Email warmup is the process of gradually increasing your sending volume to build trust with ESPs and avoid landing in the spam folder.
To run effective outreach, it’s essential to warm up email accounts before sending messages. You can do a warm-up manually, in small, consistent batches, or use automation tools like Snov.io, which replicate human-like engagement to speed up the process.
You’ve heard those horror stories: a company spends hours on crafting a perfect message, only for it to land in the spam folder — or worse, get blacklisted.
To avoid this frustrating scenario and run effective email outreach with high inbox placement, it’s vital to warm up accounts beforehand.
In this guide, you’ll get expert cold emailing tips and learn how to improve email deliverability through warm-up.
Key points of the article:
Email warm-up is the practice of building a strong sender reputation by progressively increasing email volume over time. Sending mass campaigns from a brand-new account can trigger spam filters – or worse, get you banned. By using a good warm-up strategy, you address your ESP’s concerns and improve deliverability in the long run.
Email outreach is a lot like the start of a romantic relationship – it needs some warming up if you want the other person to commit.
Translated into email marketing, to win over your prospects’ love, your messages need to reach their inboxes first. To make it happen, you should ensure your email service provider (ESP) can trust you.
About 60% of senders call spam folder issues their number one email outreach challenge. Meanwhile, about 5% of businesses struggle to build a solid sender reputation.
An effective warm-up is one of the email marketing best practices that helps you address these issues, bringing you:
By warming up your email account, you literally teach your ESP to trust you. You’re increasing your workload naturally, so the provider doesn’t notice any red flags. This helps you avoid any risks of being blocked or blacklisted.
As you become credible in the eyes of your ESP, you are less likely to be sent to spam folders. Instead, you start reaching others’ inboxes more frequently, which helps improve email deliverability.
As recipients start receiving and responding to your messages more often, this signals to ESPs that you’re a sender people love to engage with. This naturally boosts your sender reputation.
A gradual warm-up and the high sender reputation you’ve already built let you increase the email volume. Becoming a mass sender with a high inbox placement rate, you have all chances of growing conversions and meeting your sales goals.
Preparing an account for email outreach requires some time and effort. And that’s where you need to choose between two warm-up methods: manual or automatic.
In 2025, I highly recommend using an automatic email warm-up tool. It saves you enormous amounts of hours, not distracting you from other important tasks. With just a quick sign-up, you can set it up and let it work its magic.
Let me just show you how to improve email deliverability through warm-up with one of the best email warm-up tools on the market — Snov.io. For your convenience, I’ve broken down the process into several clear steps.
Before you launch your first campaign, it would be best to create a brand new mailbox. When done, sign up for Snov.io and go to the Email Warm-up page. Pick the account to warm up and choose which providers to focus on.
Decide on your ideal reply rate — that’s the percentage of emails that will get responses during the warm-up. Keep in mind that reply rates directly impact your sender reputation. To avoid triggering spam filters, you need to keep your reply rate at approximately 30%.
Time required for this step: 5 minutes
Snov.io Email Warm-up offers two automatic strategies you can choose from: Progressive and Steady. Here’s how they differ:
| Strategy | Best for | How it works |
|---|---|---|
| Progressive |
| Email volume starts low and increases gradually each day until it hits your warm-up goal. Example: Day 1 = 5 emails, Day 2 = 10, Day 3 = 15, and so on |
| Steady |
| The same number of emails is sent daily during the entire warm-up. Designed to stabilize reputation through consistent volume. |
Each strategy presupposes starting email volume, daily volume increase, and a daily sending goal. We recommend not exceeding 40 emails per day for a new account.
Time required for this step: 2 minutes
Now choose between an AI-powered content type or your own template for the warm-up.
If it’s your first warm-up campaign, we advise using the AI-powered message content type. With the hyper-intelligent Snov.io AI, you can craft unique, human-like email copy and generate realistic, same-thread conversations for safe and effective warm-up automation.
Time required for this step: 2 minutes
Look how quickly you got it done! Once the warm-up begins, you’ll start seeing emails labeled “snv” in your inbox. Just leave them as they are.
At this point, you can track your progress on the warm-up dashboard. Focus on the Deliverability metric; it’s a key indicator of your warm-up success. You’ll know the process is complete once deliverability reaches 90% or higher and your daily warm-up limit (sending goal) is achieved.
Sometimes, low inbox placement rates may be a problem with a specific provider. You can check it by running a targeted deliverability test. If it shows you have troubles with a particular provider, you can do a warm-up for this provider only and resolve the issue.
The algorithm is simple:
If you’ve already chosen and set the account for the warm-up, go to the Email providers setting and click on the “Choose providers” button.
You’ll see the list of providers to choose from. Pick the one or (several) for which you’d wish to warm up your account.
Your account will now exchange emails with others on the selected provider, helping improve deliverability and sender reputation.
| 📍Expert tip Want even a more effective warm-up? Use Premium sender pool to exchange messages only with business accounts. It mimics B2B communication, helping you:
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You’ve heard those horror stories: a company spends hours on crafting a perfect message, only for it to land in the spam folder — or worse, get blacklisted.
Still think you can do without automatic warm-up? Check out our expert manual email warm-up tips for building your sender reputation.
