2020 Email Deliverability Guide

Change the way your email is delivered

After close to 50 years, email is still alive and thriving. It returns the highest ROI of any marketing channel ($42 return on every dollar spent), and generations Z to Baby Boomers prefer it for receiving messages from brands. However, email isn’t a set-it-and-forget-it machine—it’s a powerful program that requires time and attention.

Email success starts with your deliverability. Metrics such as clicks and opens are important to look at, but no email gets clicked or opened unless it gets delivered first. It doesn’t matter how much time, money, or creativity you invest in your emails if nobody ever sees them.

Improving your email deliverability isn’t a one-and-done challenge—it’s something you need to revisit regularly (which is why we release this new, updated guide every year). We’re here to make deliverability less of an ambiguous roadblock and more of a controlled conduit between you and your recipients. 

We want all legitimate emails to arrive in the inbox—and that’s what recipients want too.

Chapter 2: About this Guide

Twilio SendGrid’s Email Deliverability Guide is one of our most popular resources for all things deliverability. No matter what type of emails you send, all businesses have the same goal: getting to the inbox. This is where deliverability comes in. 

This annually updated guide provides email deliverability best practices developed from conversations with our internal email deliverability experts and industry stakeholders. This year’s guide is full of the latest tips and tricks to help your deliverability!

The 2020 Email Deliverability Guide includes updates on:

  • Gmail’s Prefix Preferences
  • Verizon’s Postmaster Data Feed
  • Responsive Emails & Accessibility
  • BIMI
  • AMP for Email
  • SMS

In addition to these changes, we have added new resources and links throughout the guide as well as new updates and insights from our internal Email Delivery Consultants.

As companies grow and become more ingrained in the lives of their customers, email continues to be the backbone of customer communications. Can you imagine Spotify, Uber, eBay, Airbnb, or any other web application functioning without email?

Nearly every essential (and often non-essential) customer communication is sent via email, including:

  • Product announcements
  • Monthly newsletters
  • Privacy and account updates
  • Legal notifications
  • Billing notifications
  • Password resets
  • New follower notifications

Email deliverability is the process of sending emails that arrive in your recipient’s inbox as intended. Get your deliverability right, and your messages will arrive in the inbox when and how you expect. Get it wrong, and your message could be routed to the spam folder or completely blocked by the inbox provider.

What’s an Inbox Provider?

Common inbox providers include gmail, yahoo, outlook, and hotmail. These providers offer users a secure place to engage with email by scanning the content of the messages to filter spam, as well as prevent phishing and other unwanted email.

To maintain consistent delivery rates, businesses need to constantly prioritize the health of their email program. This means properly establishing your infrastructure and authentication, maintaining a positive sending reputation, creating a great user experience, and adapting your program to meet new and changing regulations.

Unfortunately, most businesses only get serious about deliverability after they experience a major issue—once the damage is already done. With the right expert solutions, your deliverability issues can be fixed, but it’s much better for you and your recipients to focus on prevention rather than a cure.

Expert Services to the Rescue

If you’re already experiencing deliverability issues, don’t panic. If this guide, the knowledge center, and other resources don’t fix the problem, we have experts who can help. Clients who use our expert services see an average 97% delivery rate (12% over the industry average), a 6% increase in open rates, and a 9.3 out of 10 satisfaction score. Email is complicated—our experts can help.

Deliverability isn’t just a nice-to-have—it’s a need-to-have. Email returns an average of $42 for every dollar invested (the highest of any digital marketing channel), but that’s not even the most valuable part. Think about the critical emails your customers need to receive:

  • Password resets
  • Confirmations
  • Shipping notifications
  • Opt-ins
  • Receipts

If these emails don’t arrive, you’re not only losing sales. You’re losing trust. You’re losing loyalty. And you’re eventually losing customers and subscribers.

Deliverability and ROI aren’t some distantly connected concepts—they have an undeniable fiscal relationship. Even tiny improvements in deliverability can make a big impact on the success of your email program. Improving your inbox rate by just 1% means more customers are seeing your emails and can take action on them, leading to increased opens, clicks, and conversions. See how much deliverability could be costing your business with our free ROI calculator.

Getting into the inbox takes time and energy, but the struggle is worth it.


Will Boyd

Will has spent the last 7 years in the email delivery world helping senders get their messages to the folks that want them. When he’s not thinking about email delivery, Will is a vintage guitar collector, avid blues music fan, and amateur blues historian.



“As more and more mailbox providers implement machine learning technologies in their fight against spam, making sense of email deliverability will be more critical for senders. While these filtering systems are already very impressive in their accuracy, I predict they will get even more accurate from here. This means that senders will need to devote more thought and resources into what the signals from their email campaigns are really telling them.

Email is all about nurturing relationships. This can’t be done from the spam folder. Investing in deliverability is investing in the quality of your brand’s connection with your customers–and will pay off in more than just improved open rates.”

Chapter 4: Sender Reputation Breakdown

Your email deliverability is largely determined by your sender reputation. The better your reputation, the more likely your email will be delivered to your recipient’s inbox. Your sender reputation is determined by a wide variety of factors:

  • Recipient engagement
  • Email content
  • Spam complaints
  • Spam traps
  • Invalid email addresses
  • Blacklists
  • Domain reputation

Your sender reputation (like any great brand or personal reputation) is hard to earn, easy to lose, and takes time to build. It’s established by recipient engagement, email list hygiene, and other email best practices.

Check Your Sending Reputation

If you’d like to discover your sender reputation, check out 5 ways to check your sending reputation. Keep in mind, however, that these sender reputation scores are not the end-all-be-all for determining if your message will land in the inbox.

While several factors contribute to how inbox providers evaluate senders, the most important component to prioritize is recipient engagement—how your recipients are interacting with your emails. When your recipients are opening, reading, and clicking on your messages, inbox providers know that your messages are wanted.

Verizon Media Postmaster

In february 2020, Verizon media announced that they are rolling out new data feeds to give your email program all the information it needs to iterate and improve while protecting users’ information. These email deliverability and performance feeds plan to provide more meaningful and accurate placement and engagement data to help you understand the health of your email program better than ever before.

