IP Warm-up

Why IP Warm-up Matters

When you start sending email from a new IP address, major ISPs like Gmail, Yahoo, and Outlook have no sending history for that IP. Without a track record, these ISPs treat the IP as untrusted and will throttle or reject emails sent from it. IP warm-up is the process of gradually increasing your sending volume over days or weeks, allowing ISPs to observe consistent, legitimate sending behavior and build a positive reputation for the IP.

Skipping warm-up or ramping volume too quickly can result in emails being deferred, sent to spam folders, or blocked entirely — even if the content is legitimate and recipients want the emails.

Warm-up Schedule

EuroMail uses a fixed 30-day warm-up schedule with 6 progressive tiers:

After 30 days, the IP is considered fully warmed and sending is unrestricted.

How It Works

When warm-up is active on an IP, the SMTP engine enforces an hourly sending limit for that IP. As each day passes, the limit increases according to the schedule.

1. Emails up to the hourly limit are sent from the warming IP.
2. Overflow emails beyond the hourly limit are automatically routed to other IPs in your pool that are already warmed and have established reputation.
3. No emails are dropped — warm-up only controls which IP sends the email, not whether it gets sent.

This means you can start sending at your full application volume immediately after setting up EuroMail. The warm-up system handles IP assignment transparently.

Dashboard Monitoring

The dashboard provides a warm-up progress view for each IP in your pool (admin only):

• Current tier and hourly limit
• Days since warm-up started
• Bounce rate for the warming IP
• Pause/resume controls to manage warm-up manually

If bounce rates spike during warm-up, the system can step back to a lower tier to protect IP reputation.

Best Practices

Start with your most engaged recipients. During the first days of warm-up, send to recipients who regularly open and interact with your emails. Positive engagement signals (opens, clicks, replies) help build IP reputation faster.

Avoid purchased or scraped lists. Sending to unknown addresses during warm-up will generate bounces and complaints, undermining the warm-up process and potentially blacklisting the IP.

Monitor metrics daily. Check bounce and complaint rates in the dashboard throughout the warm-up period. Rates above 2% for bounces or 0.1% for complaints indicate a list quality problem that should be addressed before continuing.

Do not restart warm-up unnecessarily. If you pause sending for a few days, the reputation already built is retained. Only reset the warm-up schedule if the IP was blacklisted or if you need to start from scratch.