Deliverability, Delivery & Best Practices

The only way to ensure good email delivery rates is to follow good sending practices and authenticating your emails.


You can authenticate your emails with DKIM and SPF, this tells your email recipient's mail server that FunnelBud is properly authorized to send emails from your email domain. All FunnelBud accounts are required to have this set up before you may send emails, so if you're reading this it is either already set up or in your project plan.

Good Sending Practices

Here are the guidelines you need to follow to have the best chance of reaching your recipient's inboxes:

  • Make sure that your contacts have all opted in to receive communication. Sending to purchased email lists is not only prohibited by FunnelBud, it can also potentially mean that one of your emails reaches a spam trap which will severely damage your domain's sending reputation.

  • Use FunnelBud's Engagement Tools - these help prevent you from sending to contacts that don't engage with your content, and are automatically turned on. Ultimately the number of delivered emails will increase, even though you are sending less emails. FunnelBud has proven the effectivity of this strategy and written about it in this blog article.

  • Keep sending emails regularly. If you have followed the practices above this can only improve your Sender Reputation over time as ISP's learn that your recipients are interested in receiving your content based on open and click rates among other metrics (each provider has somewhat unique metrics to measure engagement).

  • Ensure that your contacts all come from a legitimate opt-in source:

    • Filling out a form on your website

    • Events

    • Point of Sale

    • Any other type of opt-in where the recipient confirms that they would like to receive your content

Good sending practices essentially come down to sending to valid opt-ins and sending emails that people open and click, and avoiding too many sends to invalid email addresses and NEVER send to purchased lists. FunnelBud also prevents you from sending to unengaged contacts (people who don't open or click several mails) which ultimately results in more people receiving mails in their inbox. Invalid email addresses are also automatically unsubscribed. Larger providers will build a reputation of your sending practices over time and good practices will improve that reputation over time.

Internet Service Providers

While Internet service providers (ISPs) still encourage senders to avoid spam complaints, increasing weight has been placed on measures of engagement as a means of determining a sender’s quality. This change reflects a shift in the behavior of email recipients towards flagging emails as junk rather than formally complaining or reporting an email as spam.

ISPs control the last mile of email delivery, and ultimately make decisions about what emails get delivered to the inbox of their users. While marketing automation or email service providers can set you up for success in avoiding the spam box, the ultimate inboxing decision rests with ISPs and their particular inboxing algorithms.

Spam and undesirable commercial email has become a large enough issue that ISPs have been implementing changes to proactively route unwanted email into junk or spam folders, and in some cases block the email entirely.

These changes by ISPs improve the overall email experience by allowing only content a recipient wants to reach the inbox. The shift in monitoring recipient engagement on a sender domain basis helps ensure poor-quality senders are personally held accountable, and it protects inboxes at large from receiving undesirable content.

Here are some factors that ISP's may use to measure how well you follow good sending practices (Both the Domain and IP reputation are measured through similar metrics, dependent on the ISP's specific rules):

  1. Engagement: How many people open and click your emails

  2. Recipient Actions:

    1. Adding your From email to a Safe-Sender list may improve your domain reputation

    2. Marking your emails as Spam may damage your domain reputation in general, and future emails to the same recipient will almost certainly land in their Spam folder or be blocked altogether.

    3. Moving your email to Gmail's Social, Promotions or Updates folder, will mean that other people are more likely to receive the email in the same folder.

    4. Content Association - There could be nothing wrong with your email, but your message could look similar to a completely unrelated message that the recipient has marked as spam in the past.

  3. The number of Spam Complaints - a certain small number of spam complaints is acceptable, but if it gets too high your reputation will be damaged

  4. URL Block Lists: There are several public block lists that contain URL's and domains that have been labelled as malicious. ISP's may maintain their own lists as well.

  5. Spammy Content: Normally nothing to worry about if you send legitimate content. Certain providers may look negatively on:

    1. ALL CAPS subject lines

    2. Pure promotional sales content (good inbound marketing always hides sales content as educational materials etc.)

    3. Offensive content or hate speech

    4. If your message looks similar to a completely unrelated message that the recipient has marked as spam in the past

  6. IP and Domain Sending Reputation: The history of sending measured by the factors above will affect the IP reputation, which in turn affects future delivery.

If the email passes the ISP's filters, it can still be marked as Spam by your own email client or email server's rules. If your server blocked the email, it likely won't be in your Spam folder. If your Email Client blocked the email, it should be in your Spam folder.

Sender Reputation

ISPs track the reputation of individual sender domains. This means your domain reputation is more important than ever and is your responsibility to maintain. Switching email providers or marketing automation platforms will not remove damage inflicted on your domain reputation due to poor sending. That damage will follow you regardless of which provider you choose.

While the importance of sender domain reputation has increased, the IP pools used through your provider will still have an impact on the deliverability of your content. FunnelBud uses SendGrid, the industry leader in cloud-based email service, to provide customers with the highest-quality sender IP pools. Together, they get the emails to the ISP for each recipient.

The ISPs then use the historical recipient engagement and content analysis to make the final inbox decision. Delivering highly engaging content to recipients who want to receive it will increase your overall email engagement and keep your domain reputation in good shape with ISPs.

All factors that influence delivery, summarized

  1. Authentication | Authentication involves setting up DKIM and SPF, which is required to send any emails from FunnelBud.

  2. The Sender IP Reputation | The IP address belongs to the sender (the system currently uses SendGrid, and has a very large pool of IP addresses), all sending IP's have a reputation similar to your domain reputation. Certain institutions montor sending IP reputations based on behavior, sending to Spam Traps and other bad practices can damage the sending IP. Sending IPs are managed automatically, and any damaged IP addresses are removed from the sending pool within hours.

  3. Your Domain Reputation | This is linked to your own email domain, and will apply regardless of which platform you send emails from. Most large email providers will have their own rating of your domain's reputation based on your sending history. The only way to maintain or improve your domain's reputation is to continue sending emails and follow best practices - a damaged reputation can be improved over time if providers detect that you are following better sending practices, and each provider will use slightly different metrics to measure how closely you follow good practices.

  4. Email Content | In most cases, this is nothing to worry about. Some providers will block emails with certain keywords, you should be fine as long as you send reasonable content that does not contain any hate speech FunnelBud notification emails tend to be blocked by your own mail server after some time, because all of these emails look very similar and can be sent rather frequently, a hallmark of spam. For Notifications, it is best to white-list FunnelBud's sender to ensure that these critical notifications are received. Overall, the best recommendation is to ensure you only email recent, and directly opted in contacts with content relevant to what they signed up for and at a frequency they are expecting. Anything outside of this framework could be deemed unsolicited.

  5. ISP Specific rules | More details in the Internet Service Providers section above

For additional information read our blog on Email Best Practices to Improve Email Deliverability

Written by: Sam Koekemoer