Recipient Engagement

It’s important to pay close attention to recipient email engagement. Opens, clicks, unsubscribes, and spam reports are all ways your recipients engage with your messages, but there are other types of positive and negative engagement that are harder to track. Depending on the inbox provider, they might track how many times a message is: 

  • Forwarded
  • Ignored
  • Deleted without being opened
  • Moved to another folder

Inbox providers use all these signals to evaluate every email campaign you send. You won’t know for certain which elements carry the most weight and which new engagement cues they’re taking into consideration (which is why we publish this deliverability guide every year).

For example, if your email campaigns are getting very low open rates, inbox providers may start filtering your future emails to spam because your recipients indicate that the email is unwanted. Or if you’re getting high unsubscribe rates, inbox providers might read this as another signal that you’re sending unwanted mail.

The Upside to Unsubscribes

Don’t take unsubscribes personally. Sending to an unengaged audience hurts your sending reputation, so your recipient is doing you a favor by unsubscribing instead of ignoring your messages or marking them as spam.

Email Content

Content includes the words, images, GIFs, templates, links, preheader text, subject lines, and from addresses you use in your emails. All of your email’s content either helps or hurts your reputation. To build a good reputation, you’ll need to send engaging emails that have a professional look and legitimate links.

If you’re not a designer, check out our free email marketing template gallery—it’s chock-full of plug-and-play templates you can use for just about any email use case. Watch our latest email design webinar to learn how to redesign these templates (or your own handiwork) to create simple, stunning emails.

Spam Complaints

A recipient marking your email as spam is the strongest negative signal to inbox providers. Spam complaint rates above 0.2% are considered high, and these levels can lead to poor deliverability. Some inbox providers consider spam rates even lower than .2% as high, which is why you should always keep a close eye on your spam complaints after each campaign.

Learning to listen to rather than fight against spam complaints is a key skill of advanced email programs. Read In Praise of Spam Complaints to discover what valuable lessons your complaints are telling you.

Spam Traps

Spam traps are old or unused email addresses that should never receive your emails. ISPs and anti-spam organizations also plant email addresses to catch spammers and list buyers. These could be email addresses that never signed up to receive communications (AKA recycled spam traps) or emails that haven’t been used recently (AKA pristine spam traps or honeypots, nicknamed by AOL), but each pose a threat to your sending reputation.

The presence of any of these types of addresses in your contact list is a sign that your list is not well-maintained. Avoid these spam traps by removing recipients that no longer engage with your emails or have gone long periods without engagement. 

It’s important to avoid purchasing, renting, or scraping email addresses, as those recipients did not sign up to receive your content and will likely provide little to no engagement. There are several ways to build a healthy, engaged contact list no matter the size or scale of your email program. Whether you’re looking to make slight tweaks to the way you engage with new subscribers or are ready to implement new tacticsour blog has you covered.

For more information on list maintenance, check out our blog Email List Hygiene: 5 Tips to Help You Keep Your Lists Clean.

What Is List Scraping?

List scraping or list harvesting is the process of using software or bot to crawl through different websites and find email addresses that can be added to your contact list. The problem with this strategy is that they (and their respective recipients) have no relationship with you or your company; this means that you shouldn’t be sending them any email. 

Only send your emails to people who have indicated an interest in your product or service, or have asked for your emails outright. Otherwise, you’re at risk for spam complaints and a damaged sender reputation.

Invalid Email Addresses

Continuing to send email to large groups of invalid or nonexistent email addresses is a big red flag for inbox providers and can damage your sending reputation. Reduce the number of emails sent to invalid addresses by immediately cleaning bounced email addresses from your active mailing address.

Build Your Email List from the Ground Up

Targeted display ads can drive interested parties to a landing page where you can explain the benefits of receiving your emails and collect their permission to send to them. Make the email process clear to the recipient everywhere you can. Selling the real value of the emails you send will help to build an engaged email list. Learn more about this tactic in our blog post What are Display Ads and How Can They Help You?

Abandoned email accounts can become invalid addresses, so removing long-term, non-engaged addresses from your list is a great habit. You can also gauge the use and validity of an email address by looking at a recipient’s engagement with welcome emails.

“One of the things I have to work on most often with my clients is updating their list acquisition methods,” says Ashley Ortiz, an email delivery consultant at Twilio SendGrid. “Rather than bringing over an old list, buying a list from someone, or scraping email addresses off social networks, senders need to create opportunities for people to provide their email addresses…legitimately.”

If you want to learn more about growing your contact list the right way, you can read our guide How to Grow Your Email Marketing List.

Avoid “Typo” Traps

Recently, we’ve seen “typo” traps become very common among senders. Avoid this trap by making sure your address collection methodology removes typos in email addresses (e.G. Local@gmall.Com vs. Local@gmail.Com) and double-checking that recipients interact with an opt-in or subsequent welcome message before including their address in email campaigns.

Twilio sendgrid’s email validation API catches misspelled, fake, or invalid email addresses to help decrease your bounces and increase your delivery rates.

Sending Confirmation Emails

The easiest way to avoid adding invalid addresses and spam traps to your lists or getting included on blacklists is to send confirmation emails to new recipients. This process validates their email and confirms that they want your messages. We cannot stress enough how problematic it is to rent, purchase, or scrape email addresses and how damaging that practice can be to a sending reputation.


Many inbox providers monitor blacklists to help determine which senders need to be blocked or filtered. Most blacklists will list your IP address or sending domain if they notice a high number of spam trap hits, spam or junk complaints, or a combination of both. You can avoid blacklists by sending relevant content to the recipients that have recently engaged with your emails.

Just because you’re on a blacklist doesn’t necessarily mean that your deliverability will suffer. Some blacklists have a much greater impact on deliverability than others. If you think you’ve been blacklisted, we recommend working with our Delivery Consultants to determine what to do next. If you’re interested in seeing whether or not you’ve been blacklisted, we think MXToolBox is the best free lookup option.

