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 certain 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: warm-up with business domains

Enable premium warm-up pool to warm up your account only with business email domains (instead of free domains). This better 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 during warm-up.

• Recommended: Set your warm-up reply rate to 30%. 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: Warm-up period

Set how long the warm-up should run.

Recommended warm-up period:

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

For a first-time warm-up, Snovio recommends running it for at least 30 days.

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 activity 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

For new accounts, use a gradual ramp-up to simulate human-like sending behavior. The number of emails increases over time until you reach your target limit.

Best for:

• First-time warm-up on a new account

• Re-warm previously used accounts after a period of inactivity

Recommended settings:

Starting volume: 2-5 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: 2 warm-up emails per day

The number of emails added to the limit each day.

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

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

We recommend up to 30-40 warm-up emails per day. Keep your total daily sends (warm-up + campaign emails) at 50 emails or less.

Warm-up emails are not counted into your sender account's limit, but they do count toward your email provider’s daily sending limit.

Steady warm-up

Choose Steady warm-up to rebuild sender reputation after spam issues and improve deliverability while your campaigns are already running.

Best for:

• Improve deliverability for accounts with low inbox rate
• Restore account's reputation
• Accounts already running campaigns

Recommended settings:

Emails per day: Set your Steady warm-up limit to your email account’s daily sending limit (or lower). Warm-up sends the same number of emails each day during the warm-up period.

For example, if your account previously sent 30 emails per day, set the warm-up to 30 emails per day.

If you’re running campaigns alongside warm-up, split your daily sending limit between the two. We recommend keeping your total daily sends (warm-up + campaign) to 50 emails per day or fewer.

Add email content

Specific template warm-up

The specific content type is best for active accounts that are already sending campaigns or have sent campaigns before.

Use the real email template you plan to send in your campaigns. Warm-up helps improve its deliverability before you start emailing real prospects.

Recommended settings:

• Add Spintax variables to make your warm-up more natural

• Enable Plain text mode to improve warm-up progress

• Add the same custom tracking domain you use for campaigns to improve deliverability.

Spintax in Warm-up

Spintax is a great way to improve warm-up progress by adding variation to your emails. For best results, add meaningful variations.

Using only synonyms in your spintax may not yield the desired results.

Bad Spintax uses

 

{Hi|Hey|Hello} — a simple change in the greeting will have little to no impact.

{Thanks|Thanks a lot} — micro-variations will have no effect.

I {want|would like} to talk — a rephrase that doesn’t change the sentence at all.

We {accelerate|turbocharge|10x} growth — adding hype synonyms to Spintax increases the risk of triggering spam filters.

Good Spintax uses

 

Openers (different sentence structure, same intent):

{Reaching out|Following up} about {your outbound results|reply rates}.

Noticed you are {hiring AEs|increasing SDRs}—thought this might help.

I work with {teams like|companies similar to} yours on {reply rate|meetings booked}.

Rephrase problem + value:

Recently helped {Acme|Company} {double meetings|reduce bounces by 35%}.

Seeing {low reply rates|slow pipeline} from cold emails? We help teams {improve replies by 20–30%|book more first meetings} by {clarifying ICP + cleaning data|fixing list quality + email copy}.

CTA:

{Happy to share a 2-min breakdown of what worked |Are you open for a quick run-down?}

If not the right fit, mind pointing me to {the right person|who does outbound}?

Monitor warm-up progress

View your warm-up progress and metrics in the statistics panel.

What to track in warm-up:

• Deliverability score (main success metric): the total percentage of emails that reached the inbox during the warm-up.

• Inbox placement over time: Review results in Two-week or Month views for clearer trends.

• Results by email provider

Under Most popular providers, you’ll see your deliverability by email provider. If you selected specific providers for warm-up, you’ll see results for those providers.

This helps you understand your reputation with each provider and the deliverability you can expect when emailing recipients who use them.

A warm-up is considered successful when your Deliverability reaches 90% or higher and your daily sending goal is reached.

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: Next steps

Run a deliverability check

Warm-up improves sender reputation, but deliverability also depends on:

• Infrastructure

• Content

• Sending behavior

• Domain health

Run deliverability tests to identify remaining issues before launching campaigns.