IP warm up best practices What does it actually mean to “warm up” an IP address IP warming is the practice of gradually increasing the volume of mail sent via a
dedicated IP address according to a predetermined schedule. This gradual process
helps to establish a reputation with ISPs (Internet Service Providers) as a legitimate
email sender.
When an ISP observes email suddenly coming from a new or “cold” (i.e. recently
dormant) IP address, they will take notice and immediately begin evaluating the
traffic coming from that IP. Since ISPs treat email volume as a key determining factor
when detecting spam, it is best to begin sending a low to moderate volume (e.g. up to
1 million emails/month), eventually working your way up to larger volumes (e.g. over
1 million emails/month). This gives the receiving email providers a chance to closely
observe your sending habits and the way your recipients treat your email.
It should be noted that taking this gradual, ramping approach does not guarantee a
perfect sending reputation. It is still important to follow sending best practices.
Remember to always
‐ Send content that your users wish to receive
‐ Practice proper contact list hygiene
‐ Send email at a consistent and appropriate frequency
If you are sending too much or too fast from a new IP Address. ISP may "Delay" or
"Reject" your emails, So it's important to warm up your IP and gradually increase your
send rate through those IP address. which is also known as Throttling.
Warming Up Your IP Address The key to warming your IP address is to spread out your initial sends over multiple
days.
To know more about how your warm up schedule and how’s it going to be! We do a
simple calculation. (Assuming that your list hygiene is good low spam complaints, low
hard bounce ..etc) we give this example.ar34es
If you plan on sending 1,000,000 emails a day, we recommend that you split your
lists into small groups of no more than 10,000 recipients in each list. Email only one
group per day for 3 or 4 days, Then double up the volume for the next 3 or 4 days.
A cold IP with no sending history can send 2000 email per 24h safely! We divide
1,000,000 per 30 days! (The desired volume to send) we’ll have about 34,000 email
per day! 34,000 > 2000.. Its not safe! So we divide 34,000 per 30 we’ll get 1200 emails
per day 1200 < 2000 this is safe for the sending! So approximately to go from 2000
emails per day to 1,000,000 per day you will need an IP warm schedule for about 60
days.
If your bounce rate stays below 10% and your spam complaint rate stays below 0.1%
on those sends, you can safely double your send volume per day over the next few
weeks until your target sending volume is reached.
Number of emails per 24 hours per 1 IP address and its important to divide the volume to 24
hours.
Day #1
2000 emails
Day #2
2000 emails
Day #3
2000 emails
Day #4
3000 emails
Day #5
3000 emails
Day #6
3000 emails
Day #7
5000 emails
Day #8
5000 emails
Day #9
5000 emails
Day #10
8000 emails
Day #11
8000 emails
Day #12
8000 emails
Day #13
10k emails
Day #14
10k emails
Day #15
10k emails
Day #16
12,5k emails
Day #17
12,5k emails
Day #18
12,5k emails
Day #19
15k emails
Day #20
15k emails
Every ISP is different and no one publishes that information; some won't accept
more than X emails per hour, some won't accept more than X emails per minute.
Every ISP is different, but what is known, the slower you send the better your success
rate. Once your IP’s are warmed up, these initial rates adjust to allow greater mail
flow.
Email Deliverability Best Practices
Let's be honest: email marketing is nothing without deliverability. Don't believe
anyone telling you otherwise. If your email is delivered, it can be seen, read, and
clicked on. And if you can increase your email deliverability by even just 2‐3%, it can
significantly increase your ROI.
But considering smart filtering systems employed by mailbox and Internet service
providers, achieving high deliverability rates is not easy.
In the modern world, email deliverability is determined by sender reputation, bounce
and complaint rates, and recipient engagement.
To keep all these factors in order, you need to follow these four email marketing
practices:
1. Use Good List Acquisition and Management Methods Ideally, your email list must contain exclusively the email addresses of the
recipients who are engaged with your brand and want to receive your messages. In
the reality, email marketers often use poor list building and management methods.
However, it's important to strive for the "ideal" list because the quality of the email
list impacts deliverability tremendously. Mailbox providers monitor the email
addresses to which you are sending emails and will filter or block your messages
altogether if a poor list quality is determined.
Thus, to be on the safe side, consider the following best practices when it comes to
list building and management:
#1. Do Not Buy or Harvest Email Addresses. Buying or harvesting email addresses from public sources seems to be the easiest
and quickest way to populate the email database.
But it's a bad practice for these four reasons:
​
Unsolicited emails​
. If your recipients don't know who you are or never subscribed to
receive your mailings, your emails could look like spam to them.
After enough of spam complaints, your sender reputation will go down, and ISPs will
start filtering your emails. Even worse, you could have your IP landed on a blacklist,
ultimately making it harder for your future campaigns to be delivered to people who
actually want to hear from you.
Needless to say, sending to email recipients who haven't opted in is illegal in many
countries and violates the CAN‐SPAM Act.
​
Hard bounce addresses​
. You can't always trust the quality of a purchased list. You
don't know where those addresses came from, whether or not they are correctly
formatted and valid. The mailbox might have never existed, or has been terminated
by the mailbox provider, or abandoned by the end user.
Thus, purchased or harvested email lists are likely to generate a high hard bounce
rate. Mailbox providers ask senders to have low hard bounce rates because it shows
that you manage your email lists and keep them up‐to‐date.
Bounce rates above 10% will likely cause deliverability issues. Ideally, you should keep
your bounce rate below 2% to achieve a high Inbox placement.
​
Spam traps​
. Spam traps are email addresses that don't belong to active users and
are created and used by mailbox providers, anti‐spam organizations, and blacklist
administrators to identify spammers and senders using poor data management
practices.