Domain Reputation

  • Your sending domain has a reputation associated with it, and it’s equally as important as your IP address’s reputation. If messages sent from your domain generate a negative response from recipients, it won’t matter what IP addresses the messages come from—they may still be filtered by inbox providers.
  • Watch your links to third parties—they could do more harm than good. Even if you’re doing everything else right, a single link to an unreputable website in the body of your email could prevent your message from getting to the inbox. Be sure you’re only linking to trusted websites and sources and, ideally, only those that you control.

Cousin Domains

Cousin domains are triggers for inbox providers. For example, let’s say that company.Com also uses company-mail.Com, companymail.Com, and companydeals.Com to segment different email streams. Those extra domains could negatively impact your deliverability.


Tom Emilio

Tom is an email marketing expert with a passion for deliverability and MTA technologies. Providing knowledge and expertise across a variety of industries, he’s been passionate about helping customers with their email programs for the past 8 years.

Gmail’s New Email Address Prefix Preference

Gmail continues to recommend that senders avoid mixing different types of content (marketing and transactional) in the same message. Gmail is encouraging the use of a different “from: header” based on the category or type of message, which is not a tactic that was previously publicized. For example:

  • Purchase receipt messages: receipt@example.com
  • Promotional messages: deals@example.com
  • Account notification messages: alerts@example.com

This just yet another layer of Gmail’s filtering.


All unsubscribes hurt your sending reputation, so avoid them at all costs.


Chapter 5: Infrastructure and Authentication

Infrastructure often refers to the IP addresses and servers you’re using to send email, while authentication refers to the validation techniques you use to show that email coming from you is in fact yours. Your email infrastructure is what goes on behind the scenes to ensure your messages get to your recipient’s inbox.

Properly configuring your infrastructure can make or break your email deliverability. We’ll walk you through the basics below to get you up and running. If you’re debating whether to build or buy your program’s infrastructure, reference Your Guide to Email Infrastructure – Build It or Buy It.

Setting Up Your Email Infrastructure With Twilio SendGrid

Twilio sendgrid makes account creation and infrastructure setup easy. Check out our step-by-step guide to learn the process of setting up your infrastructure and authenticating your email.

Dedicated IP Address

All email is delivered over an IP address. Inbox providers use your IP address to judge your sending reputation when determining whether or not to deliver your email to the recipient’s inbox.

If you’re a high-volume sender who wants to make sure you’re in complete control of your sending reputation, you’re going to need a dedicated IP address (or even a few addresses if you’re segmenting your email streams by type of email). Here’s why:

  • If you’re sharing an IP address with other senders, their poor sending practices could impact your deliverability. 
  • With your own dedicated IP address, you’re in full control of your sending reputation and the impact it makes on your deliverability. 
  • If you send over 100k emails per year, a consistent sending pattern could help you build a solid reputation on a dedicated IP address. You’ll also be able to take advantage of other services for improved email deliverability.

Sharing an IP address can be a great solution, especially if you’re a low volume sender sending less than 100k emails per year. In fact, if you’re fortunate to end up with a cohort of senders following email best practices, you could reap the rewards of a reputable IP address. However, many of Twilio SendGrid’s lower volume senders choose to upgrade their accounts to Pro so that they can claim the benefits of a dedicated IP.

Experiment With Segmentation

Effectively segmenting your emails could improve your engagement, and improved engagement will lead to higher deliverability rates. Try segmenting your emails based on timezone, engagement level, sign-up date, purchase history, or age. Segmentation can help you cater to the needs of various types of recipients. Read the essential guide to email segmentation for more ideas on how to segment your email.

IP Warmup

If you’re sending email over a new IP address, you’ll need to properly warm up your IP to ensure inbox providers deliver your emails.

Warm up an IP address by sending low volumes of email on your new dedicated IP and then slowly increasing the volume over time. This provides Internet Service Providers (ISPs) time to recognize, identify, and evaluate your sending practices to make sure you’re a legitimate sender.

IP warmup is used to ramp up your sending volume to your predicted “normal” levels. This will help ISPs understand your usual sending volumes so they can identify unusual or dangerous behavior. To learn more about IP warmup and tips for getting started, check out Twilio SendGrid’s Email Guide for IP Warm Up.

Email Stream IP Segmentation

Sharing a root domain across email streams (transactional vs. marketing) will combine reputations into each other. This can lead to deliverability issues if one of your streams is receiving more spam complaints or less engagement. To avoid potentially damaging your transactional email delivery, segment your different email streams onto multiple IP addresses. 

For example, you may want to send all your transactional emails (password resets, confirmations, notifications, etc.) on one IP address and all your marketing emails (newsletters, promotions, product announcements) on another IP address. This way, if your marketing emails are flagged as spam, you won’t encounter deliverability issues on your essential transactional mail.

The most basic separation is at the level of marketing and transactional messages. These mail streams often have very different reputations and must comply with CAN-SPAM differently. For companies with multiple brands, it may be wise to separate the traffic by IP for each brand, and then further separate the marketing and transactional mail streams under each brand to provide granular reporting and reputation management.

Win-Back on a Different IP

According to postmasters we’ve spoken with, win-back (or reactivation) campaigns often have the poorest deliverability and highest spam complaints of any mailstream. Consider an ongoing drip campaign of reactivation emails (just a few hundred at a time) instead of a large one-time reactivation campaign to keep the volume of complaints low. You might also consider using a different IP so that you don’t potentially damage your primary IP/domain.

SPF Record Creation

SPF stands for Sender Policy Framework. SPF is an email authentication method that identifies the mail servers that are approved to send email from a specific domain. ISPs use this validation protocol to determine when spammers and phishers are trying to impersonate your brand to send malicious emails from your domain.

When you publish an SPF record, make sure it lists all the IP addresses that will be sending email from your domain. While inbox providers generally don’t block email solely based on a missing SPF record, it’s one more data point that contributes to your positive sender reputation. Plus, it helps protect your brand.

DKIM Email Signature

DKIM stands for DomainKeys Identified Mail. DKIM allows you to publish a key that ISPs use to verify that the email message didn’t change in transit and the sender can take ownership of the content. DKIM defends against malicious modification of messages in transit, and it carries a lot of reputation weight with inbox providers. 

In 2020, messages not signed with a DKIM signature aren’t likely to see the inbox. Fortunately, Twilio SendGrid automatically signs all of your outbound email with DKIM. To learn more about how we implement DKIM at Twilio SendGrid, check out our DKIM docs page.

