The Email Deliverability Guide

Jun 6
35 minutes read
Getting your email marketing messages to your target audience is about more than just clicking send. It’s a complex process that relies heavily on your sender reputation, valuable content that engages your recipients, a contact list full of subscribers who want to receive your emails, and a robust interactive marketing delivery platform. But the most important part of this equation is without a doubt the reputation you build by following sender best practices.
The Cakemail Email Deliverability Guide: 7 steps to reach the inbox

The 7 steps to reach the inbox : A Guide to Best Practices for Email Deliverability
- By Kevin Huxham, Director of Deliverability, Cakemail Inc.

“If you take nothing else away from this paper, know that you have to earn a positive online reputation - but once you do, it can make the difference between your email getting delivered to the Inbox, the junk folder or not showing up at all.” - Kevin Huxham

This Cakemail white paper will look at best practices for email deliverability - arming you with the facts (in plain English) and giving you a list of dos and don’ts to ensure you hit the Inbox. Most of what you’ll learn amounts to a single golden rule: Send interesting and valuable content to people who have agreed to receive it.  

We’ll also cover topics like what’s required by law, how to build a great list, how to develop engaging content, and what happens after your campaign has been sent. All of this information is key to developing a good sender reputation - with your audience, with ISPs and with the anti-spam community.

At its simplest, successful email delivery consists of these seven basic steps:

Illustration 7 steps to reach the inbox
Follow these simple steps to reach your subscribers inbox

The Basic Delivery Model

Assemble the right list

The ideal audience wants to receive your email, has given you consent to email them and most important, is expecting to receive it. The list you send to should be targeted at a specific segment of your market and must contain accurate, current contact information and a working Unsubscribe. Ideally, this list will be an “opt-in” audience you have grown over time.

Create great content

No marketing campaign can be a success if the content isn’t well written, engaging and of value to the recipient. You know your audience best; now share content with them that they’ll want to read and keep them engaged. They signed up to your list for this very reason - don’t disappoint them.

Transmit the message cleanly 

Not all receivers are the same, not all of them can handle a zillion emails per hour like Gmail or Hotmail. You must respect delivery rates and comply with ISP guidelines - ensuring that the maximum number of messages reach your recipients’ inbox. Thankfully there are Email Service Providers (ESPs) out there like Cakemail that will handle a lot of this for you.

Deal with recipient issues 

If an ISP thinks your email is Spam, they will defer or block it very quickly. If an individual thinks your email is spam (or doesn’t recognize you) they will unsubscribe or worse - flag your email as “junk” and the more this happens the less of your email will reach the Inbox. Both of these issues can harm your reputation and should be dealt with in a timely manner.

Track the results

Every campaign has success rates that you can learn from, particularly if you’re looking at several messages against one another. A/B split testing allows you to look at the open and click rates you generate over time. This lets you discover trends in both content and the behavior of your list to allow you to better tailor future content and messages to help maximize Engagement.

Manage list hygiene

Recipient issues such as complaints, unsubscribes and hard bounces should update your list immediately to ensure that it remains clean. Emails that soft bounce repeatedly should be removed from the list, as should people who never register a click or open. At the very least, you should send an email to those who haven’t opened your emails or clicked links recently asking them to confirm that they wish to remain on your list. Maintaining a clean list is your responsibility and paramount to your continued success.

Fine-tune content

The results of a campaign should lead to improvements in future messages - meaning that you’re constantly optimizing what you send in order to maximize the outcome. You should always keep track of what time, what subject lines and what content had the best results.

Of course, each of the steps above is far more detailed than just what’s included in the list above. Some of the steps are the responsibility of marketers, while others are the job of an email marketing platform. The following pages break each of these steps out into more detail.

1. Assemble the right list

Every marketing campaign begins with a target audience. You can’t send messages to just anyone—you need recipients on your lists that have opted-in or have given their consent to receive messages from you. Without consent from your subscribers, the email you send them can only be classified as Spam.