When a mailbox provider sees spam traps hits from a particular sender, they question
the sender's list quality.
The type and age of the spam trap often influence the severity of verdicts placed on
senders who hit spam traps.
There are two types of spam traps:
Recycled spam trap​
: it is an email address that once belonged to a real person,
but was turned into a spam trap after being abandoned. Recycled spam traps
are aimed to identify legitimate senders with poor list hygiene practices.
Pristine spam trap​
: also called "honey pots," it is an email address set up solely
to capture bad senders and was never owned by a live person. It is assumed that
no one should send an email to such an address.
Many spam trap managers hide their spam trap addresses on websites, so only
harvester tools can capture them.
​
Bad statistics​
. This is obvious. Those people didn't want to hear from you, so what's
the reason for them to open and read your message. At best, very few of them will
open and click your emails. Are those few email clicks worth spoiling reputation and
future deliverability?
#2. Employ Good List Management Practices. Following are the recommendations for keeping hard bounce emails, complaining
users, and spam traps away from your email list:
1. ​
Quarantine new addresses​
. If you don't use a confirmed opt‐in process, don't
email new subscribers until you send a welcome message and do not receive a hard
bounce. This protects you from adding invalid addresses to your regular subscriber
base.
2. ​
Provide easy update/unsubscribe options​
. People often change email addresses
and may be willing to update their contact information with you. If you don't have a
full preference center, offer the option to change the email address at the point of
unsubscribing.
3. ​
Send regularly​
. As a rule, the less often you email your list, the more likely you
are to have high bounce rates. "Frozen" email lists are also more likely to produce
spam hits as old addresses may have been turned into traps since your last campaign.
4. ​
Monitor inactive users​
. According to the best email practices, a subscriber who
has been inactive for more than a year and has not responded to your re‐engagement
campaigns should be removed from your list. Set shorter "inactivity" periods of
six‐nine months if you send frequently and separate passive recipients from your main
list.
Note: do not delete inactive users forever. Just keep them separately and stop
sending email campaigns to them. Though they do not respond to your email
communications, you can always try to reach them through other channels, for
example, social networks.
5. ​
Scrub and validate your list​
. Regularly check your list for role accounts
([email protected]), obviously bogus addresses ([email protected]), and typos
([email protected]).
If you allowed your list to "freeze," consider checking it for validity before launching a
marketing campaign. Use desktop email verifier or online email validation services
like ​
BriteVerify​
or ​
DataValidation​
to determine invalid users on your list.
The most important metrics are:
​
Message is read​
– a positive indicator that the recipient wants to receive your
emails.
​
Message is replied to​
– a positive indicator that the message is desired and presents
a personal interest to the recipient.
​
Message is forwarded​
– a positive indicator that the recipient finds the message
valuable and thinks that others should see it, too.
​
Message is marked as "not spam"​
– a very strong positive indicator that mailbox
providers use to train their spam filters.
​
Message is moved to a folder​
– an indication that the recipient wants your email,
but also wants to better organize it and access it later.
​
Sender/domain is added to the address book​
– a positive signal indicating that the
recipient wants your emails and wants to make sure your future messages will be
delivered to the Inbox.
​
Message is deleted without being opened​
– a negative signal that your email is of
​
no interest to the recipient.
​
Message is marked as spam​
– a very strong negative signal that your email is
unwanted and is not worth to be in the Inbox.
This advice primarily goes from the fact that marketers often don't have the same
metrics as the mailbox providers. Most marketers can only see emails opened, clicks,
read, forwarded, bounced, unsubscribed and marked as spam in their own email
tracking reports. Thus, marketers are kept in the dark when it comes to other
important metrics like:
– how many of their emails were marked as "not spam";
– how many emails were deleted without being opened;
– how many emails were moved to a different folder;
– how many recipients added them to their address book.
Since these metrics aren't available to anyone, marketers and deliverability
consultants have to look at the disposable data: opens, clicks, and conversions.
Following are some best practices for keeping subscribers engaged:
1. ​
Build good relationships from the beginning​
.​
Set clear expectations, send a
welcome message, and then follow with what you've promised.
2. ​
Send engaging messages that look nicely on any device​
.​
Grab attention with
compelling subject lines, content that is easy to scan and capture the essence, and
offers that meet the subscriber's' interests.
3. ​
Send at the right time​
.​
Know your subscribers' audience and send messages when
they're most likely to see them and take action.
4. ​
Monitor engagement metrics​
.​
Engagement‐based metrics such as "deleted unread"
and "marked as not spam" provide a better way to understand Inbox filtering decisions
and determine whether engagement filtering is actually a problem. These metrics are
available today with data providers like Return Path.
5. ​
Re‐engage inactive subscribers​
.​
Develop a program to "wake up" inactive users
and get them back. Unfortunately, every email list sooner or later will contain
recipients who are not actively engaged. Re‐engagement campaigns can help senders
to recapture the attention of inactive recipients and not lose the list quality.
Because the recipients can become inactive for different reasons, you may need to
send different re‐engagement campaigns: special offers, access to exclusive content,
promotion of new content, videos, tutorials or "how‐to" tips, invitations to re‐opt‐in
or opt‐out, options to update email preferences or change their email address with
you.
If subscribers do not respond to any re‐engagement campaign, they should be
removed from your mailing list to protect yourself from hard bounces, complaints,
and spam traps.
Takeaways ● A good sender score is essential, but not the only factor affecting email
deliverability.
● Engaging content will improve email deliverability.
● List segmentation and content personalization will improve subscriber
engagement.
● Maintaining the list hygiene is not the only solution to ditch the spam‐traps.
● Replacing old IPs with new IP is not a great idea.
● Low complaint rate doesn’t always mean successful email deliverability.