July 18, 2019

Email Validation 101: What is it and why should I care?


We’ve partnered with the inimitable Lauren Meyer, Mailjet’s global VP of delivery & head of operations, North America, to bring you a series of blogs about validation, one of the most misunderstood yet incredibly powerful tools in an email marketer’s toolbox. We’ll start with the basics.

What is List Validation?
In short, list validation can help you better understand if a recipient on your list is still using the same email address they’ve provided, especially if you haven’t sent them an email in a while. For example, if you are sending important account updates, such as a change to your Privacy Policy (something Mailjet knows all too well because of last year’s GDPR), then you will want to make sure the email you have on file will, in fact, reach your target audience. By first validating your list, you can ensure you will maximize deliverability, and get your message in front of the right people.

What a list validation cannot do, however, is create permission where actual consent from the recipient has not been given. I’m looking at you, marketing lead who just purchased a list for your sales team.

There are two primary methods of validating an email list; one being near real-time (“instant”) validation taking place upon collection of an address, or validation via bulk upload, which is typically performed daily in batches. In many instances with our customers, both instant validation (preliminary check at the point of collection) and bulk uploading (secondary sanity check after the fact) are in the mix. According to the Relevancy Group’s report, “The Power of Email Verification and Multi-Method Hygiene,” marketers using multiple validation methods outperform those that do not.

As a general rule of thumb, most list validation solutions will provide a number of results, primarily valid or undeliverable, followed by a handful of subclassifications to help inform the marketer on the composition of their list:

  • Valid: The address was validated, most commonly at the SMTP level, as an address capable of receiving mail. Note: this does not imply absolute validity.
  • Undeliverable (or “Invalid”): The address was determined to be invalid, due to varying reasons: SMTP error (such as a bounce code, or the receiver telling us specifically the address can’t be reached), invalid MX records (meaning the receiving address may not even be configured to accept emails), etc.
  • Accept-All: The receiving domain of the address accepts all inbound messages and does not return an SMTP response indicating validity or invalidity. While Verizon Media Group addresses (AOL, Yahoo, verizon.net) are known for this type of behavior, accept-all addresses are a common tactic by sensor networks to detect when marketers are emailing addresses they shouldn’t be emailing.
  • Disposable: The email address is a temporary, throw-away address that expires after some period of time.
  • Role: Role addresses are likely not a particular person, but rather a group, department, or distribution list that forwards on to multiple people.
  • Typo: The email address was likely typed incorrectly at the point of collection.
  • Risky: The email address is determined to be risky based on a number of factors. Some validation solutions point to frequent complaints, addresses listed on data breaches, or addresses associated with common sensor networks or spam traps.
  • Unknown: In some cases, an intermittent connection issue or unresponsive SMTP server prevented the validation of an email address. This could stem from an actual receiving mailbox outage, but we commonly see instances where validation services are blocked outright and are prevented from performing validation tasks.

Validation versus Verification
The concepts of list validation and email verification are commonly interchanged, but it’s important to distinguish between the two. Validation is simply a method for determining whether or not a message is deliverable to a specific address.

Verification, on the other hand, could be considered to be something different altogether. When we educate Mailjet customers about verification, we’re often talking about actions that verify an address, such as opt-in confirmation emails, subscription activation links, etc. What do these types of triggered messages have in common? They’re asking the recipient to verify their email address by performing a particular action. We look at email verification as an added benefit to validation; not only is the email address valid, but you also confirmed consent from the recipient.

Validation Myths
At Mailjet, we often work with brands who don’t quite fully understand what a list validation tool can and cannot do. To help you better understand what list validation can and cannot do, we’ve compiled seven common myths below, and how you can best overcome them.

Validation can remove all of the spam traps on your list

Hate to say it, but nope! Some list validation services advertise the removal of all spam traps from your email databases, however, it’s important to remember ISPs and anti-spam agencies never disclose which email addresses are traps. It is possible a list validation service can identify some of the traps out there, particularly typo traps, but you should closely consider the credibility of any company claiming to remove 100% of the traps generated by ISPs, Spamhaus, or other anti-spam agencies. If you are considering a service offering spam trap filters, be sure to ask questions such as where they obtain their spam traps and what kind of recourse you can expect if you still hit traps after using their service.

List cleanse can help solve a list-bombing issue

List bombing refers to the practice of abusing email list sign-up pages by inundating them with a large number of new email addresses at the same time. Unfortunately, as mentioned above, list validation tools are really only effective in helping identify inactive, invalid, and potentially risky addresses. People who have had their email addresses abused as part of a list bombing attack are still real recipients, and so a validation tool will not be able to distinguish between a real email and a real email involved in a list bomb.

All list validation services are the same, so go for the cheapest one

Like anything, quality varies greatly based on how each service validates their lists and how they provide their list. Everyone’s needs are different, so while cost can be one of your considerations, be sure to also consider the reputation, methodology behind their reporting, and how their API integrates with your ESP.

Your list is perfectly clean after a validation

Would you believe a house-cleaning service claiming they can make your apartment 100% clean? You’d be right to be a little skeptical of this promise. No service is 100% foolproof. List validation tools are essentially running a series of tests and checks to determine the probability that an email address is valid and safe to remain on your list. Most providers claim an accuracy rate of 98% or higher, however historically, results can vary greatly. It’s not uncommon to still see email marketers generating upwards of 5-10% hard bounce rates, even after doing a validation. The reality is, even with the best tools on the market, you should still expect to see some hard bounces.

All of your deliverability issues will be fixed after you validate your list

Data quality is of utmost importance for optimal deliverability. Validation services can help ensure your list contains less invalid addresses, but it cannot magically solve issues with high complaints or low engagement that come from poor list collection practices. List validation is one important tool in your toolbox, but it doesn’t replace other tools like ensuring explicit opt-in, targeting active users, and improving email cadence.

List validation services should correct misspelled email addresses

If you are trying to clean your list of typos or wrong domains, list validation is not your answer. If someone accidentally typed “johmsmith@gmail.com” instead of johnsmith@gmail.com, you may have the wrong email, but a list validation doesn’t know that for sure. Perhaps the email is for someone who goes by Jo HM Smith? ?This is why double opt-in is so important. It not only helps you get the right email but also helps your contact get the content they desire.

After a list cleanse, you should mail to all addresses not categorized as “invalid”

Most list validation services will provide a summary of your list, separating the addresses into different categories. Those addresses that are tagged as valid are typically safe to mail to, and invalid addresses should be removed.But, there are many other categories for the sender to deal with, based on the level of risk they are willing to accept. Imagine your fridge where you probably have food items that are fresh, items that are nearly expired, ones that are expired (but deep down you know are probably still ok), and of course the ones that are long-overdue to be thrown out. If you are having a BBQ, you still might serve the recently expired ketchup. But someone else might not!The categories you get after validation are similar, they present varying degrees of riskiness. It is up to the marketer to decide whether to suppress them all or roll the dice with some of the medium risks like role addresses (e.g., support@domain.com).

Next time, we’ll look at the pros and cons of using a validation service, because like all things, it’s not a perfect product and needs to be considered carefully. Until next time.

Author: Lauren Meyer

Lauren is responsible for Mailjet’s global deliverability and compliance, and also directs Mailjet’s North American operations. She is a data nerd at heart, who is passionate about spreadsheets and spends much of her free time juggling twins and searching for her next great slice of NYC pizza.

Author: Alex Griffis

Alex Griffis is the VP of Product (a product geek) at 250ok, where he focuses on product design and improving our customer experiences.

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