How to set up Email Warm-up to improve deliverability

This guide explains how Email Warm-up helps your emails reach inboxes.

• Add email accounts and configure settings

• Choose the right warm-up strategy

• Choose the right email content

• Monitor warm-up progress

• Manage active warm-ups

• Run Deliverability check

The email warm-up is a vital pre-launch phase. A proper warm-up builds trust with inbox providers and helps your emails land in the inbox.

Snov.io helps your outreach land in the inbox instead of the spam folder with the following warm-up features:

1) Bulk warm-up launch

Start the warm-up process for multiple email accounts at the same time.

2) Targeted email warm-up

Warm up email accounts from any provider and run targeted warm-ups to improve deliverability with specific inbox providers.

3) Premium sender pool

Warm-up runs automatically using a premium sender pool. You only need to monitor progress and deliverability results.

4) Built-in automated strategies

Choose warm-up strategies tailored for new email accounts or for accounts with deliverability and reputation issues.

How Email Warm-up works

Email warm-up improves deliverability by sending emails and receiving replies through a trusted network of real inboxes—both other Snov.io users’ inboxes and our managed inboxes.

During warm-up, Snov.io automatically moves emails out of Spam and marks them as read and as important to reinforce positive signals.

Together, these actions create consistent engagement over time, which helps build a stronger sender reputation.

Configure warm-up settings

Go to Email Warm-up and click Add mailbox to begin.

Sender accounts

Select one or more email accounts to warm up. You can start the warm-up in bulk for multiple mailboxes.

The number of email accounts you can warm up simultaneously depends on the number of warm-up slots available on your plan.

Email providers: Targeted warm-up

Choose specific email providers to run a targeted warm-up.

Targeted warm-ups help restore or improve reputation with specific inboxes and improve deliverability for recipients who use them. Learn more in this article.

If no providers are selected, the warm-up runs in general mode across all providers.

Premium sender pool

Enable premium warm-up pool to warm up your account only with business email domains instead of free domains. This recreates B2B communication and speeds up reputation growth.

Premium warm-up features are available on Pro plans. To unlock access, upgrade your plan.

Reply rate: Automatic replies

Set the reply rate — what percentage of emails should get replies.

• Recommended: 30%

• Maximum: 45%. Higher reply rate may look unnatural.

Replies have the strongest impact on sender reputation. Automatic replies during warm-up help build it more effectively.

Campaign deadline: Scheduled warm-up period

Set how long the warm-up will run.

• Recommended: 30 days for new accounts

• Minimum warm-up period: 14 days for accounts with prior sending history

Recommended warm-up period:

New domains and accounts

4 weeks of warm-up is recommended for brand-new domains or mailboxes before you start sending real outreach.

Existing mailboxes

2 weeks of warm-up if you’re reconnecting an old account after a break or solving minor deliverability issues.

Reputation recovery

6 weeks of warm-up for domains with serious deliverability problems or spam issues.

Schedule: Warm-up sending time

Define days and hours when warm-up emails are sent.

For best results:

• Match the schedule to your real campaign timing

• Use the same timezone and working hours

If no schedule is set, the warm-up runs throughout the day.

Choose a warm-up strategy

Progressive warm-up (automatic ramp-up)

Best for:

• New email accounts

• Old accounts with no recent activity

Recommended settings

For new accounts, use a gradual ramp-up to simulate human-like behavior. Emails are increased gradually until your target limit is reached.

• Starting volume: 5 warm-up emails per day.

This is the number of emails we’ll send on the first day of the warm-up. The maximum starting limit is 5 emails.

• Daily volume increase: 1 warm-up emails per day

The number of emails added to the limit each day.

• Daily sending goal: 30-40 warm-up emails per day

The final warm-up limit at which it stops increasing. The warm-up will continue sending this number of emails every day until completion.

Set the warm-up goal close to your planned campaign volume. We recommend up to 30-40 warm-up emails per day.

Once the warm-up is complete, you can shift more of your sending limit toward campaign emails.

Warm-up emails don’t count toward your Snov.io email account limits, but they do count toward your email provider’s daily sending limit.

For accounts in warm-up, lower the campaign limit so that warm-up + campaign emails don’t exceed 50 emails per day.

Steady strategy:

This strategy works best for restoring an account’s reputation and improving deliverability if it has dropped during active campaigns.

In a steady warm-up, the daily email limit remains the same throughout the entire warm-up.

Messages per day: Set the number of emails sent daily for warm-up. This limit should match or be close to the number of emails your account recently sent per day in real campaigns. Consistency in the volumes the account sends is positive for its reputation.

Example:

• If your account was sending 50 emails per day in campaigns and you paused the campaign, set the warm-up limit to 50 emails.
• If you want to keep the campaign active, split the total limit — for example, 25 emails for warm-up and 25 for the campaign.

Remember, the warm-up limit does not count toward your daily limit in Snov.io but does count toward your email provider's daily limit. If you add a warm-up on top of an active campaign with the same limits, you’ll likely exceed your provider’s daily limit. To avoid this, adjust your limits in the account settings accordingly.

Step 3: Add email content

In Email content settings, choose between the options depending on your warm-up goal.

Specific template

You can add your own email template that you plan to use in real campaigns. Warm-up will use this exact template to improve deliverability.

Because the same content is used, keep the daily warm-up limit lower—around 5–10 emails per day.

Repetitive content can look suspicious. To make the warm-up less repetitive, use Spintax.

You can insert spintaxes from the Variable menu in the Email content settings (it's available only in Specific content type).

Tip: Spintax adds variation that helps both cold emails and warm-up. For best results, use meaningful variations. Random simple phrases may not be effective and can even harm the warm-up progress.

• Bad Spintax uses

This option is best suited for the first warm-up of a new account or for restoring reputation after a period of inactivity.

AI-generated warm-up emails have unique content to avoid repetitiveness. To make them look less generic, we add manually pre-written subject lines and phrases.

AI-generated emails use plain text mode by default to improve warm-up effectiveness. If you add a custom tracking domain to warm-up, plain text mode will be disabled automatically because adding a link turns the email into HTML.

Step 4: Start warm-up and monitor progress

The emails sent during warm-up will be labeled with "wsn" tag in your inbox. Don't reply to or delete these emails — the warm-up process will run automatically.

You can monitor its progress on the warm-up dashboard and on your warm-up list.

The main metric to track warm-up success is Deliverability. It shows the total percentage of emails that reached the inbox during the warm-up.

To understand how the progress goes, review the report in a Two-week or a Month timeframe (selected at the top).

The warm-up has done its job once your deliverability reaches 90% or higher and your daily warm-up limit (sending goal) is reached.

Under Most popular providers, there is a breakdown by the provider. If you've selected specific providers for the warm-up, you'll see results specifically for them.

You'll get an idea of your reputation with providers and the deliverability you can expect when sending to recipients who use them.

Step 5. Review and manage active warm-ups

You can manage all active warm-ups from the Warm-up dashboard.

From this page, you can:

• View which accounts are currently warming up

• Pause a warm-up or mark it as completed

• Reactivate accounts that were paused or stopped

• Update settings/strategy and daily warm-up limits in bulk

• Preview warm-up progress and check each account’s overall deliverability score

Even if your deliverability score improves quickly, a proper warm-up still takes at least 2 weeks. Keep the warm-up running to continue building and strengthening your sender reputation.

After warm-up: Deliverability check

Warm-up helps build your email reputation, but many other factors also affect your deliverability.

Run deliverability tests here.