Steps to make sure you don’t land in spam/junk folder
Except DMARC, all others are configured at sub-domain level.
Verify SPF record
Verify DKIM record
Verify DMARC record
Configure Custom domain
Install SSL certificate on the custom domain (so that url becomes https instead of http)
Ensure that there is a redirection from http to https
Domain warmup (for new domains)
Don't send bulk/marketing email from the same IPs or DKIMs you use to send user mail, transactional mail, alerts, etc.
Each IP and sub-domain has a reputation, which can severely impact the delivery of your email.
By segregating your email according to function(transactional/promotional), you help ensure that your mail receives the best delivery possible.
General list of things to make sure
Regardless of where in the world you're sending your mail, make sure you adhere to the requirements stipulated by the CAN-SPAM Act.
The CAN-SPAM Act establishes requirements for commercial messages, gives recipients the right to have you stop emailing them, and spells out tough penalties for violations.
Don't use false or misleading header information or deceptive subject lines to hide, forge or misrepresent the sender or origin of the email.
When users subscribe to your mailing list, send them an email asking them to click to confirm their opt-in. This will improve the experience for users (who won't sign up accidentally or get signed up maliciously) and more importantly for your list (which won't contain uninterested people, fake email addresses, or most robots(honeypots)).
Support "One Click UNsubscribe", a method for signaling a one-click function for the List-Unsubscribe email header field. Refer to RFC 8058 for details.
Provide an obvious and visible unsubscribe process that doesn't require users to log in.
Sending email to users who are not reading them, or who report them as spam, will harm your delivery metrics and reputation. The best way to gain a dedicated subscribers is not by tricks but by great content.
Monitor hard and soft bounces as well as inactive recipients.
Consider sending a reconfirmation email to inactive subscribers periodically.
Things to keep a tap on your Domain reputation
Register your domain & sub-domain in the popular postmasters
Google (Gmail) - postmaster.google.com
Large volume senders should also register to Google Feedback loop, to identify campaigns that are getting high complaints from gmail users. It is mainly helpful for users who have a lot of brands in their account. Low volume senders will not benefit from it.
Yahoo - senders.yahooinc.com
High volume senders can also signup for Complaint Feedback Loop which tracks complaints at a domain level.
Check the reputation of your sending IP with SenderScore
Test your emails with - mail-tester.com - the best and it it is free for 3 tests a day
Steps to increase chances of landing in the Primary Inbox (in gmail)
not include this in subject line
not include this in from name and email id
Factors considered by postmaster for delivering emails
IP Address Reputation
SPF, DKIM Records
ASN (Autonomous System Number) reputation
When to use Dedicated IP Addresses
If your email sending is to the tune of 500k emails per month, it is recommended to have a dedicated IP address to send your emails. With that, you will need to do a lot of things that are beyond the scope of this post. Some of them include
Warm up your IP Address
Keep a consistent sending rate, no abrupt changes in emails sent
Publish reverse DNS (PTR) records
Have a FQDN in your DNS
Get certified to get into the allowlist of most email services