The right list has to follow specific rules:

  • It must have appropriate consent. Recipients must have agreed to receive your message, either because they opted in to a mailing list, signed up for a newsletter, or agreed to get content from you. 
  • It must be up to date. People abandon emails, people lose their jobs, people relocate, companies fold, people die.. so just because somebody confirmed their email with you last year doesn’t mean that address is still going to be valid. If an email bounces because the address is no longer valid, it should be removed from your list.
  • It must respect a recipient's right to change their mind. If someone has opted out of a mailing list, they must be removed and not receive another message. If you have the same contact in multiple lists, you should think about including a Global Unsubscribe to remove them from everything. 
  • Ideally, you should be whitelisted by recipients. You should always encourage recipients to add you to their Contact list, Address book or to their Approved “Safe” Sender list to alleviate content filter issues and help establish you as a “trusted” sender. Most ISPs provide their users with several ways of doing this. For example, if the user clicks any of the following after opening your email: mark this sender as safe, enable images from this sender, never send email from this sender to my Spam folder, add sender to my contact list, etc. 

Having an existing business relationship with someone doesn’t mean it’s okay to add them to your mailing list. If you are adding people automatically, or the sign up process isn’t crystal clear, many of your recipients will flag your email as Spam simply because they don’t recognize you or never wanted to receive  your email to begin with. Try giving these people the option  to sign up when the purchase is made instead of doing it automatically. 

Complaints are the largest factor to  influence on your reputation so it is in your best interest to do everything you can to avoid recipients clicking the Spam button. To avoid complaints you should:

  • Never use a purchased, harvested or “scraped” list of any kind
  • Make sure you have a direct relationship with every single address on your list
  • Start confirming new signups (using a confirmed or double opt-in process)
  • Ask people if they want to be on your mailing list. DO NOT sign them up automatically
  • Make your signup process clear, explaining what someone is signing up for, when they will start receiving emails, and how often they can expect to hear from you
  • Use a consistent From name and email address
  • Use a subject line that truthfully describes the content of your email
  • Honor all opt-out requests in a timely manner
  • Abide by the rules of CASL, CAN-SPAM, GDPR or other Anti-Spam Legislation in your region
  • Keep your list current and up to date
  • Never reactivate old/invalid addresses
  • Send to your list on a regular basis

If you comply with all of these rules, you’re already off to a great start. To make things even better you’ll want your list to be engaged by sending content people look forward to receiving.

Subscriber consent 

The best mailing list is one filled with people who’ve requested that you send them something, but this can be done several different ways:

Confirmed “Closed-loop” Double Opt-in 

When someone signs up for your mailing list, a confirmation email is sent to their email address and an action is required (like clicking a link) in order to confirm that the address is valid. It is highly known throughout the industry as being the most effective method of growing your list as only the true owner of the email address can sign up and confirm their subscription. Not only does this method generate the fewest number of complaints, it also prevents you from adding invalid “typo” addresses and/or Spam “traps” to your list as they will never click the link to complete the confirmation process.

Notified Opt-in 

This type of opt-in sends a Welcome email to new subscribers upon sign up, but does not require any additional confirmation from them in order to be added to the list. This type of opt-in is a popular method, though it can be prone to abuse and lead to lists with more complaints than a two-step Double Opt-In process. 

Single Opt-in

Single opt-in is when someone knowingly signs up to a mailing list by checking an empty “Yes, please sign me up to receive news from company x” box when submitting a form (like an online shopping cart, or account registration for a particular website) but no confirmation email is sent. Although better than the Opt-Out method we’ll talk about next, this method leaves list owners open to abuse and generally results in a higher Spam and/or Bounce rate that can lead to delivery problems.

Opt-Out (Implied consent) 

Opt-out list building occurs when an email address is added automatically and users are required to either unsubscribe upon receipt of an email or to uncheck a box when submitting their data on a form, or as part of a checkout process. Using Opt-Out methods as a way to build your list is a bad marketing practice and can make recipients feel as if they were tricked, damaging your relationship and reputation in the process. This method typically generates a large volume of emails flagged as Spam which negatively affects your reputation as a sender and in turn your delivery rates. A popular method particularly at checkout,  but if you are using this method you would be smart to switch to Double Opt-in. 

Affiliate lists

Affiliate lists are the results of one company sharing an email address (or a list of addresses) with other partners or affiliates. If a person signs up to receive email from Company A, they should only receive emails from Company A. If they also receive email from Company B, because they signed up with Company A, they are more likely to complain. Often this will appear during a signup process as something along the lines of “Yes, please send me information from Company A and relevant partners”. This method also generates a lot of complaints and is prone to ongoing delivery problems. 

Purchased Mailing Lists 

Purchased Mailing Lists are lists of email addresses that have been bought from someone else for a price. Many companies contemplate buying lists as a means of building a mailing list quickly, but consent is not transferable and these types of lists are a marketing worst-practice. Not only have subscribers on that list not opted in to receive emails from you, they are likely going to flag your email as Spam, and you have damaged your marketing relationship with the receiver before it has even started. This will also directly affect the delivery of your existing clients that have opted in to receive these mailings. If you are using this method, you will find many ESPs will refuse your business. 

