Ask the Expert: Jennifer Lantz, VP of Industry Relations, Kickbox

December 13, 2022
Written by
Denis O'Sullivan
Opinions expressed by Twilio contributors are their own
Reviewed by
Ayanna Julien
Opinions expressed by Twilio contributors are their own
Alex Price
Opinions expressed by Twilio contributors are their own

Ask the Expert: Jennifer Lantz, VP of Industry Relations, Kickbox

Countless myths abound in the world of email deliverability. That’s why there’s no one better to clear up these common misconceptions than the leading experts in the world of email. Every month, we’ll bring you a Q&A with leaders from inbox providers, spam trap networks, antispam systems, and more in our new Expert Series blog. 

In our fourth Expert Series blog, we chat with Jennifer Lantz. Jennifer is a self-proclaimed email geek and Excel fan. She’s a champion of industry best practices to fight abuse and help good senders navigate the often choppy waters of email delivery. Jennifer previously led the deliverability team at Zeta, managing client setups, authentication, troubleshooting, and ongoing strategy. She’s now heading up industry relations and providing deliverability consulting at Kickbox.

Now, let’s dive in.

14 questions with email best practices champion Jennifer Lantz

1. As a VP of Industry Relations at Kickbox, what does your role entail? 

Lots of fun stuff! I lead our consulting services, so I get to work with clients to review their programs, identify issues, and help them to resolve the issues. Also, I regularly contribute to our Kickbox blog. There, I get to write about my favorite topics, which is mostly deliverability, and things I’ve learned and continue to learn as the industry evolves.

I also attend conferences to present/educate on deliverability and participate in working groups, such as Messaging, Malware, and Mobile Anti-Abuse Working Group or M3AAWG, to review the current abuse landscape and how the industry can work to combat it.

2. How does email validation work? 

Email validation is a great practice to help marketers maintain a healthy email database (opt-in emails only, please). It works by reviewing the quality and validity of each email address, including those currently on your list, just joining your email list, or haven’t engaged with your brand for a while.

Regularly verifying your email data can help marketers identify bad and low-quality emails that, over time or in high volumes, can start to impact deliverability.

3. How can email validation help improve your sender reputation?

A high bounce rate can influence a sender's reputation, especially if this is persistent and combined with negative engagement metrics, inactive emails, and poor-quality domains. 

However, what’s becoming a larger issue is that not all email service providers process bounces the same way or use the same bounce thresholds. This means having a good understanding of your list and each address' risk level can help senders decide which emails they want to keep sending mail to and which emails they want to pull.

4. Can you explain what an accept-all domain is? 

Great question. An accept-all domain accepts a message regardless of if the receiving address exists. This helps to deter bad actors from running dictionary attacks or scraping data or other information in hopes of identifying legitimate addresses that they may later sell to other parties.

5. Is there an ideal hard bounce rate that senders should aim to stay under?

The line defining good and bad bounce rates varies by industry and stream. Take, for example, a welcome series, which trends higher with bounces, especially if the welcome incentive is an offer that doesn’t drive loyalty. By monitoring your bounce rate over time, you find the variances in a stream and overall program. 

That said, when reviewing bounce rates for clients, I would dig into those with a total bounce rate higher than 3% (overall for the program) to see what was driving it and if it was due to soft bounces or hard bounces. If hard bounces near 5% and above, there’s definitely a list-source issue, form compromise, or targeting concern.

6. Are there any financial benefits to running email validation during point of collection/sign-up?

The biggest financial benefits come in 2 forms: retaining interested customers and a high-quality list. 

The point of collection is a time when interest is high, and one could argue that's when validation is most necessary. And since marketers spend so much effort acquiring leads, to lose potential customers due to a simple typo would be a shame. Real-time validation helps you keep the prospects you connect with in your marketing funnel—a tremendous benefit to your bottom line.

So when someone accidentally enters an invalid email address, you have the opportunity to prompt them to enter a correct email address. Otherwise, you could lose a highly interested customer.


Plus, it won't cost you to send to invalid or low-quality emails. And your sending reputation won't take hits due to email collection issues either.

7. Can you explain the different types of validation and what benefits they each offer, e.g., real time versus bulk? 

Real-time checks on the validity of an email address occur at the point of collection, say through an online capture form. It’s a great way to keep your database from collecting a list of low-quality lists. And it’s a great start to protecting your forms.

Bulk (or email list verification), on the other hand, is typically when a sender looks at their historical list and wants to check on the status of the addresses they haven’t sent mail to in a while.

Knowing lists can churn around 30% a year, list verification is a great way to weed out churned addresses, so planning to mail to them (through a well-strategized path, of course) will keep the bounce rate at a minimum.

8. When an email address goes through validation, it’ll return a result of deliverable, undeliverable, risky, or unknown. Can you describe each and what action you recommend based on the result? 

