The first step in helping to ensure email deliverability is reputation. In the email world, sending reputation refers to a set of specific metrics directly related to your email sending practices. Senders with good reputations get delivered and senders with poor reputations get blocked at the gateway or their messages land in the dreaded “junk” folder.

A strong sending reputation, like a great brand or personal reputation, is built over time. In order to build a strong reputation, monitor and adhere to these 6 metrics and tactics:

1) Relevant, Properly Formatted Email: Sending quality email that your subscribers want to receive is the basis of a great sending (and brand) reputation. Ensure that your recipients want to receive your email by implementing a clear opt-in during the subscription process and be sure to send relevant and interesting content. Also, make sure your HTML is properly formatted—poorly coded emails get caught in filters or don’t render properly.

2) Consistent Volume: How much email do you send? Do you send approximately the same number of emails each week or month, or is your mailing schedule all over the map? Consistent volumes based on subscriber preferences are a key consideration for ISPs.

3) Very Few Complaints: Do your subscribers complain or tag your messages as “junk” or “spam”? Even a tiny increase in complaints can cause your email to be blocked by the ISPs. Keeping your complaint rate very low (less than .1% of mail that is sent and accepted by the ISP) is very important.

4) Avoid Spam Traps: Sending to even one spam trap or “honey pot” will instantly set back your reputation and cause deliverability problems. When you send to a spam trap (an email address activated by an ISP to catch spammers), it means you’re engaging in email address harvesting (an illegal practice) or your list hygiene practices are weak. Either way, ISPs aren’t going to deliver your email. Doing everything you can to avoid a spam trap is critical—keeping a clean list and not purchasing lists is an excellent start.

5) Low Bounce Rates: A good reputation also means that only a small percentage of your emails “bounce” back or are returned by the ISPs because the account is no longer active, the mailbox is temporarily full, or the recipient is out-of-office. If a lot of your mail is bouncing back, it means your subscribers aren’t engaged and you’re not keeping up to date with them. It also indicates that your list hygiene practices are not up to industry standards. This makes your email look like spam to an ISP and your email is unlikely to get delivered. Keeping your bounce rate low by implementing procedures to immediately remove email addresses that that are invalid is essential.

6) No Blacklist Appearances: Appearing on just one of the leading blacklists is enough to get you blocked by some ISPs. Senders with low complaints, who don’t hit spam traps, and who send email consistently generally don’t get blacklisted. However, if you do get blacklisted, having a good sending reputation will help convince the blacklist administrator to remove your IPs from their list. Read our recent blog post for more information on how blacklists work, how to find out if you’re on one, and how to get off one if you are.

Maintaining a strong reputation is only the first step to email deliverability success. To learn about infrastructure, authentication, content, and much more, download our free and updated Deliverability Guide.

Jillian Smith
As Twilio SendGrid's Sr. Director of Content, Jillian is responsible for ensuring that SendGrid provides valuable thought leadership content through the blog, whitepapers, webcasts, and more. When not writing and editing, you can find Jillian frequenting Denver restaurants in search of the best queso.