Rented Mailing Lists 

Rented lists are similar to purchased lists, in that the sender has no relationship with the intended recipients and are usually used for a one-time mailing to help grow your list quickly. Often the marketer never sees the list, but simply provides the content and is at the mercy of the list owner to send the message on their behalf. This can result in a high bounce and/or complaint rate and the reputation being tarnished is shared between the list owner and YOU (the sender). The recipients may also learn that you’re adopting bad marketing practices. 

Regardless of who sends the email, if the content is yours, you’re responsible for what others do on your behalf: the Federal Trade Commission (FTC) says that “even if you hire another company to handle your email marketing, you can’t contract away your legal responsibility to comply with the law.“

Harvested Lists

This technique is employed by spammers who acquire email addresses by harvesting or “scraping” them off the Internet. They search for anything that resembles a valid email address (like or run Directory  “Dictionary” Harvest Attacks that find valid addresses using a process of trial & error. These attacks are more effective for finding email addresses of companies since they are more likely to have a standard format (i.e.,,, No one on a harvested list has opted to be there or has a pre-existing relationship with the sender. Harvested lists generate a high volume of complaints, a lot of bounces and very poor email deliverability. 

Important Note: 

Using a Harvested, Purchased, Rented, and/or Affiliate list is a bad marketing practice and a violation of the Cakemail Anti-Spam Policy.

Illustration List quality vs relationship
This graphic shows the various degrees of list quality based on how lists are populated. 

Spam Traps

Spam trap addresses are email addresses that  exist for the sole reason of catching Spam. 

“The term “trap” is very appropriate in that these addresses are scattered throughout the internet to catch people either not using proper list building practices, harvesting emails, purchasing lists from a 3rd party, or marketers who have poor list hygiene (whether they know it or not).”

These traps are kept secret to protect their identity and are released to no one because making them public would render them rather useless.

There are two types of Spam traps: 

“Honey Pot” or “Planted” Traps:

These email addresses have been intentionally created to trap spammers scraping the millions of websites on the Internet for any address they can find. These traps are never published and do not belong to a real person thus could never “opt-in” to any list since it is impossible for the address to initiate, respond or give consent to having received email of any kind. Sometimes referred to as a “honeypot” or “planted” address, they are used by Anti-Spam groups, monitor and collect Spam. If you send an email to one of these traps, you will get exposed for using illegal marketing practices and you could get blacklisted which will seriously harm both your delivery and your reputation. 

Dormant” Traps:

These are usually addresses that have been deactivated for a period of time (sometimes as little as 6-12 months) and are used by receivers to judge the quality of your list. These addresses no longer receive email except to catch Spam. Sending to a “dormant” trap address will not usually result in a blacklisting because these addresses may have opted in to your list at some point. It does, however, raise flags because you are sending to an email address that is out of date and indicates that you may not be processing and removing bounces properly.  

“Sending to spam trap email addresses will affect your reputation and delivery over time.”

What can you do?

  • Never use purchased, rented or affiliate lists
  • If you’re not already, start confirming new subscribers using a double opt-in process 
  • Keep your lists up to date by removing people who complain or unsubscribe
  • Send emails to your list on a regular basis and remove non engaged contacts
  • Make sure you are processing hard bounces correctly
When changing providers, make sure you do not transfer any previous hard bounces or unsubscribes from your current list. Addresses that have previously been marked as invalid could potentially be turned into trap addresses and sending to someone who has unsubscribed (even by mistake) is illegal.”

List Segmentation

Segmentation refers to creating small groups out of a larger one – so taking your one big list and turning it into a number of smaller lists based on certain criteria. The criteria could include demographics (age, gender, education or others) or could include things like buying behavior, memberships, or any data that users submit when subscribing to a list, what pages they visited on your website, what they clicked on and more.

“While it may be tempting to build one list and email them all with a single message, there is tremendous marketing value in segmenting your list.”

Once you have this sort of data in a large list, it’s easy to create categories of subscribers. While you can still email the full list with a single message when merited, you can also now send an email with targeted content that appeals directly to certain segments of your audience. Do you want to target a specific country, region or  language?  How about those that made a purchase within the last six weeks? Segmentation makes that possible (and it’s easy too!). 