Automated Security and Your DKIM Signature

Twilio sendgrid will always provide you with a custom dkim signature, but your custom dkim signature will only automatically update if you select automated security when authenticating your domain. If you turn automated security off, you’ll be responsible for updating your dkim signature if you make a change to your sending domain.

DMARC Record Publishing

A Domain-based Message Authentication, Reporting & Conformance (DMARC) record is a protocol that uses SPF and DKIM to determine the authenticity of an email. The protocol allows you to specify how you want ISPs to handle emails that were not authenticated using SPF or DKIM. You can decide to send those emails straight to the junk folder or have them blocked altogether. Read our thorough post What is DMARC? to learn everything there is to know about the topic.

Brand Indicators for Message Identification (BIMI)

BIMI is the newest way for you to verify your brand in the inbox. Similar to SPF, DKIM, and DMARC, BIMI is a TXT DNS Record that lives on your servers. BIMI provides another layer of trust and protection by adding your brand’s logo next to your emails.

With your logo displayed, recipients will better recognize your emails in the inbox, building trust and helping prevent fraudulent activity. BIMI is still new, and currently Yahoo! Mail is the only inbox provider that supports this feature, but Google plans to pilot BIMI with Gmail in 2020. Get started by learning how to build and publish a BIMI DNS Record.

A Records and rDNS

A records point your domain to an IP address, while rDNS (reverse DNS) links an IP to your domain. Having these pieces in place is an important step in building trust between you and inbox providers. SendGrid walks you through generating these records in the sender authentication process.

Domain Authentication

Your sending domain needs to be able to receive email, and it must have a valid mail exchanger (MX) record. If not, some inbox providers will block your email. Twilio SendGrid’s sender authentication process generates these records for you. All you need to do is copy and paste these records into your DNS. We also recommend going one step further and making sure the full “from” address is an inbox that can receive mail (this allows a recipient to respond to that address and not get a failure message).

Watch the video at the end of this section to learn how to authenticate your domain with Twilio SendGrid.

TLS (Transport Layer Security)

TLS encrypts email while it’s being delivered. This prevents someone from reading the mail traffic as it moves between the sending and receiving servers. TLS has become a widely adopted security protocol to protect sensitive information and communications over email channels. Fortunately for you, Twilio SendGrid sends using Opportunistic TLS, establishing a secure connection (where available) on the highest encryption level the receiving server accepts.

Feedback Loops

Spam feedback loops (FBLs) are offered by most mailbox providers to let you know when recipients mark messages as spam. Immediately remove the addresses of spam reporters from your active email lists to maintain your sending reputation and the respect of your audience. Twilio SendGrid automatically integrates with all the major spam feedback loops to suppress email addresses of spam reporters.

“postmaster” and “abuse” Mailboxes

To access FBLs, many inbox providers require that you have abuse@ and postmaster@ email addresses. Monitor these mailboxes for complaints from inbox providers that don’t have FBLs so you can address any reports of unsolicited email.

postmaster@, abuse@, and a few others mailboxes are considered standard role accounts—sending anything other than abuse complaints to them is considered bad practice. You should consider automatically suppressing these addresses at any domain to ensure compliance with sending best practices. Learn more about role accounts in our blog post Role Addresses and Their Effect on Email Deliverability.

Two-Factor Authentication (2FA)

2FA is another layer of security protection you can add to your email account. If malicious users get access to your account, their fraudulent activity will very likely damage your sending reputation, even if you are able to recover from the hack. By enabling 2FA, you can make your Twilio SendGrid account more secure by requiring additional authentication beyond a username and password for logins. Watch the video below to learn how to configure 2FA on your Twilio SendGrid account.


Getting Started with Domain Authentication


Resetting your Password and Setting up Two-Factor Authentication



Will Boyd

Will has spent the last 7 years in the email delivery world helping senders get their messages to the folks that want them. When he’s not thinking about email delivery, Will is a vintage guitar collector, avid blues music fan, and amateur blues historian.



“To be honest with you, switching IP addresses is almost never the answer to your email deliverability problems. Switching IPs when you’re having deliverability problems isn’t fixing any of the underlying problems. If you get a new IP, but maintain poor sending practices, you’ll continue to have email deliverability issues.

Switching IPs, but continuing to send similar content from an existing domain is a tactic used by spammers and malicious senders. Inbox providers will see this and may block your messages at the gateway.”

Chapter 6: How to Maintain Your Reputation and Keep Your Recipients Happy

Now that we’ve covered all of the different factors inbox providers take into account when evaluating your emails, it’s time to look at the messages you’re sending. 

The actual messages you’re sending have a big impact on your deliverability and the ways that recipients engage with them. Below are some of our best tips for creating and sending email campaigns that engage and interest recipients.

Ask Permission and Respect It

Unlike other forms of marketing and advertising, email recipients have the choice of whether or not they open or even receive email communication. You are truly a guest in a recipient’s inbox. If you aren’t a polite and respectful guest (or if you wear out your welcome), you’ll get kicked out.

Be a Polite Guest

Be a polite guest in the inbox by asking for permission to send email, and then honoring the terms of that permission. If a recipient agrees to receive your weekly newsletter, you’re asking for trouble if you start to send them daily offers. For more insight on email etiquette and becoming a favored inbox guest, check out our guide email manners: a tale of two senders.

Verizon Media Group’s Postmaster Engagement Feed

Verizon Media Group announced in February 2020 that it is beta-testing a new, more comprehensive Postmaster Engagement Feed for its platforms, including Yahoo! and AOL. 

While we don’t know everything about how this new feature will work, we do know that it’s going to include a positive feedback loop in addition to the standard negative feedback loop. This means senders will have access to metrics such as, where an email lands in the inbox (e.g. primary, promotions, etc.), the length of time it took a recipient to read an email, and whether or not they skimmed the content. This is a really exciting update, and we can’t wait to learn more right alongside you.

Create an Email Preference Center

This goes hand-in-hand with being a welcome guest in your recipient’s inbox. An email preference center allows users to tell you exactly what types of email they’re interested in. The key to a healthy email program is sending email that people are interested in receiving. Take out the guesswork by asking your recipients exactly what they want and how often they want it.

