Email Deliverability - Improved

August 1, 2019 Claudia Kulaga

Based on the stats below, one of our clients’ overall email deliverability rate was very good (98.9% average). However sometimes certain email campaigns resulted in deliverability rates that were significantly lower than that average so we put together a list of tips and tricks for them to consider.

Client Stats:

  • 98.9% deliverability
  • .973% bounce rate
  • 7.9% open rate
  • 4.3% clicked to open rate
  • This client also has several deliverability best practices in place including:
    • An automated campaign in place in Marketo to manage bounced emails 
    • SPF/DKIM
    • SSO

Below are some tips and options to improve deliverability:

Dedicated IP

One option to boost deliverability would be to consider having a dedicated IP. This is generally only recommended for companies with high email send volume (at least 100,000 emails monthly). The things to take into consideration when thinking about a dedicated IP is that there is an additional cost for this. Additionally, it gives companies complete control over their sender reputation since that IP address would not be used by any other sender.

Data Quality

Another consideration are lists/data quality. Experiencing lower deliverability rates only inconsistently, is likely due to lists/data quality. Considerations to address this include:

  • Stop sending mail to purchased lists. Not only is this a violation of Marketo's Use Policy, but these sources are prone to include high rates of invalid addresses and spam trap addresses which may trigger blacklisting and blocks:
  • Review acquisition sources for quality. Look for indicators on forms where people fill out fake names or partners whose data is proving to be low quality.
  • Review your bounces for addresses/domains that are fake. 
  • Review your sending reputation to determine if your reputation is triggering blocks, blacklistings or spam folder delivery.
  • Review your sign-up forms and welcome streams. Ensure you are setting the proper expectations with your subscribers and keep them.
  • Perform a detailed quantitative analysis of your mailing program by looking for high rates associated with a data source, age and activity, response rates, customer segments, and content or campaigns. Make changes to your program/policies based on your findings.


If Spamtraps are a concern, to narrow the list of potential traps consider the following:

  • Have you recently added any new leads or new lead sources?
  • What is the source of these leads? Any purchased or appended email addresses should be removed because these data sources are often the source of newly introduced spamtraps. In addition lead sources like this can violate Marketo's Email Use and Anti-Spam Policy.
  • Have you recently added any older leads from another database that have not received email in the past year?  Some email providers will turn an address into a spamtrap after a year of inactivity.  
  • If you have a list of email addresses that have not received email in over a year or more, make sure to remove that list from your email campaigns.
  • Does your system use any custom fields to indicate customer status, event attendance, recent contact with your sales team, or other forms of engagement?  Take advantage of this and isolate the inactive or nonresponsive segments of your database using all activity data you have available.
  • Is there anything different about this specific mailing that makes it different compared to your previous email campaigns?
  • Did you send any other mail on the same day?  You could compare the recipient lists.


  • The best permission policy to mitigate complaints is one that requires affirmative consent, no pre-checked boxes or automatic enrollment with purchase. Of all permission approaches, Double Opt-in is the gold standard.
  • Implement a subscription center to allow subscribers to select granularly between mailstream options like newsletters and notifications versus promotions.
  • Ensure your frequency of mailing is appropriate. Allow subscribers to easily modify the type and frequency of messages they receive via an online preference center. Consider Summary/Digest options.

Email Design Considerations

  • Make it easier to unsubscribe than to complain by keeping your unsubscribe link in the standard places where subscribers look for them, in the footer or header.
  • Make sure you are using HTML best practices to keep emails from being blocked or filtered.

If you want to improve email deliverability, consider the tips listed above. Making a few simple changes to your existing processes can really go a long way toward maximizing the number of emails that actually make it to someone’s inbox.


About the Author

Claudia Kulaga

I have 9 years of B2B marketing experience with expertise in demand generation, lead generation, marketing automation strategy & execution, email marketing, and content development. Having worked both client side and agency side, I've worked for and with a variety of companies ranging from high growth start-ups and SMBs to multinational enterprises in industries that include technology, media, financial services, healthcare. I earned my MBA in International Business in 2007 graduating from Temple University's Global MBA program which has consistently been ranked as a top 20 program for International Management by US News and The Princeton Review/Entrepreneur Magazine. I became a Marketo Certified Expert in April 2013 and again in 2015. I am a tenacious, collaborative problem solver who approaches every task with curiosity, thoroughness, and a positive attitude while seeking the input of others and will give 120% every time.

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