Targeted Content

Innovations in email marketing give you more power than ever before to send targeted, personalized and better yet, dynamic emails to list members. The more specific and targeted your message is to each recipient, the more likely you are to see success in your campaign results – whether you measure results in opens, click-through, or even revenue generation. 

With Cakemail, it’s easy to create targeted content and send messages in multiple languages, or alter the message based on how long someone has been on your list, what their personal preferences are, or based on past behaviors like opening or clicking on links in previous emails you’ve sent them.

2. Create great content

More than anything else, great email content engages and informs the reader. It should also encourage the recipients to open or  click . Something as simple as using a short, intriguing subject line or familiar term will entice them to want to read more and gives them a clear indication of what to expect. 

In addition, great content also follows certain guidelines:

Personalization is key

The more a recipient knows the message is directed at them, the more likely they are to open and read it. Personalization of content is one of the most significant factors driving interactive marketing conversion rates. It may be as simple as a “Hi Joe,” instead of “Hello Customers,” or can be much more sophisticated such as “Happy Birthday Joe!”

Reflect your brand, and reinforce it

You want your recipients to know that the message is from you—not from a third party. If a recipient doesn’t recognize you (the sender), they are more likely to unsubscribe. Worse, they may flag your message as Spam, making it harder for subsequent messages to reach those who want to receive it. 

  • Ensure you always reflect your brand well with legitimate “From” names and a valid reply address that is monitored by a real person. 
  • The domain used should also have functioning abuse@ and postmaster@ addresses as well as point to a valid website. 
  • Use custom templates that include your logo or other recognizable images that will make sure your recipients know it’s really you. 
  • Always have a clear call to action that results in them clicking through to something specific on your website. 

Comply with the law 

Anti-Spam laws define the essential requirements of what email messages need to contain, and you must follow those rules. For example, your messages must have a working opt-out/unsubscribe mechanism, and include a physical postal address of the sender. See the section later in this document on CASL, CAN-SPAM and GDPR Compliance for a complete list of requirements. 

Watch your HTML 

Did you know that Spam filters also scan the HTML code of your emails? 

  • Optimize your code before sending it, a
  • Avoid using too many Spammy words (Free!! Save big, Credit, etc.. )
  • Have a good balance of images and text
  • Use alt-text to provide context when images are not displayed.
    Most providers will only display images from senders they know or deemed safe by clicking “Display Images” or “This is a Safe sender”

Choose your formatting wisely 

Avoid using large fonts, bold text,  ALL-CAPS in your email object. Doing so can make your emails look like Spam.

Clear & Concise Subject Lines

Your subject line should be a compelling short piece of content that prompts your recipients to open your email and read more. This is particularly true if your target audience uses mobile devices, where screen real estate is at a premium. 

“Test your content on desktop and mobile versions before sending it so you know exactly what it looks like.”

Stay consistent

Content may be a single message, or it may be a series of messages (such as an ongoing newsletter or a drip campaign). If your communications with your audience will be recurring, then they should follow a structured theme and have consistent branding which will help establish familiarity and trust.

Find inspiration

Doing a bit of competitive market research can also provide you with creative ideas on  what works with particular markets, along with some great do and don’t moments you can learn from.

“Seeing some “best-in-show” content from others can be a source of inspiration and give you some great ideas on how email marketing can really be done well.”


Lastly (but definitely not least), make sure you’re using the right language and terminology, and you’ve double-checked spelling, grammar and punctuation before you hit send.  A 2nd set of eyes proofreading your work is nothing to be ashamed of. 

Here is your content checklist:

Checklist to download and complete
Download and follow this Email content checklist to improve your content!

noreply@ Email addresses

While the From name and email address might seem like small details, they can make a huge difference to the success of your campaign. By sending an email with a From address such as ‘’ you are sending a message to your customers and it’s “Please don’t talk to us”. 