Provide Options Sooner Rather Than Later

well-written welcome message helps set the tone for a new email relationship. Welcome messages should remind users why they signed up for your email program. This message should arrive as close to real-time as possible and detail what kinds of email the recipient can expect to receive from you and how often they’ll receive it. Welcome messages should also include unsubscribe and preference center links.

Send a Welcome Message

well-written welcome message helps set the tone for a new email relationship. Welcome messages should remind users why they signed up for your email program. This message should arrive as close to real-time as possible and detail what kinds of email the recipient can expect to receive from you and how often they’ll receive it. Welcome messages should also include unsubscribe and preference center links.

This welcome message from New York Times Cooking is a great example of a welcome message. It thanks the recipient for signing up and directs them to a few articles that may interest them. Toward the bottom of the message, they include a note that this is the first email in a series of 4, so expectations are clear from the beginning.

Stop Worrying About Gmail Tabs!

Gmail’s promotions tab is a third option outside of the typical “inbox” and “spam.” the promotions tab is not a commercial/promotional purgatory where messages are sent to float infinitely through the digital abyss. Email in the promotions tab is still regularly engaged with and checked. For more information about gmail’s tabs, check out our blog post, I fought gmail’s tabs, and the tabs won.

Test Before You Send

Before you send any emails, it’s important to test your messaging and content to know how it will perform and how it gets to the inbox. In December 2019, we launched our new Email Testing tool for Dynamic Templates to help our customers avoid common email mistakes and bypass spam filters. Even little mistakes like broken links can lead to a decline in your deliverability in the long run, so testing your content before you send is really important. 

For more information on our Email Testing program, check out our blog post Test for Success: Email Testing for Your Programmatic Sending.

Bundled Messages in Gmail Promotions!

Google has been working to improve the promotions tab for both marketers and subscribers alike. Recently, senders have had the ability to add “annotations” to promotional messages. Gmail, in conjunction with their machine learning, uses these annotations to provide recipients with “bundles” of messages most relevant to their interests at the top of the promotions tab:


If you’re a Gmail user, these bundles are likely already in your promotions tab. The annotations appear in message headers and highlight helpful information including deal amounts and expiration times. For more on how to utilize this powerful new feature, check out Google’s guide to annotations: Get started: How to annotate your email | Promotions tab.

Remove Unengaged Recipients

Sending emails to recipients who no longer engage with your messages damages your sender reputation for several reasons:

  • Addresses that don’t open or click on your messages are more likely to mark your messages as spam.
  • Unengaged addresses can become spam traps.
  • Unengaged recipients can lower your open rates, which make your messages and traffic look unwanted.

Let’s Talk Emojis

In our 2019 Email Benchmark and Engagement Study, we found that the use of emojis in subject lines can alienate some groups. Depending on the type of business or industry you’re in, emojis can be perceived as unprofessional, spammy, or immature.

Of all of the age groups we spoke to, Gen X and Baby Boomers disliked seeing emojis the most. Gen Z and Millennials are more evenly split, but both indicated that emoji use should make sense for the brand using them, rather than using them randomly.

As a sender, you know your recipients and customers best. If your audience tends to fall within the Gen X and Baby Boomer age range, consider skipping the emojis. If your recipients fall within the Gen Z and Millennial age range, try testing emojis in your communications and know that moderation is the key.

For more research on content preferences and their relationship with age ranges, check out our 2019 Email Benchmark and Engagement Study.

Make It Easy to Unsubscribe

Although it may sound counterintuitive, making your unsubscribe process as simple and clear as possible improves the recipients’ experience and can be good for your sender reputation. If a recipient no longer wants or needs to receive your emails and there isn’t an easy way to unsubscribe, they are very likely to report your content as spam or junk. Remember, someone who opts out can always opt back in, but a spam complaint can be detrimental to your entire campaign as well as your email deliverability moving forward.

Consider List-Unsubscribe

List-unsubscribe is an optional email header that allows recipients to remove themselves from a mailing list without clicking through an unsubscribe link or reporting a sender as spam or junk. If you implement list-unsubscribe, the major inbox providers will add unsubscribe links into the headers of your emails, which will allow recipients to unsubscribe without opening the message. Learn more about list-unsubscribe in our What is List-Unsubscribe? blog post.

Be Conscious of Your Sending Frequency!

If you feel like you’re doing everything right with your email program but are still landing in the spam folder, you should reassess your sending frequency. Between your regular newsletter, special offers or discounts, and other announcements, you may be sending more email to your recipients than you think. If you’re being filtered out of the inbox, even a slight reduction in the amount of email you’re sending to recipients can have a positive outcome.

In our 2019 Email Benchmark and Engagement Study, 54% of research participants said that if companies were to send them an email every day, it would weigh heavily into their decision on whether or not they unsubscribe from that mailing list.

One of the biggest annoyances reported in the study was receiving too many emails from the same sender throughout the course of a week. This irritation compounds when a company bombards the recipient’s inbox multiple times per day. Recipients also reported annoyance when emails looked too similar or felt repetitive. For more data on sending frequencies and consumer content preferences, check out our 2019 Email Benchmark and Engagement Study.

Allow Recipients to “Down Subscribe!”

Use your email preference center to your advantage by allowing recipients to “down subscribe,” aka allowing recipients to remove themselves from certain mailing lists or campaigns rather than removing themselves completely by unsubscribing. Learn how to do this in our blog, email preference center perfection.


Welcome messages should arrive in a new recipient’s inbox any time after opt-in.



Emily Thrasher

Inspired by their evolving industries, Emily specialized in digital communications for retail and entertainment brands until she decided to challenge her technical skills and dive into the SaaS world. She came to SendGrid and spent three years on our Technical Support Team where she worked directly with clients and partners, helping them leverage SendGrid to grow their businesses. She transitioned to our Delivery Consultant team in 2018 to continue guiding clients through their email program journeys.


I probably sound like a broken record on a lot of client calls, but a common theme among clients with deliverability issues is their sunsetting policy… or lack thereof.  I’ve seen companies sending their email campaigns to people who haven’t engaged in an email in YEARS!

