Validation is one of the most important tools an email marketer can use. With it, you get a better understanding of which addresses on your email lists are truly valid and which are potentially damaging your reputation just by receiving (or rejecting) your email. To maximize deliverability and ensure your message is getting in front of the right audience, validation is an essential tool. However, there are many misconceptions surrounding it, which can harm your marketing efforts.


What is Validation?

List validation is a way to help you better understand if recipients on mailing lists still use their provided email address. It even works if you haven’t sent an email to their address for a long period of time. For example, you may need to share privacy policy updates to your lists, thanks to regulations like GDPR, even though you may have stopped actively sending to a disengaged segment. By validating your list before sending, you decrease your chances of emailing bad addresses that will negatively ding your reputation, and later, your deliverability as a whole.

There are two primary methods of email verification: instant and bulk upload. In order to optimize deliverability outcomes, marketers should regularly employ both methods when checking lists.

  • Instant: Verification takes place immediately upon receipt of an email address. It serves as a preliminary check as the address is added to a list, authenticating active addresses and flagging questionable ones.
  • Bulk upload: Email addresses are validated en masse on a routine basis. These checks serve as an effective ongoing audit to ensure no addresses slipped through the cracks during instant verification, or, in the absence of instant feedback, at least one quality control method. Ideally, bulk upload validation is performed daily.


Once you’ve validated your list, you receive feedback on each address via various subclassifications. A few are self-explanatory, but to a non-technical marketer, they may be hard to distinguish between. With a go-to glossary of validation terms, you can make much better decisions on whether or not to contact an address.

  • Valid: The address is capable of receiving mail. It doesn’t completely guarantee an engaged recipient but verifies it will receive your message.
  • Undeliverable/Invalid: The specific address can’t be reached or isn’t set up to receive emails.
  • Accept-All: The address accepts all messages. Some companies like Verizon Media Group use this as a tactic to detect when marketers are reaching out to non-consenting addresses.
  • Disposable: The user submitted a temporary address which will expire after a certain amount of time.
  • Role: The address isn’t one specific user; rather, the address forwards messages to multiple people such as
  • Typo: The email address was likely entered incorrectly.
  • Risky: The address may have been compromised by a data breach or may be used for questionable purposes. It may have frequent complaints or issues with spam traps or sensor networks.
  • Unknown: Validation services are either blocked outright from receiving key information or an intermittent connection issue prevented validation from taking place.


These classifications are useful in identifying how to best proceed with an address. Be sure to note, simply validating an email address does not provide consent to email. While certain list validation vendors will agree to clean a purchased list, many services (like 250ok’s tool) will not engage with purchased lists, because no matter how many addresses return valid, none of them have consented to be emailed, which is the definition of spam.

Validation also does not equal verification. The two are often interchanged, but to properly manage addresses, the two need to be considered separately. Verification is achieved through a specific action originating from the user of the email address, often within the context of a received message. For example, verification can be achieved by clicking a subscription activation link. Validation does not offer this level of active verification. Both are necessary to ensure addresses are safe, active, and willing to receive your messages.


Myths About Validation

There are many myths and misconceptions surrounding validation and email marketing. Even with a clear understanding of what validation does, you may be tempted to think it fixes all common issues with email marketing. Below are a few common myths surrounding validation and how to avoid falling for them.


Myth: Validation removes all spam traps on your list

A few services advertise such an ability; however, your database won’t truly be protected from all spam traps. ISPs and anti-spam agencies never disclose which email addresses are traps, making it impossible to remove every single one. If you use a solution offering to filter spam traps, ask where they obtain their traps and how you will be protected should you still encounter traps while using their service.


Myth: Validation fixes list-bombing issues

List bombing is the practice of flooding email sign-up pages with many new email addresses at once. A validation tool cannot distinguish between a real email involved in a list bomb and a real email submitted by the actual user.


Myth: All list validation tools are the same (so you should go with the cheapest option)

While there are two primary validation methods for the marketer, such services may validate lists very differently from their competitors. Cost is an important consideration, but be mindful of the methodology and thoroughness of any service, whether it’s the most or least expensive. Also consider how its API integrates with your ESP. A slightly more expensive option may save you countless integration and security headaches.


Myth: Validation perfects your list

Even the best tools on the market aren’t 100% foolproof. When you boil down a validation test to its most basic elements, it measures the probability of an email address being valid and safe for your lists. Hard bounces are unavoidable, but the best tools significantly reduce their frequency and impact.


Myth: Validation fixes all deliverability issues

Data quality is key. If your list collection methods are poor, low engagement rates and high complaints can’t be fixed with validation. Only through proper opt-in methods, better targeting strategies and an improved email cadence will deliverability improve.

Myth: Validation corrects email misspellings

Typos can’t be fixed with validation. While an email address such as “” may appear to be a typo for a user named “Jon Smith,” there is a chance the user’s name is “Jo M. Smith.” Rather than removing an address like this, consider using double opt-in methods so Jo can get the content he or she requested.

Myth: “Invalid” email addresses are the only addresses you should avoid

Most validation services summarize your list by organizing it into classifications similar to the above. Valid addresses are generally safe and invalid addresses should be removed. However, as you can see, inherent risks remain with each of the other classifications. At the end of the day, only you as the marketer can decide what to do with your list. Validation simply helps you make a more informed decision.

Validation is a useful, game-changing tool for marketers, but it is surrounded by confusion and misconceptions. By understanding what it is as well as what it can and can’t do for your lists, you can use validation alongside good deliverability best practices to make email marketing campaigns as successful as possible.