“From” addresses like noreply@ that (a) aren’t manned by a real person or (b) don’t exist at all can be an easy way to alienate your customers and eliminate valuable feedback from your own users. If you send your email from a noreply address, here are a few reasons to make the switch to something new (like an email address manned by a real person):

  1. Your email is more likely to be ignored, flagged as Spam or deleted right away
  2. The message you’re sending to your subscribers (those current or potential customers) is that you’re not interested in hearing from them, even though it’s ok for you to email them. Is that really the message you want to send?
  3. You’re missing great (and sometimes crucial) customer feedback – user comments, unsubscribes – that can help you improve your marketing efforts (and see more return on investment)
  4. More often than not, when someone replies to your emails this interaction will automatically add you to their Contact or “Safe Sender” list at the same time which means all your future emails you send them will go straight to their inbox. Replies should be encouraged!
  5. Modern webmail & mobile email clients show people more than the name of the sender – they show your email address as well. Would you rather open an email from or from
  6. Using a noreply@ address has been shown to decrease open rates, increase unsubscribe and complaint rates

Not convinced? Check out what the pros have to say about it:

The CAN-SPAM Act: A Compliance Guide for Business “Your “From,” “To,” “Reply-To,” and routing information – including the originating domain name and email address – must be accurate and identify the person or business who initiated the message.” 
MAAWG Sender Best Communications Practices: “Senders should have the capability to process email-based unsubscribe requests. Senders should also consider making offline unsubscribe mechanisms available. The sender’s ‘From’ or ‘Reply-to’ email address should also be able to receive unsubscribe requests, unless otherwise indicated.” 

3. Transmit the Message Cleanly

Once you’ve written great content, designed a beautiful email, tested it and directed it at a targeted, segmented list, your work as the creator of the campaign is done. Now, it’s time to send your message!

The point at which you hit Send is really where a robust email marketing platform, like Cakemail, becomes absolutely essential. There are many obstacles your message needs to overcome between when you hit send and your recipient opens it. 

4. Sender Reputation

As a sender, you’ll gradually acquire a reputation as you send messages over time. The combination of your content, how often recipients flag it as junk, Spam traps, and your bounce rate all contribute to this reputation. A good reputation has a great impact on the effectiveness of your marketing efforts. A bad reputation does the exact opposite and may prevent it from reaching your audience at all. 

Cultivate and nurture your reputation by practicing good list hygiene, sending valuable content, and keeping your audience engaged. 

“A solid sender reputation is an important asset – without it reaching your audience can be a significant challenge that will inevitably impact the success of your marketing efforts.”

Most receiving networks use several factors to judge the reputation of a sender. Some of these are within the control of the marketer, and others need to be managed by your email service provider. They include: 

Managed By Marketers


This is the rate of formal complaints, or the number of recipients marking messages as Spam. Avoiding complaints relies on sending quality content to subscribers who have opted-in to receive your emails. For a more complete list of things you can do to avoid complaints, please refer to the “Assemble The Right List” section.

Hard Bounces

The hard bounce rate is the percentage of emails you send that are sent to expired or inactive addresses. This can be managed by maintaining an up-to-date subscriber list and ensuring it’s easy for people to unsubscribe or modify their information when their contact details or circumstances change. Most receivers monitor hard bounces very closely and will block your campaigns (even mid-send) if you have exceeded their threshold. Doing this regularly  will impact your deliverability.

Spam Trap Hits

This indicates how many of your messages are delivered to a Spam trap. Spam Traps are email addresses intentionally designed to identify spammers that are harvesting addresses off the Internet,  senders who have poor list hygiene, not removing bounces properly, or bad opt-in practices. To avoid this, make sure your opt-in process is a double opt-in list that requires people to confirm their email address before they are added to your list and send to these people on a regular basis so you can remove any invalid addresses that might eventually be turned into traps. 

Spam Score

This is the element of email deliverability over which marketers have the most control and yet it’s often the most neglected. What matters more than anything is bad content that encourages the recipient to ignore/delete your message, opt out of future messages, block you entirely, or worst of all complain to their ISP by flagging your message as Spam. 

Sender Compliance

This is measured by how well you adhere to the above requirements. Each mark against you will affect how your future email is handled. How each ISP deals with this can be different - some have higher thresholds than others so you are best to stay compliant in all areas in order to keep out of trouble.

Managed By Your Email Service Provider

Technical Compliance

In order for an email transmission to be successful it needs to follow certain technical guidelines, better known as RFC (Request for Comments), which is a set of standards for the internet as decided on by the IETF (Internet Engineering Task Force). At a high level, RFC compliance is solely the responsibility of your Email Service Provider and without it your email would not make it very far. 


Because spammers often masquerade as legitimate senders (claiming that their email is coming from a real company) receivers will often look to authentication as a way to see if the sender is really who they say they are. This is especially important when using an email service provider as they may (or may not) be allowed to send on your domain’s behalf. There are 3 main protocols in use today (SPF, DKIM and DMARC). For more information, please see our section on Authentication below

“Authentication helps validate your email as legitimate in an effort to maximize your delivery.”

