Email warmup is the process of gradually increasing the volume of emails sent from a new email address or domain to establish a good sender reputation with ISPs (such as Gmail, Outlook, etc.) and avoid being flagged as spam. Without proper warm-up, large-scale campaigns risk getting marked as spam or blocked entirely.
No Reputation Yet: New IPs/domains have a neutral or even negative “trust score.”
Spam-filter Sensitivity: Sudden spikes in outbound volume trigger alarms. ISPs might block or filter them.
Deliverability: A good sending reputation means your emails land in the inbox, not the junk folder. Warming up helps establish you as a trustworthy sender.
Manual — Sending a few personal emails each day yourself.
Automated — Using tools like E-Warmup.com or Seedlist.ai, etc.
Manual
You personally send a small number of emails to testers or colleagues.
Pros: Full control; tailor content.
Cons: Time-consuming; hard to scale.
Automated Tools (e.g., E-Warmup, Seedlist.ai)
These platforms auto-exchange emails among a network to simulate engagement.
Pros: AI-based, Automated, Hands-off, consistent.
Cons: Added cost.
Now let's talk about the benefits of an automatic email warm-up tool:
You don't have to do anything; everything is automated
Unique delivery control algorithms
Efficient warm-up thanks to a huge network of highly reputable email addresses
Automatic warm-up temperature increase communication of emails in a thread on the selected Topic
Communication of emails in a thread on the selected Language
Statistics and tests to track progress
Increase and maintain deliverability even during email campaigns with fast and high-quality support
Each provider has its own algorithms and parameters that determine it. For example:
Mailbox & Domain age.
Are SPF, DKIM, and DMARC parameters Pass or Fail?
Number of spam complaints;
The presence of an email address in the blacklists.
Number of attempts to send an email to non-existent addresses (bounced emails);
Spam traps;
Regularity of activity;
Content in outgoing emails;
Open rate;
Response rate;
And these are only the expected parameters that may differ and change for different providers.
It's worth mentioning that brand-new emails have a low reputation by default, which will prevent you from sending the 2,000 emails promised by G Suite from day one. The provider needs time to monitor your activity.
Warming up process
Today, it's not enough to just send out a daily rate of emails. To show email providers that you are an honest and legitimate sender, it is worth emulating the activity of a real user, namely:
Sending and daily increase of email limit
A large list of email addresses for interaction
Receiving emails
Reading emails
Mark as important
Replies to emails
Removing emails from SPAM
Using snippets (personalization of emails)
By following all the above points, you will minimize the chances that your emails will end up in the SPAM folder and teach providers such as Google, Outlook, Yahoo, Zoho, and many others that your emails should be placed in the "Inbox".
Here are the key benefits of email warm-up:
1. Improved DeliverabilityWarming up builds trust with email providers (like Gmail, Outlook, Yahoo), increasing the chances your emails land in the inbox, not the spam folder.
2. Builds Sender ReputationGradual, consistent sending with good engagement signals (opens, replies, low bounces) helps you earn a positive reputation tied to your domain and IP.
3. Reduces Spam Flags & BlocksJumping straight into high-volume sends without warm-up can trigger spam filters or get your IP/domain blacklisted. Warm-up helps you avoid that risk.
4. Ensures Better Engagement RatesStarting with smaller, targeted, and engaged audiences improves your open and click-through rates, which ISPs love to see.
5. Prevents IP BlacklistingReputation-damaging events (like mass bounces or complaints) during cold sending can land your IP on blacklists. Warm-up keeps your sender score clean.
6. Allows Safe ScalingWant to send 500 or 5,000 emails a day? Warm-up gives your infrastructure time to ramp up safely, avoiding sudden delivery issues.
7. Supports Long-Term Campaign SuccessConsistent deliverability leads to better reach, stronger customer trust, and more effective marketing over time.
Having explored both manual and automated options for email warm-up and deliverability, we hope this information helps you choose the approach that best suits your needs.