages across a variety of inbox providers (Gmail, Outlook, Yahoo, etc.) so your address looks trustworthy everywhere. And remember—it’s not just about sending. Engagement matters just as much. Ask your contacts to open the emails, reply when they can, and, if one of your messages slips into the spam folder, move it back into the inbox and mark it as safe.

The upside? Manual warm-up is completely free. The downside? It’s slow, and it usually relies on the goodwill of people in your network.

Automated Warm-Up

Since all of these manual efforts would probably sound like a chore, there are tools dedicated to taking care of it for you. Zharik is an all-in-one warmup tool that connects to your account and provides real human interactions such as opening, clicking, and replying to emails. This platform utilizes a network of real humans, referred to as seeds, who actively open your emails and engage with your email account, ensuring an effective warm-up that maximizes your deliverability.

That said, not all tools are created equal. Before you sign up for one, it’s worth digging into how the service actually works. A few key things to consider:
• Are they using real, active accounts, or just throwaway email addresses?
• Do the emails contain meaningful text, or are they filled with gibberish?
• Is there genuine engagement—opens, replies, and inbox recovery—or just empty sending and receiving?

These details make a big difference. A well-built warm-up service can fast-track your deliverability. A poorly designed one can do more harm than good.

How Email Warm-Up Powers Your Cold Email Strategy

Cold email by nature can feel… well, cold. You’re showing up unannounced in someone’s inbox, and if you’re not careful, you might get treated like junk before you even get the chance to introduce yourself.

That’s exactly where email warm-up fits in. It’s not a fancy add-on—it’s the foundation. Think of it as the small talk before the pitch, the stretch before the sprint, or the rehearsal before opening night. Without it, you’re walking into the room unprepared.

First Impressions Happen Before the Reader Even Sees Your Email

Here’s the thing: your prospect isn’t the first one judging your message—email providers are. Gmail, Outlook, Yahoo… they’re all scanning your activity constantly. If a brand-new email account starts blasting out dozens of messages a day, alarms go off. To them, that screams “spam.”

Warm-up fixes that. By sending gradually, getting opens and replies, and looking more human in your behavior, you build a track record. Over time, providers start to recognize your account as safe and trustworthy. Only then do your messages stand a real chance of landing in the inbox where your prospects can actually read them.

It Lays the Groundwork for Deliverability

Skipping warm-up is like trying to plant seeds in dry soil—it just won’t stick. Even the best-written cold emails can vanish into spam if your sender reputation is shaky. With proper warm-up, you’re essentially preparing the soil so that when you do start sending real campaigns, your emails have the best chance to take root.

Warm-up gives you:

• Higher inbox placement rates (not spam or “promotions”).

• A growing sender reputation that compounds over time.

• Protection against blacklists that can kill your outreach overnight.

• Signals to ISPs that you’re a genuine sender, not a fly-by-night spammer.

It Buys You Valuable Time

Another underrated perk of warm-up is that it gives you a built-in window to get your cold email strategy polished. While your account is slowly ramping up, you can:

• Write and refine email templates that feel personal, not pushy.

• Do deeper research on your target audience.

• Segment prospects into groups for more relevant outreach.

• Test different subject lines and calls-to-action.

By the time your email account is fully warmed, you’re not scrambling—you’re prepared. You’ve got both a sender reputation that providers trust and a message strategy that prospects are more likely to respond to.

Final Thoughts

Email warm-up isn't just a technical trick; it's an opportunity to build trust.  You wouldn't yell your name when you first met someone; instead, you'd start small, show that you're real, and let trust blossom over time.  That's exactly what email warm up accomplishes.

By taking the time to warm up properly—whether manually or with the help of a tool—you protect your domain, improve your chances of landing in the inbox, and set yourself up for long-term success. More importantly, you make sure that the effort you put into writing your campaigns actually pays off, because your emails are being seen.

So if you’re serious about cold outreach or scaling your marketing, don’t skip this step. Warm-up may feel like a slow start, but it’s what makes sure your emails reach the right people when it really counts. In the world of email, patience and preparation aren’t optional—they’re the secret to lasting results.

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