Not only is this bad practice, but it’s also costing them money to store those old, unengaged email addresses. Get rid of them. If you have recipients who haven’t opened an email of yours in the last 30 days, it’s time to start saying goodbye. Slow down how often you send to them, and remove them if they still haven’t opened anything in 3 months.

Chapter 7: The Focus on User Experience in 2020

Recipient engagement is one of the most critical signals impacting your sender reputation. The inbox environment is evolving, and brands that evolve with it to prioritize the user experience will see more engagement, improved reputation, and greater deliverability. Here are a few things you’ll need to focus on in 2020 to enhance your users’ inbox experiences.

Mobile and Desktop Responsive

Now more than ever, your emails must be accessible on any device. According to our 2019 Email Benchmark and Engagement Study, clicks on mobile emails increased from 55.6% to 61.9%. This means that all of your content must be responsive and adapt to different device displays. That being said, recipients do still switch between computers and devices when checking their emails, with some users reporting a preference to click through links on a computer.


Getting Started with Domain Authentication

 So, how do you handle these needs for adaptation?

We recommend responsive templates. Responsive templates allow you to create emails that adapt to the unique needs of devices while maintaining great visual quality and consistency, no matter where an email is viewed. For more information on recipient preferences, check out Chapter 8: Elements of a Good, Successful Email in the 2019 Email Benchmark and Engagement Study. For more information about responsive templates, check out our Free Email Template Gallery.

Dark Mode

Dark Mode is a color scheme that uses light-colored text and icons on top of a dark background. The darker design decreases the light emitted by screens while maintaining the contrasting colors necessary for readability. This saves the device’s energy, relieves eye strain, and can reduce screen glare.

Recently, Dark mode has made its way into just about every app, browser, and device—and the inbox is no exception. In 2019, iOS Mail, Gmail, Outlook, and others announced support for Dark Mode. With so many users opting to use Dark Mode, it’s critical your emails still look great in this new environment.

Optimize for Dark Mode

Each inbox provider renders your html emails differently, but there are a couple of general best practices you can follow to make sure your email looks great regardless of the color scheme. First, enable dark mode in your email’s html and css. Second, optimize your transparent logos and images to look good with both light and dark color schemes—this is especially important if your png contains black text.

AMP for Email

Though AMP is still in beta, it’s a very hot topic in the email world right now. There isn’t much data out there yet on AMP’s potential uses, but here’s what we do know.

AMP is not going to be a one-size-fits-all solution for your email program; in other words, use it if it makes sense for your business and product, but only if you can use it correctly. AMP can be a double-edged sword. While it gives the sender more freedom to create interactive or dynamic content, there’s also a lack of control over the environment it exists in for email. Unlike a website where you have complete control over information and how it is presented, that is not necessarily the case for AMP. When you use AMP in an email campaign, you set up the dynamic content you want to use and then send it away, losing the control you had over the interaction. 

In the case of some businesses, AMP may be a great opportunity to include interactive carousels and changing/expiring content, but for others, it may make more sense to link to a website. If the use of AMP doesn’t benefit the recipient, consider using traditional linking instead.

Something to think about when considering the use of AMP is that it is currently only available on Gmail’s platform. This definitely limits its practicality and use at the moment, but if it gets picked up by other major inboxes like Microsoft and Yahoo! Mail, we may see AMP gain momentum in the industry.

While we don’t know much yet about AMP and how influential it may be, it is something we are looking to support. For more information about how we approach AMP, check out our SendGrid and Google AMP for Email docs in our Knowledge Center.


According to the last census, 56.7 million Americans (18.7% of the US population) have a disability. These disabilities range from hearing and vision impairment to loss of motor control. Imagine now that nearly 20% of your email list has some type of disability that makes engaging with your digital content a different experience. To improve the user experience for all your recipients, you need to create emails accessible by everyone.

Mozilla’s MDN defines accessibility as “the practice of making your websites usable by as many people as possible.” That doesn’t just limit catering to disabilities, either—that includes those with slower internet speeds, lower-quality devices, and other barriers. Better accessibility means better engagement, and better engagement leads to fewer unsubscribes and spam complaints. To learn how to make your emails more accessible, check out our Email Accessibility Design Best Practice Tips.

Deliver on Promises

Another way to improve engagement and reduce spam complaints is to deliver on your email promises. While technically legal, certain grey-hat marketing practices (like gimmicky subject lines) can spoil your recipient’s inbox experience. Here are a few best practices to help you deliver on your inbox promises:

  • Ensure your subject line and email content match: While clever, cutesy subject lines might get more clicks, try to avoid clickbait. Your subject line should be relevant to the content in your email. If not, recipients can quickly send you to the spam folder.
  • Send what you said you’d send: When a subscriber enters their email address to signup for your blog’s weekly digest, that doesn’t automatically give you permission to start blasting them with product announcements and sales. Only send the email you promised to send—nothing more, nothing less.
  • Honor your unsubscribes: When a recipient unsubscribes from your emails, remove them from your mailing list as quickly as possible. Failing to do so is a surefire way to earn yourself a spam complaint.

“Always deliver on that subject line promise quickly and easily. Don’t make [recipients] hunt around and try to interpret what you were alluding to in the subject line.” – Jill Guest, Manager of Customer Marketing Holiday Email: What to Know Before You Send

Communications Fatigue

While researching our 2019 Email Benchmark and Engagement Study, we found that recipients know exactly what they want from senders and will unsubscribe or report emails as spam if they are feeling communications fatigue from a sender.

We define communications fatigue (or more specifically, email fatigue) as the feeling senders get when they receive more emails than they want from a sender. This could happen for a variety of reasons; the recipient could have a change in interest, there could be a lack of access to an email preference center or even a change in your sending frequency.

Based on our research, recipients are much more likely to forgive their favorite senders for sending multiple or repetitive emails, simply because they like their content. So long as they are interested in your product, service, or content, they may be interested in higher rates of communication.

As a sender, you’ll need to identify these high volume recipients and determine how frequently they want to receive emails (once a day, once a week, etc.). 