A blacklist is a list used by receiving networks to judge a given IP and/or sending domain’s reputation. These lists are run by Anti-Spam organizations and most blacklistings are the result of sending Unsolicited Bulk Email (UBE) to addresses that never asked to receive it. There are many different blacklist providers in existence and some carry more weight in the community than others so it’s very important you keep your lists clean or you will run into trouble. 


While Whitelist and Accreditation services were once commonplace, they are not as popular today. In order to qualify, senders were required to meet certain criteria by generating  very few complaints, bounces and maintaining a high level of engagement with their users. If you are doing this now, chances are you don’t need to pay a 3 party service because your delivery is not a problem. 

4. Deal with Recipient Issues

The first step in fixing a problem is to find out what’s causing it. A good email marketing delivery platform is able to distinguish between different kinds of recipient issues, so the provider can easily determine whether it’s a transmission issue, list/content issue or due to poor sender reputation. 

“Many delivery issues can be resolved by quick intervention by the email marketing service provider on your behalf.”

In some cases, there’s nothing the service provider can do to remedy the situation – like when email addresses are invalid or when recipients choose to unsubscribe. This is one of the reasons that interactive marketing is more than just software: it sometimes takes human interaction to work through a delivery issue.

A number of obstacles can prevent or slow down your email in between. Here’s a look at some of them:

FBL Spam Complaints

Recipients who flag your mail as “Spam” or “Junk” have the greatest impact on your reputation as a sender. It is essential you avoid this by delivering great and relevant campaigns to recipients who want to receive it.

Users can (and will) complain about your message - to name a few:

  • if they have asked to be removed unsuccessfully
  • if your content isn’t of interest to them
  • if they don’t recognise you
  • if they don’t remember signing up in the 1st place
  • if you are emailing them without permission

This may be as simple as clicking the “Flag As Spam” button, or it may even involve reporting your email  to an authority that can take action.

“At the very least, messages being flagged as Spam will harm your reputation, but could also get you (or your domain) blacklisted.” 

A recipient marking your email as Spam will move all future messages to their junk or Spam folder, but it also tells their provider that messages of this sort—from this sender, about this subject, from this IP/domain—are more likely to be junk and unwanted which affects how future email sent to that provider is handled.

Always make it easier to unsubscribe than to complain

If your email is long, it is best to insert the unsubscribe link at the top of the email rather than all the way at the bottom (or include it in both locations).If somebody wants to be unsubscribed from your list, you are required by law to do it.

“The worst thing you can do is make it difficult for subscribers to figure out how to unsubscribe."

Soft & Hard Bounces

A “soft” bounce is a transient error—sometimes caused by the recipient's mailbox being too full but can also be caused by things like: Greylisting, timeouts, network congestion, domain/IP based throttling, and more… This  does not result in the removal of the recipient from the mailing list but may temporarily delay delivery to that person. Your delivery platform will retry delivery several times before changing the status of the recipient to invalid. 

A “hard” bounce is a permanent error resulting from an email address or domain that is determined to be unreachable after a single attempt. These addresses are considered to be “Invalid” and will be removed from your mailing list automatically. Email addresses and domains often change or expire – whether they are because of people changing jobs or domains expiring, occasionally recipient information may no longer be valid. Addresses may also be entered incorrectly when people subscribe for your mailing list if you use a single opt-in or manual/offline opt-in method. 

This issue can be minimized by validating email addresses through double-opt-in confirmations on sign-up, giving users the ability to edit their subscription information (and thereby update their email address if it changes), and by maintaining frequent communication with your subscribers to ensure the list is as up to date as possible. 

Transmission Rates & Errors

One of the things a good Email Service Provider manages for their clients is to control the rate at which your email is sent. It’s important to make sure you are not sending too much too fast as this can trigger blocks or otherwise raise an alert with ISPs that there is a sudden increase in traffic (this is especially true of IPs with little or no sending history). These flags can lead to timeouts, throttling and more resolute blocks, damaging your reputation in the process. 

Email Client Spam Filters

Even if your message has made it to your recipient’s mail server, a client-side Spam filter may still prevent it from reaching their inbox. While server filters block out egregious Spam, client-side filters are more personalized. Some email clients build their own profile of blocked senders and Spam words, and also can learn what the recipient considers to be Spam over time.

