The advice and warmup schedule below is intended to be a suggestion only. Every sender is different and you may need email deliverability experts to help you determine the right warmup volume and frequency for your email program. How many emails you send during your warmup depends on your own total email volume, but you must send enough email at enough frequency so that ISPs can track your reputation.
— Most reputation systems only store data for 30 days, so you should not go 30 days or more without sending on any given IP. If you do, then you will need to warm it up again. —
Sometimes the hardest part of IP warmup is deciding where to start. First, choose a segment of your email list to warm up. ISPs recommend starting with internal addresses first, such as personal Gmail accounts. This is especially pertinent if you are building an entirely new reputation or trying to improve one that isn't performing very well. Some messages will probably be in the SPAM folder–and that's expected. Drag the messages out of SPAM and into your contacts/safe sender lists. That's why you start with internal emails. Replies to the emails are also beneficial for your IP warmup.
Next, start sending to your contact list. And choose recipients and mail streams who are "hyper-engaged." After you've gone through the most engaged recipients, move onto your recently engaged users.
You could choose your welcome message as your trial segment for your new IP. Welcome messages do several good things because these emails:
• Serve as a permission reminder
• Reiterate your value proposition
• Generate opens and clicks with their calls to action
If you don't have engagement data, use your most recent signups because users tend to be most active right after they sign up for an email list. As your reputation settles and your email volumes increase, work backward through your list adding older and lesser engaged recipients last. This is also a great time to scrub inactive or unengaged emails from your list.
If the new IP is underperforming (fewer opens, more blocks), be patient and consider slowing your volume acceleration, allowing your reputation to catch up. While warming up an IP can last up to 60 days, the majority of SendGrid clients warm up their IPs within 30 days–and some complete the process in as little as 1-2 weeks.
To determine frequency, use your delivery results as a guide. If you are attaining good email deliverability with high engagement rates, then you can try to speed up the process. However, if you get throttled, tap the brakes and slow it down.
During the warmup phase, pay close attention to your recipient engagement. The lower your engagement, the harsher ISPs will be on your warmup process. Take a look at your content and be honest with yourself. Are your subject lines clear and persuasive? Are you sending valuable content? If your initial segment doesn't think so, your entire list probably won't either.
Maintain Warmup Across all ISPs
Maintain a steady sending volume during the entire warm up period at EACH ISP. (i.e. Split up your warm up schedule so each ISP is receiving a comparable amount of mail each day—don't warm up Gmail on Monday, Yahoo! on Tuesday, etc.) If not, your sending activity appears sporadic and you won't be able to build a solid and dependable reputation.