Often, however, these high volume recipients are not the norm. For many recipients, receiving plenty of emails over a short period of time can be a turnoff and lead to deletion or unsubscribes.

The Study found that most recipients prefer to receive promotional emails once a week rather than daily. The small exception to this rule is limited offer deals.

You’ll also need to keep in mind your business’s collective communications with each recipient. While you may only send a recipient a few emails a week, keep in mind they may also be receiving SMS, display ads, LinkedIn InMails, and more from your brand. Too much contact on too many channels begins to feel like an invasion of privacy and a bit spammy—so make sure you approach your email with a holistic view.

Chapter 8: Privacy & Compliance in a World of Engagement

From Canadian Anti-Spam Legislation to the GDPR, global privacy trends are consistently moving to provide recipients with more and more control over how their data is used and the types of communication they prefer to receive.

In a global marketplace, most senders should be compliant with the strictest legislation that impacts their sending. For example, if you’re sending any email to recipients in the European Union, it’s best to make sure that all of your practices are compliant with the GDPR.

Global email compliance

Compliance, however, isn’t only about doing what’s required. In fact, compliance with these new privacy laws will almost always help senders receive better results for their marketing efforts. When you set clear expectations about how a recipient’s data will be used, and the types of communications they should expect from a sender at the point of address collection, those recipients tend to be much more engaged with the email they receive. Engaged recipients (who aren’t reporting messages as spam) are what inbox providers look to for guidance when deciding which messages to deliver to the inbox and which ones to block at the gateway. 

Think of user permissions and legal compliance requirements as an opportunity. Frame your approach to compliance with the recipient’s experience, and you may have more success getting your emails into the inbox.


In 2003, the United States Congress passed the Controlling the Assault of Non-Solicited Pornography and Marketing Act of 2003, or CAN-SPAM Act. CAN-SPAM slowed the influx of unsolicited emails the world saw in the early 2000s by creating restrictions on the way commercial emails are sent and giving recipients privacy and protection. CAN-SPAM remains in effect today. 

The FTC defines commercial email as any “electronic mail message the… purpose of which is the commercial advertisement or promotion of a… product or service.”  If your business sends commercial emails of any kind, CAN-SPAM and its legal requirements of commercial entities should be on your radar.

Under the CAN-SPAM Act of 2003, all businesses using email for commercial purposes must comply with these 7 elements:

  1. Do not use misleading or false information in email headers
  2. Do not use deceptive language in email subjects
  3. Clearly and conspicuously identify advertising messaging as such 
  4. Inform recipients of your business’s location
  5. Tell recipients how to opt-out of future communications
  6. Respect opt-out requests and handle them quickly
  7. Be cognizant of what third parties or others do on your business’s behalf

The biggest things to remember with CAN-SPAM are avoiding deception, clearly communicating the purpose of your email(s), and ensuring that recipients’ preferences are respected. More likely than not, you are already compliant with these elements. Remember, you must be compliant with the CAN-SPAM Act at all times if you send commercial emails.

General Data Protection Regulation (GDPR)

The General Data Protection Regulation (GDPR) is one of the most hot-button topics related to email in the last decade. If your business works within the European Union or with its citizens, the GDPR should be top of mind when developing your international email strategy.

The GDPR updated and replaced the EU Data Protection Directive (1995) and applies to the entirety of the European Union as the de facto standard defining how companies can use customer data.

GDPR outlines 7 principles relating to the processing of personal data:

  • Lawfulness, fairness, and transparency
  • Purpose limitation
  • Data minimisation
  • Accuracy
  • Storage limitation
  • Integrity and confidentiality (security)
  • Accountability

Under this law, EU citizens have more say over the ways organizations use their data. For those doing business in the United Kingdom, the GDPR is still in effect despite the UK’s exit from the EU.

The GDPR applies to all EU businesses, regardless of size or industry, that handle personal data, as well as any organization doing business in the EU where EU citizens’ data is involved.

GDPR compliance dominated conversations in the email world when it was put into effect. The importance of user privacy and compliance with international legislation are part of a larger, ongoing conversation that continues to evolve and adapt.

California Consumer Privacy Act (CCPA)

The California Consumer Privacy Act (CCPA) was passed in 2018, but will not be enforced by the California Attorney General until July 1, 2020. The CCPA grants consumers considerably more control over their data and how it is used, but only applies to businesses within specific categories.

Under the CCPA, consumers have the right to:

  1. Know “what personal information is collected, used, shared or sold” by organizations they interact with
  2. Delete “personal information held by businesses” which includes any of the business’s service providers
  3. Opt-out of the sale of their information
    • Consumers have the right to “direct a business that sells personal information to stop selling that information”
    • There are specific protections for minors as well:
      • Those under age 16 “must provide opt-in consent”
      • Those under age 13 must have a “parent or guardian consent” on their behalf
  4. Non-discrimination when exercising CCPA privacy rights, including access to “price or service”

Knowing this, here are the characteristics of businesses affected by the CCPA. Only one of the following needs to apply for your business to be affected.

Under the CCPA, businesses must comply if:

  1. The business’s gross annual revenue exceeds $25 million
  2. The business “buys, receives, or sells the personal information of 50,000 or more consumers, households, or devices”
  3. 50 percent or more of the business’s annual revenue comes from the sale of personal consumer information

Under new CCPA regulations, affected businesses must notify affected parties about data collection before or at the time of collection. Businesses must continue to comply with CAN-SPAM opt-out expectations in a timely and respectful manner, and also need to include a “Do Not Sell My Info” option to comply with the CCPA. Additionally, businesses must provide a response to opt-out requests or privacy setting changes, which can be fulfilled with a confirmation email. For more information about specific regulations and obligations, check out the California Attorney General’s Fact Sheet about CCPA.

Please note that compliance with CAN-SPAM and the GDPR do not ensure compliance with the CCPA. There are subtleties unique to each law that do not always overlap, so be sure to know how each law affects your strategy.

Chapter 9: SMS: A Complementary Channel of Communication

What Is SMS?

SMS stands for “short messaging service,” also known as a text message. SMS is a simple, but powerful, communication tool businesses and organizations can use to send promotional or informational messages via text.

Why SMS?