Sure thing. And you can find these in our Kickbox docs as well.
  • Deliverable: This means Kickbox was able to identify the email address, mail to it successfully, and apply an additional layer of analysis to determine if we consider it safe to send email.
  • Undeliverable: This means Kickbox found these emails don’t exist, or we identified them as having syntactical issues, like 2 @ signs. If you send to these addresses anyway, they’ll hard bounce.
  • Risky: This means Kickbox found these email addresses to be potentially problematic, which may or may not result in a bounce or cause deliverability issues. We recommend sending with caution or setting them aside for further testing to see how these impact your email program. These include, but are not limited to, disposable emails (which may not bounce at first but will bounce once they expire), role accounts, and accept-all email addresses (which we just touched on.)
  • Unknown: This means Kickbox was unable to provide a result for an email address, so we added an unknown flag to it. However, this doesn’t mean this address won’t be available later, but when we checked it, there could have been issues around the DNS, receiving server issues, etc. Kickbox doesn’t charge or take credits away for addresses that come back as unknown.
In addition to these results, we also add in a Sendex Score to help you weigh the quality of addresses—even those that are deliverable. This is an easy way to create a risk threshold around which emails you want to keep.

9. Kickbox also offers a Sendex Score for each email address? Can you describe how that scoring system works?

Oh, I jumped ahead a bit on this. It’s an algorithm that considers the knowledge we have about an email or domain and generates a risk value based on all the inputs and information we have. Anything above .7 for marketing mail is good.

10. In a post-Apple Mail Privacy Protection world where senders have less access to engagement data, does it impact how senders should treat older email addresses in their database?

First, senders don’t have less access to engagement data but rather less accurate data. So does this impact how one would treat older addresses? Yes and no. Older doesn’t necessarily mean bad or low quality. It’s about what we know about them, including history.

Moving forward, if a sender tries to value an older population they were sitting on and just recently sent mail, it’s harder to tell if the responses indicate true engagement or if the activity is mechanically driven—e.g., a machine open due to Apple Mail Privacy Protection. Instead, focus on the hard data points you have at your disposal as an affirmation of activity—e.g., clicks (although still skewed), site visit or purchase, etc. 

Then, for those that may seem to be engaged but don’t have a more affirmative action beyond opens, approach them cautiously. You can start to strategize how to reach out to them to drive an action that gives more data on their current relationship status.

Lastly, for older addresses that lack any activity, especially if your other data points (website, etc.) mimic that lack of activity, you have enough data to identify them as low value. At that point, determine which ones you want to re-engage, re-permission, and cut loose. Use the age and last activity date to determine this.

11. You can use data verification/validation in numerous ways to improve your email marketing program. What are some ways that people shouldn’t use it, or what shouldn’t people expect it to accomplish? 

I would call out the 2 most significant use cases that come to me. First, a Spamhaus listing occurs, and I get asked if verification is the solution. The answer is no.

Kickbox, at least, doesn’t identify spam traps. So all verification does is confirm if you’ll get a bounce or not when you attempt to send the email. When it does, it pulls out low-quality emails that can harm your reputation by diluting the good email sent out of your system. However, it won’t remove the Spamhaus traps you hit.

And tied to this, Spamhaus listings and deliverability issues resulting from a lack of engagement or negative engagement related to consent/expectations. As a result, Kickbox cannot and does not verify consent. And the reason is that traps are supposed to remain obscure and hard to find.

So if you’re mailing them, reviewing your list source, targeting, and consenting practices, that’s how you’ll be able to right the ship—and that is what you need to do first.

12. Does the implementation of real-time API validation have any security benefits, e.g., will it help protect or draw attention to scripting/bot attacks? 

Verification is a great first step and will help weed out the junk entered into your form by bots. But if a bot enters data that’s legitimate, Kickbox can’t confirm if it was true intent or a bot (by the address alone). Again, consent isn’t something verification confirms. 

However, we monitor our system for activity that may indicate abuse—through a poorly acquired list or activity that may indicate a compromise. Protecting our systems and our customers is core to our business and philosophy, so we continually explore additional ways that we can improve the security features tied to verification to help identify and report abusive activities. 

For now, the reporting that comes with verification is a great way to monitor activity. However, the most effective ways to protect your forms are to start with verification and add on practices like CAPTCHA, confirmed opt-in, and honeypot fields.

13. What’s a disposable email address and how should senders treat them? 

Oh, this is a good one. A disposable email address can occur in 2 ways. The first way is when there’s an email address that someone may toss at a later time. This can be in the form of legitimate, lasting domains like Gmail and Yahoo! using aliases or secondary accounts. These disposables are valuable because you have a person on the other side, but you don’t know how long you have them for (1 day to 10 years).

Secondly, there are disposables, as defined in our verification service, which are email addresses coming from services specializing in short-lived accounts. These typically expire in 24 to 48 hours and may not even belong to an individual user. Disposable emails, by this definition, don’t last long, waste your resources, and could end up exposing customer data if the provider puts all incoming emails in a shared inbox.

14. How does email validation help lessen your chances of sending to typo traps?

Kickbox doesn’t identify traps of any kind, but we do highlight low-quality emails or those mistyped into a form or point-of-sale system. In those instances, we offer a “did you mean” value to help guide you. 

By identifying the deliverable emails that may have quality issues with our Sendex Score, you can begin to identify the lower-quality emails to pull them from your database or at least flag them for further analysis once you engage them. In this way, you can reduce your chances of hitting typo traps.

However, some typos are legitimate domains, which is why Kickbox will never correct or adjust your data. The decision to mail, suppress, or update (which I personally never recommend) is a business decision that you have to make.

Thanks to Jen! And be sure to stay tuned each month, as we’ll chat with another expert in the world of email marketing to provide you with further insight into the ins and outs of email deliverability. 

Until next time, check out Twilio SendGrid’s Email Deliverability Services packages to get started, or contact our Sales team to learn more about improving your email deliverability.

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