Tips To Improve Stagnant Email Deliverability

One quarter of emails in the United States don't reach their intended recipients, according to a Return Path report that shows year-over-year email deliverability rates in 2015 fell as much as 4% worldwide to 79%, and by as much as 11% in the United States to 76%.

Despite the decline, SendGrid said Thursday it processed 225 billion emails in 2015, with a median delivery rate slightly above 98%. Considering that email’s high return on investment is impossible without the message first being delivered into a subscriber’s inbox, solving issues around deliverability is critical.

Victor Amin, data scientist at SendGrid, provided five recommended tips for increasing email deliverability rates in 2016 that marketers can immediately implement.

1. Quality Over Quantity

A simple opt-in feature guarantees your messages are being received by those who actually want to receive them, and properly formatted emails means they can be read. Poorly formatted emails, such as those with incorrect HTML coding, can also get caught in spam filters or may not render properly on mobile devices.

“Sending quality email that your subscribers want to receive is the basis of a great sending and brand reputation,” says Amin.

2. Consistency

Amin says email volume should be consistent and based on subscriber preference, since they are a key consideration for ISPs. High-volume senders are always a red flag, especially when volumes are inconsistent,” he says.

Email marketers should consider sending approximately the same number of emails each week or month instead of inconsistent sending sprees. This means marketers may want to plan ahead before big events that might cause email volume to fluctuate, such as corporate events or consumer holidays.

3. Reputation Matters

Are a high number of your emails being labeled as spam or junk? This could be negatively affecting your sender score and email reputation, and thus negatively affecting your deliverability rates.

“Even a tiny increase in complaints can cause your email to be blocked by the ISPs,” says Amin. “Keeping your complaint rate very low and less than 1% of mail that is sent and accepted by the ISP is very important.”

Email marketers should also steer clear of spam traps -- email addresses activated by ISPs to catch spammers. Sending just one email into a spam trap can instantly set back reputation scores and cause deliverability problems, says Amin.

4. Keep Up-to-Date With Contact Information

A good reputation is impossible without low bounce rates, and Amin recommends marketers implement procedures to immediately remove email addresses that are returned by the ISPs because the account is no longer active.

“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,” says Amin. “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.

5. Stay Off of Email Blacklists

An email blacklist, also known as a DNS-based Blackhole list, is a database of set criteria that help ISPs determine whether an IP is sending legitimate email or spam. There are several blacklists that all have varying criteria that could negatively affect deliverability rates, including Spamhaus and Barracuda Reputation Block List (BRBL).

“Appearing on just one of the leading blacklists is enough to get you blocked by some ISPs,” says Amin. “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.”

2 comments about "Tips To Improve Stagnant Email Deliverability".
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  1. Bill Kaplan from FreshAddress, Inc., January 14, 2016 at 5:32 p.m.

    Good overview of some of the key factors affecting deliverability but the deliverability rates quoted by SendGrid and by Return Path are likely comparing apples and oranges.  Return Path's report focuses on inbox deliverability, which has hovered in the 80% range for years.  SendGrid's deliverability rates most likely correspond to the percent of emails deployed that are successfully delivered, whether to an inbox or a junk, spam, or other folder.

    In general, most ESPs report on overall deliverability and these rates have hovered in the 98% to 99% range for most ESPs that only send to their clients' opt-in customer files.

    By far the most important criteria for maximizing one's email deliverability and inbox placement rates are the cleanliness and quality of the underlying list.  To this end, marketers should be sure to clean, correct, and validate the deliverability of every email address captured prior to entering these into their marketing databases.

    Fortunately advancements in technology, knowledgebases, and deliverability expertise have made this a simple and inexpensive task for marketers, provided they utilize an email hygiene, correction, and validation service to ensure these email addresses are SafeToSend.

    For more information on how the leading marketers, including 25% of the Fortune 100, build, clean, and update their email databases, see

  2. Erin M from SendinBlue, July 7, 2016 at 3:18 p.m.

    Thanks for sharing this thorough overview, Jess!

    My team (at SendinBlue) works hard to help email marketers optimize deliverability for marketing campaigns, automation, transactional emails. We've found that point #3 sending reputation - is one of the most key elements of deliverability. 

    Deliverability can be an intimidating topic, but it’s foundational for a successful email program.

    If you’re looking for a fun, engaging way to learn about email deliverability, check out this Marketing Profs post:

    How Is Reaching the Email Inbox Like Getting on Kanye’s VIP List?

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