SMS messages, or text messages, have unmatched open rates, giving businesses the opportunity to communicate with their customers in a quick, reliable way. According to Twilio Learn, 9 out of 10 text messages are opened within the first three minutes of being received. 

Like email, SMS messages are delivered in seconds. Text messages can initiate two-way conversations and are easy to track. By using SMS in addition to email, you can provide your customers with an integrated and seamless communication experience. Plus, you’re giving them the option to connect and communicate on the channels they prefer.

SMS Deliverability

Over 5.2 billion people have access to SMS, including many people who lack a smartphone or broadband internet. While SMS is the most widely used application in the world, businesses today face challenges with implementing and scaling their SMS delivery programs. SMS deliverability measures the percentage of outgoing SMS messages that are received at their intended destination. SMS deliverability is critical for businesses that want to reach their audience through relevant, personalized, and timely messaging.

Whether you send a text message from a mobile device or an SMS API, there is a percentage of SMS messages that will never be delivered. As opposed to thumbing out a text on a phone, SMS messages sent programmatically through an SMS Gateway have an advantage—application logic can verify delivery.

There are many places where SMS delivery might fail, especially as messages move through the interfaces between pieces of infrastructure. Common causes of message delivery failure include invalid phone numbers, end-device level errors (like a handset being turned off), or problems with network connectivity. Other deliverability issues are deliberate, and messages reported by users may be blocked by carrier partners. 

It’s important to comply with state or local regulations and wireless carriers’ messaging policies to ensure SMS deliverability for both transactional and marketing messages. Wireless carriers have filtering systems to protect mobile subscribers from unwanted spam, fraud, or abuse. Filtering can range from a simple list of prohibited terms to advanced machine learning systems that adapt based on the messages passing through them.  

To reduce the risk of your messages being filtered or facing deliverability issues, businesses should follow these best practices for SMS messaging:

  • Get permission: Only send text messages to customers who have given you permission to do so. Request that your users opt-in to your SMS messaging via an online form or by asking them to text a particular keyword to a mobile number or shortcode.
  • Check your list: Ensure the phone numbers on your list are correct and can receive text messages. Invalid numbers (like landlines) are the most common reason for message delivery problems, and changed (or fake) phone numbers won’t reach their intended destination, decreasing your message delivery.
  • Don’t be spammy: Include clear opt-out instructions, precise language, and proper capitalization and punctuation in your messaging. Message your customers with relevant, time-sensitive promotions or information.
  • Use the right phone number: You can use either toll-free numbers or short codes—both support higher sending volumes and reduced filtering. Shortcodes are 5 or 6 digit phone numbers specifically made for mass mobile communications. Shortcodes are individually approved by wireless carriers so they won’t get blocked and can send at a faster rate than regular mobile numbers. Consider using a unique, brand-friendly shortcode for mass SMS messages. However, toll-free numbers and short codes aren’t available in every country.
  • Choose carefully: Choose an SMS provider that will provide helpful error code reporting and status callbacks so your business can diagnose any deliverability issues.

For more information on SMS best practices, check out our guide Using SMS and Email to Engage Your Customers

SMS is a universal communication channel that is meant to enhance, not replace, an existing email program. Just like email, SMS messaging should aim to keep recipients happy with valuable, relevant, and personalized information on the channels they prefer. To learn more about how you can add an SMS communication channel for your business, talk to an expert at Twilio.

Send With Confidence

Twilio’s programmable messaging API is equipped with features that allow you to send text messages with confidence. Our API lets you send and receive sms with shortcodes, engage in two-way conversations with your customers, and use images and attachments that are automatically optimized for mobile. To learn more about the API features and how twilio can improve your sms delivery, check out Twilio’s programmable SMS.

Email or SMS: Which Channel Should I Use?

SMS and email are complementary channels that can be used to create a seamless customer communication experience. You can use text messaging for short, time-sensitive communications; this means everything from appointment reminders to last-minute sale alerts. Use email to send more content and information to the place your customers are already going every day: the inbox. For more information about which channel is right for your message, watch our webcast A Perfect Match: SMS and Email.

Case Study: Yelp

Using Twilio SMS, Yelp meets its user base where they’re active: on mobile devices. Yelp customers can text their favorite restaurants to make, modify, or cancel their reservations. Businesses can easily update their customers on wait times, reservation availability, and reply to their texts straight from Yelp Reservations. Check out our case studies to see how other high-volume email senders are embracing Twilio SMS.

Chapter 10: Summary

Email delivery is an ever-evolving part of your program. As inbox providers’ preferences change, new rules and regulations get implemented, and new features become available, you have to continually adapt to keep your deliverability in tip-top shape. While there’s no magic bullet that’s going to get all of your email to the inbox, we believe that nearly every piece of advice in this guide can be boiled down to a single principle:

Send the right message, to the right person, at the right time, with the right frequency, on the right channel.

As a sender, you should be attempting to accomplish this with the following process:

  • The right message: Send the types of messages your recipients are expecting to receive with the content they want. 
  • The right person: Send email to people who have explicitly asked to receive it.
  • The right time: Send messages when your recipients are expecting to receive it. 
  • The right frequency: Don’t send too much email to your recipients or email them too frequently.
  • The right channel: Send on the channels appropriate to the message and audience.

In addition to this guide, SendGrid has created numerous resources that we update as often as possible to help you maintain a healthy email program:

Chapter 11: About Twilio SendGrid

We send emails for 82,000 customers (using over 2 trillion email addresses!) and have been in the email game since 2009, so we understand that email is the perfect combination of people and tech. We know that email can be the key to developing a successful business model, and we support our clients as they create meaningful campaigns.

No matter your background in the industry or role in your business, we know that your email needs are unique, and a one-size-fits-all solution won’t cut it. Twilio SendGrid provides customer communications solutions for every stage of your company’s growth because at the end of the day, it’s not only how we communicate, but why we communicate.

Start sending with us today.

Get Started with SendGrid

SendGrid helps you focus on your business without the cost and complexity of owning and maintaining an email infrastructure. And with a full-featured marketing email service that offers a flexible workflow, powerful list segmentation, and actionable analytics, all of your email needs are met in one simple platform.