Before you start sending campaigns left and right, you first need to configure your account for a successful warm-up period. It should be:
Here are some tips on what to do next:
Email authentication is the process of verifying how legitimate a message is before it gets delivered. This helps prevent spoofing and phishing attacks, which are two of the main ways scammers try to bypass spam filters.
There are several authentication methods, but the most common are SPF, DKIM, and DMARC. In simple words:
By configuring all the above records, you can ensure that your campaigns reach their destination and aren’t accidentally flagged as spam.
→ Find more information on how to set email authentication in our SPF, DKIM & DMARC guide.
You’ll need it to know how many people opened your email, clicked your links, and replied. These metrics help assess overall engagement and show how effectively messages are being delivered.
Low open rates may indicate spam issues, while a lack of replies could signal your content needs some improvement. Tracking this data helps you react quickly, adjust your strategy, and maintain sender reputation.
To make it easy, install the free Snov.io Email Tracker Chrome extension. It provides real-time desktop notifications, tracks opens and clicks, and even logs recipient activity directly within your Gmail.
Subscribing to 10–15 different newsletters is a smart way of manually warming up an account before launching an outreach campaign. This will help to show your ESP that your new mailbox has incoming mail; it’s alive and functioning.
Some good options to subscribe to include Email Monday, Stacked Marketer, Marketing Examples, and The Daily Carnage.
And don’t worry about inbox clutter — with Gmail’s new Manage subscriptions feature, you can organize all subscriptions smartly in one place for easier review.
Collect a list of addresses that you know are valid. These can be addresses of your friends, relatives, colleagues, and business partners.
There’s no need to send them any marketing or sales content you’ve prepared for prospects. You can just say hello, write a friendly personal message, and send them any content you find interesting. Then ask the people to do you a small favor:
Plus, try sending messages to different domains: Gmail, Yahoo, AOL, Outlook, GoDaddy, etc. This diversity will show ESPs that your account is trustworthy.
| 📍Expert tip Sending too much too soon is a fast track to the spam folder. That’s why spacing emails properly is essential. We recommend starting with a schedule like this:
Plus, you can use Snov.io’s cold email campaigns tool to maintain a natural sending rhythm. |
The warm-up duration normally depends on several factors, including:
Some ESPs, for example, will wait weeks until they start trusting a new account. And the longer and harder you work on your excellent sender reputation, the more they trust you.
We recommend warming up a new account 30 days before you send the first campaign, as higher reply rates may raise red flags with ESPs.
Even for active accounts, you’d better run a warm-up process for at least two weeks. This helps gradually build your sender reputation and improves email deliverability.
Once you start sending campaigns, continue the warm-up but reduce the daily volume to 10–20 messages. This helps maintain consistency and ensures you stay within your provider’s sending limits.
With large contact lists, you may need even more time: we recommend an 8-12 week warm-up for such cases.
Getting started with your first manual warm-up campaign? The following email marketing best practices from our experts can help ensure a steady and effective process. 😊
It’s a bad, very bad idea to send hundreds of messages automatically within just a couple of days. If your engagement rate grows too fast, ESPs may suspect you of being a spammer. The outcome you know already — you may get the account blocked entirely.
There’s another extreme — sending your emails too rarely. If you do it once in a blue moon, you’ll hardly see the desired results. As a rule of thumb, aim at sending messages at least once a day. Such a schedule will make your warm-up process consistent.
With Snov.io Campaigns, for example, you can schedule campaigns so that they reach your audience regularly at a specific time.
Do regular checkups to spot and remove any inactive contacts (those who have not opened or clicked your emails in a while). And don’t forget to clean your lists of those who have unsubscribed or marked your messages as spam.
At Snov.io, we advise our users to do it every 3 months. With our Email Verifier, you can run the process on autopilot. No matter how many contacts you’ve got on your list, you’ll get it scrubbed in less than a minute.
With Snov.io, the entire process of extraction and validation of emails became surgically accurate, with a deliverability rate of well above 90%.
Growth Team Leader and PMO of Marketing at GrowthMachine
They’ll help you keep a finger on the pulse whenever it’s high time to improve your inbox placement. We recommend aiming for the following healthy benchmarks while you’re testing your deliverability:
If your results fall below these thresholds, it may indicate deeper issues that you should address before launching email outreach campaigns.
Tools like Snov.io’s Deliverability Test instantly provide detailed insights into domain health, inbox placement, and spam rates. You’ll also get a clear picture of what’s going wrong—plus personalized recommendations on deliverability improvement.
Analyze your sender reputation by using a tool like Sender Score. It will measure your reputation and provide a score from 0 to 100 (with 80+ being a great result). Higher scores, better sender reputation.
Warming up your email account isn’t just essential; it’s the foundation of a successful outreach. Without a strong sender reputation and high email deliverability, even the most impeccable campaigns can land in spam or get blocked.
Use the above cold emailing tips and warm-up best practices to gradually build trust with ESPs. Track key metrics like open rates, spam rates, and inbox placement, and maintain steady, human-like engagement.
To put the process on autopilot, use one of the best email warm-up tools the world knows — Snov.io. With this service, you’ll focus on those that matter most, while your emails are landing in others’ inboxes, with high deliverability and conversions.
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