Understanding Email Deliverability
Today when sending an email campaign out the most important factor in deliverability is the reputation of your IP (a unique string of numbers that identifies your email sending domain), domain (the URL you are sending from Ex. xyz.com) and engagement with your emails. In the old days content filtering was the main method of determining whether an email was accepted or ended up in the bulk/junk/spam folder. Not anymore. When you hit "send" your email is transmitted from your outgoing mail server and then to the mail server at the receiving Internet Service Provider (ISP), which then decides what to do with your email based on a number of factors including: Sending IP reputation, authentication, your sending practices and recipient engagement.
This is a very complex process and is why, if you just start blasting out emails, you will get terrible results. To get high deliverability it's important to understand the factors that affect deliverability and systematically warm-up your email sending environment. Below are the steps you should follow:
Warm-Up Process Steps:
1) Domain Aging. If you're using a newly registered domain (ex. xyz.com) to send your emails, let them sit for seven days before sending a single email. You need to let age before using.
2) Major ISP Seed List Campaign. Your first campaign should be sent to a seedlist of 20-50 accounts at the big ISP's (Gmail, Hotmail, Yahoo, Outlook, AOL, Comcast, etc.) Next, take positive engagement actions with each email message such as:
- Clicking links
- Scroll to the bottom of an email
- Marking "not spam"
- Adding sender email address to your address book/safe sender list
- Forward email to others
- Move email message to another folder (not spam folder)
- Clicking to enable images
Repeat this process for at least a week, using different devices.
3) Scrub Your List and Remove Hard-Bounces. Before you start your "real" campaign, you must scrub your list to make sure there are little to no hard bounces (non-valid email addresses). Bad email addresses kill IP/domain reputation.
4) Throttled Email Warm-up Process. ISP's get suspicious when emails flood in from an unknown IP address, limiting or outright blocking their delivery. To mitigate this you need to go through an IP warm-up to help you build a good reputation. The primary goal of an IP warm-up is to ramp your sending volume to your anticipated "normal" levels. You want the ISPs to learn your usual sending volumes so they can identify suspicious behavior. At the end of the the warm-up period, you should be able to start emailing at a normal volume without risking your sender reputation. Yes, this process takes time in order to get to full volume, but negative results during this period will result in lower engagement and results very quickly. It's very hard to repair a bad reputation, short cutting the process isn't worth it. Warming up a new IP address can take 4+ weeks to ramp up volume, depending on the size of your list and a minimum of 30 days to establish a sender reputation.
Then refer to some of warmup schedules below
Warmup Schedule Examples:
100,000 email account. Sending on sloth with max 2 connections at a time per domain
Day 1: 20 emails
Day 2: 50 Emails
Day 3: 75 Emails
Day 4 120 emails
Day 5 250 emails
Day 6 500 emails
Day 7 800 emails
Day 8 1000 emails
Day 9 1300 emails
Day 10 1500 emails
Day 11 1800 emails
Day 12 2000 emails
Day 13 2500 emails
Day 14 3000 emails
Day 15 5000 emails
Day 16 7500 emails
Day 17 10000 emails
Day 18 15000 emails
Day 19 20000 emails
Day 20 25000 emails
30 million account warm up period. This is only valid if your data has little to no hard bounces. Any small amount of hard bounces can wreck ip reputation.
Day 1 1000
Day 2 2000
Day 3 4000
Day 4 7000
Day 5 11000
Day 6 18000
Day 7 24000
Day 8 40000
Day 9 60000
Day 10 90000
Day 11 140000
Day 12 180000
Day 13 220000
Day 14 300000
Day 15 500000
Day 16 650000
Day 17 800000
Day 18 1000000
Day 19 120000
Day 20 1500000
Important Deliverability Tactics:
- Keep the same "From Name" (firstname.lastname@example.org). This allows ISP’s to build up reputation for your brand name.
- Send at the slowest speeds possible in the beginning
- If you do not use your IP's at minimum of every 30 days you may lose of your email reputation or have the reputation reset. This is particularly important if you use multiple IP addresses, where some may be used and others may not be.
- Split large, non-time sensitive emails over multiple days
- If your bounce rate exceeds 10% stop mailing and clean your list
- If your spam complaint rate exceeds 0.1% reduce your volume and re-think your content
- Avoid spam trigger words and link shorteners
What to Expect
Your initial campaigns will have low deliverability and trouble reaching your list. During the warm-up process you can expect some bulking and blocking to occur. It is key to stick with the plan. Below are details of what you can expect and actions to take.
- Bulking at Yahoo, AOL, Gmail. Typically clears up after a few sends with solid positive metrics, but it can take time to get inbox delivery. The key is to keep sending to engaged subscribers.
- Delays at AOL, Microsoft and Comcast. The delays (421 bounces) will retry for 72 hours and if not delivered will bounce as a 5XX with the original 421 error in the bounce record. Delays are normal, and will lessen each day as reputation developes. As long as they are ultimately delivering there is no concern. However if they are timing out in large quantities you should back down your volumes to that ISP by tightening up your engagement
- Possible blocking by ISPs can occur if the list isn’t engaged enough. The key is to segment carefully and tighten up engagement Again the key is to keep sending.
- It is important to monitor your metrics and adjust the plan accordingly during the Warm-up period.