If you are sending emails from a new or “cold” IP address, abrupt spikes in email sending volumes can harm your IP’s reputation. To prevent this, you need to warm your IP address up gradually over time to establish your IP address as a legitimate email sender among Internet Service Providers (ISPs).
Properly warming up your IP address is a crucial step in building your email sending reputation and improving delivery performance. *If your database has fewer than 10,000 prospects, you do not need to warm your IP address.
Before Warming your IP Address
- Make sure that your SPF record is appropriately verified.
- Segment out your best and most active contacts. Don’t start your IP warming with old (older than 1 year) lists! Having high delivery rates with your initial campaigns will help build your IP’s reputation. See this article for help with keeping your lists clean.
Warming your IP AddressThe key to warming your IP address is to spread out your initial sends over multiple days. For example, If you plan on sending 40,000 emails a week, we recommend that you split your lists into at least four sublists with limit of no more than 10,000 recipients in each list. Email only one sublist per day over the first few days.
A good rule of thumb for larger ramp-ups is to start your sending at 10,000 prospects per day. Assuming your bounce rate stays below 10% and your spam complaint rate stays below 0.1% on those sends, you can safely double your sending per day over the next few weeks until your intended sending volume is reached. For example, if you want to send 200k emails a week, you should ramp up like this:
|Week||Emails Per Day||Total Per Week|
|Week 1||10k per day x 4 days||40k|
|Week 2||20k per day x 5 days||100k|
|Week 3||40k per day x 5 days||200k|
|Week 4||50k per day x 4 days||200k|
|Week 5||66k per day x 3 days||200k|
|Week 6||100k per day x 2 days||200k|
|Week 7||200k per day x 1 day*||200k|
*We recommend keeping your sending schedule at 50k/4 days to avoid having your emails throttled by recipient ISPs. Having a consistent mail volume from one business day to another is better than having a large volume spike on one day of the week and no email sent on remaining days of the week.
Monitor the bounce rates of your lists and stop mailing if the bounce rate of your first one or two sublists exceeds 10%. This is a sure sign that your list needs maintenance! Clean up your list, and then resume sending to the remainder of the sublists.
Doubling Established Mail Volume
Say you’ve already established your sending volume at 10,000 messages per week. What if you want to send to 20,000 a week now? We recommend that you increase your sending gradually over a month. See the below table for how to ramp email sending over a month from 10,000 emails per week to 20,000 emails per week. If Established Mail Volume is already at 10,000 messages/week:
|Week||Emails per Week|
- We do not recommend attempting to more than double your mail volume in a month on an active IP.
- If your mailing patterns are infrequent -- for example, only one mail campaign per month -- avoid sending more than 10,000 messages per day.