Messages Deleted By Recipients

Even if your email is something a recipient opted-in to receive, and the content is of interest to them, they may simply delete your message without taking any action – perhaps without ever opening the email at all. For the call-to-action in your message to be effective—telling a friend, buying a product, or accepting an offer, for example—the content has to be engaging and has to prompt the recipient to take the action you intended.

More than ever, ISPs are looking at engagement metrics in addition to complaints and bounces when determining your sender reputation, so the fewer recipients who delete your messages and the more they open or click the better.

Recipients Unsubscribe from Future Messages

At any point, recipients might decide they are no longer interested in receiving emails from you. Subscribers unsubscribing from the list will not necessarily harm your reputation as long as they opt-out through a valid unsubscribe link that is included in your email. Unsubscribing should be easy – requiring users to log in, retype their email address or other steps can lead to user frustration and complaints, this process should be as simple as possible.

To make it easy for your recipients to opt-out, consider including an “Instant Unsubscribe” link that requires only a single click in your message. You can do this automatically when you send your messages with Cakemail simply by clicking the “Add a standard Unsubscribe Link” checkbox when you’re creating a new campaign. 

“Continuing to contact someone after they’ve unsubscribed from your list is illegal and violates the Cakemail Terms of Use Policy.”

5. Track the results

Email marketing is an iterative process, as you gradually tune your audience and content to achieve the best results. To do this, you need to track every aspect of your campaign: whether messages are delivered, opened, clicked, forwarded or if they have been acted upon.

Tying email marketing initiatives to business outcomes is essential to their success. Doing so tells you what impact you’re having on lead generation, online sales, and other core aspects of your business. If you neglect this analysis, not only will you be unable to improve your marketing effectiveness, you will be missing out on important feedback that can impact your reputation and it will be difficult to show the rest of your organization the results of your hard work.

6. Manage list hygiene

A good email marketing solution will make sure the list you are using is clean. They will remove nonexistent domains and invalid recipients and will quickly remove recipients who opt out from future emails or complain. 

Ensuring that your list is clean is up to you. Starting with a valid, properly qualified list of recipients and an email marketing platform helps to automate some of the ongoing list maintenance as you send emails and build a good sender reputation.

“Good list hygiene contributes to your overall reputation, and demonstrates that you’re acting in accordance with  legitimate email marketing practices—making your message more likely to reach those prospects and customers who want to receive it.”

7. Fine-Tune Content to Maximize Engagement

All of the tracking that you’ve done means nothing unless you use it to your advantage to optimize future content. What kind of messages cause an increase in unsubscribes? What offers encourage people to forward the message to their friends? Which prices or colors trigger purchases?

By evolving your marketing efforts using segmentation and campaign analytics, you can maximize the effectiveness of your campaigns. Some emails, even though they’re legitimate, simply never get opened. Bad subject lines are often the culprit; marketers need to craft compelling, action-oriented subject lines that convince the recipient to open them. They should always entice the recipient to open &  click. 

Online marketing has changed over the years. Companies today need to interact with and engage their audiences now more than ever. An engaged user visits your site frequently, clicks on links in emails and interacts with a company’s brand on Social Networks. ISPs and email providers are adapting to this, using the level of recipient engagement as a measure of a sender’s reputation.


Gone are the days when you would send an email and not have to worry about it getting delivered. SPAM has been around for almost as long as email and receivers today have quite a job deciding what is real and what’s not. Wouldn’t it be great if legitimate senders had a clever way of helping them accomplish this? If there was only something we could do to help our email hit the Inbox and separate us from the junk. Well, keep reading because that’s exactly what Email Authentication is all about.

If you look into the number of emails sent worldwide every day, the results are quite staggering. According to Statista, there were approximately 306.4 billion emails sent in 2020 (every day), and this figure is expected to grow upwards of 347.3 billion per day by 2023. Even more shocking is the fact that over 50% of that is SPAM! 

“Spam messages accounted for 45.1 percent of email traffic in March 2021. During the most recently measured period, Russia generated the largest share of unsolicited spam emails with 23.52 percent of global spam volume. Despite its ubiquity, the global e-mail spam rate has actually been decreasing: the global annual spam email rate in 2018 was 55 percent, down from 69 percent in 2012.” (source: Statista)

How is this possible? 

Have you ever received an email from “Microsoft'' claiming your computer is infected, or your account password is about to expire?  How about an email from PayPal saying they are about to close your account unless you Login now!  Sadly, scammers have gotten very good at impersonating these organizations. Many people fall victim to these scam emails every day and lose $100 millions of dollars every year. 

Because spammers often masquerade as legitimate senders (claiming that their email is coming from a real company) receivers will often look to Authentication as a way to see if the sender is really who they say they are. 

What do I need to authenticate my domain?

Are your emails landing in spam? Keeping your brand consistent will directly affect your deliverability. In this regard, you will need to authenticate your domain and brand your links. Being recognizable and having a strong brand presence is crucial in today's world. 

How will this benefit me?

Authenticating your email will not only increase delivery, but make it more secure in transit, and reduce the chance of email you send getting flagged as spam. It will separate your legitimate email from a spammer trying to use your domain without your permission. 

What will happen if I don’t authenticate my domain?

You run the risk of someone else affecting the reputation of your brand. You will also run the risk of emails being flagged as Spam and sent to the Junk box. If you are using an ESP, chances are your email is being authenticated and you don’t even know it, but ESPs will use a shared domain to accomplish this which will not only not match your own, but could be affecting your deliverability. 

What is Authentication?

At its core, Authentication prevents spammers from using your domain to send email without your permission. There are 3 main protocols in use today (SPF, DKIM and DMARC) and authentication helps validate your email is legitimate in an effort to help maximize your delivery. This is especially important when using an ESP (like Cakemail), as they may, or may not be allowed to send on your domain’s behalf.

For more information on the different types of Authentication with Cakemail, please visit Authenticating my domain with SPF, DKIM and DMARC protocols

CASL and CAN-SPAM Compliance

It is very important to follow Anti-Spam laws that apply to the region you are sending email to (or from). The Canadian Anti-Spam Legislation (CASL) and the CAN-SPAM Act in the USA  were introduced to establish the minimum legal regulatory standards to which marketers must adhere to to remain compliant. Both CASL and CAN-SPAM apply in a variety of situations: 

  1. If you are sending email to subscribers based in Canada or the United States
  2. If you are sending email to a domain that is hosted in Canada or the United States 

However, compliance alone will not guarantee delivery. What is important to point out is that it only takes one address in a contact list to require you to adhere to these laws. So as a general rule we recommend everyone  adhere to the strictest rules of the road to ensure global compliance.  

There are two basic kinds of email you might send:


Advertises, promotes or encourages the recipient to participate in a commercial activity, including content on a website operated for a commercial purpose.

Transactional or Relationship 

Facilitates an already agreed-upon transaction or updates a customer about an ongoing transaction.

“If the primary purpose of the message is commercial, it must comply with the requirements set forth by the CASL, CAN-SPAM and other Anti-Spam legislation.”

If your message is transactional in nature, its primary purpose is transactional and must not contain false or misleading header information, but is otherwise exempt from most provisions of these laws. That stated it is best practice to not use a deceptive subject line, make sure you tell recipients where you are located and provide recipients with the ability to opt-out from receipt of further messages.

What does this mean? 

You’re allowed to include commercial-based content in transactional emails as long as the transaction remains the email’s “primary purpose”, with the subject line and message body emphasizing the transaction. This gives you an excellent opportunity to make a good first impression with your customers, but it is a delicate balancing act. If this is not done properly, you risk some hefty fines, generating complaints and affecting your delivery.

Find more information on CASL and CAN-SPAM as well as other countries laws in the Laws and Regulation section of our blog.

Image of the whole process and everyone's reponsibilities
This graphic outlines what parts of the process are the responsibility of clients & their agencies, which are the responsibility of an Email Service Provider, and what delivery obstacles might get in the way (or need to be overcome) while your email is on it’s way to your recipient’s inbox.


Messaging Anti-Abuse Working Group (M3AAWG): Sender Best Communications Practices, Version 3.0

Coalition Against Unsolicited Commercial Email (CAUCE)

ESPC : Email Service Provider Coalition


Authentication and Online Trust Alliance (AOTA)

Email Experience Council (ECC) - Part of the Direct Marketing Association (DMA)

Spamhaus - Understanding DNSBL Filtering

Share this

Text Link
This is some text inside of a div block.

Lorem ipsum dolor sit amet, consectetur adipiscing elit. Suspendisse varius enim in eros elementum tristique. Duis cursus, mi quis viverra ornare, eros dolor interdum nulla, ut commodo diam libero vitae erat. Aenean faucibus nibh et justo cursus id rutrum lorem imperdiet. Nunc ut sem vitae risus tristique posuere.