Glossary of Terms

Accepts All

A mail server that will accept mail from any host that attempts to send it mail. This happens regularly for business email addresses, and even some personal ones too. These addresses are considered to be characteristic of a spam trap as well! 

Account Flagged for Review

An "Account Flagged for Review" message from DataValidation means that your list has been flagged by our automated abuse detection program for containing potentially harmful data. Please contact Customer Support if you've received this message. 

Account Suspended (MailChimp)

If your account has been "Flagged for Review", then MailChimps's review system (or human review team) noticed something about your last campaign, your account, or the lists within your account that raised a red flag for them. 

Account Under Review (MailChimp)

Sometimes, MailChimp sees things that need some explaining or investigating, and the review team takes a little time to check things out. This message could have something to do with a campaign you sent, your account, or the lists within your account. 

Address-by-Address Analysis: 

When you purchase Email Assurance or Email Validation, we'll provide you with an Address-by-Analysis of the emails within your list. This analysis contains Deliverability Codes and is what determines the overall deliverability of an email. We use this analysis in determining an email's Email Assurance Grade. 


When we say "blocked" we're referring to being blocked from sending email. You can be blocked from sending mail by your Email Service Provider (ESP) and if this happens, you'll need to get back in compliance with their monitoring standards. We're here to help you do that!


Staying in compliance with your Email Service Provider, or with industry best practices, means that you are following general rules and guidelines, or Terms of Service. Check with your ESP to determine what your compliance standards are as far as sending email. 

Confirmed Deliverable

If an email has been "confirmed deliverable" then the address is safe to send email to. This means that deliverability has been confirmed by our system's multiple validation checks. 


A comma-separated value (CSV) file stores tabular data (numbers and text) in plain-text form and is widely used by consumers and business. A .csv is one of the file formats we accept for users who want to upload email lists to our system. Once a list has been validated, you'll have the option of downloading a 'Safe to Send' List or an 'Everything' List'. Both of these lists will are available for download in a .CSV format. 

Deceased Individuals

Sometimes old email lists contain addresses belonging to people who have passed away. This email address may still be listed as active or could turn into a spam trap sometime in the future. This code indicates whether an email address belongs to a person who is deceased or not. Deceased Individuals are listed as D1 or D4 in your Address-by-Address Analysis. 


Email deliverability refers to the likelihood of an email reaching an inbox. The deliverability status of each address within your email list affects the overall deliverability of the list. 

Deliverability Codes

When you upload a list or link an account, every email within the list is validated and given specific Deliverability Codes that determine the overall deliverability of that email. These codes are what determine an address's Email Assurance Grade.

Email Assurance

Email Assurance is an ongoing monitoring service offered to clients with accounts linked directly to a MailChimp account. With Email Assurance, we monitor the lists within your MailChimp account, keep them up-to-date, and check for optimization and performance opportunities. 

Email Assurance Grade*

Your Email Assurance Grade is provided on your Free Email Assurance Report, and is based on the deliverability of emails within your list. Deliverability is determined by the Deliverability Codes provided in your Address-by-Address analysis. 

Email Assurance Report

DataValidation's Free Email Assurance Report is provided for every list within your linked MailChimp account (or for every list uploaded to our system). This report provides you with an Email Assurance Grade based on the deliverability of emails in your list. 

Email Service Provider (ESP)

A company offering email marketing or email services for a large number of people, allowing you to deploy campaigns to lists of subscribers. We currently partner with MailChimp to offer Email Assurance, a subscription service for Email Marketers who want to stay in compliance with ESP standards and best practices. 

Email Validation

Email Validation is a one-time cleaning service, providing you with an address-by-address analysis determining the deliverability of emails on your list. With Email Validation, you can download the "Safe to Send" list (containing only A+ and A results) or the "Everything" list (containing all emails on your list, regardless of deliverability). 

Engagement History

Now, with the new Email Assurance Grades and Deliverability Codes offered by DataValidation, you can see Engagement History for the email addresses on your list. We aggregate historical open and click information for addresses. This does not determine the likelihood of a subscriber opening or clicking your email.  

Everything List

Link a MailChimp account or upload a list and have the ability to download a 'Safe to Send' list or an 'Everything' list. The 'Everything' list contains all of your original email data and an Address-by-Address Analysis, with Deliverability Codes for each email in your list. Download this list for segmenting, or for your records, but do not deploy to the 'Everything' list.  

Hard Bounce

A hard bounce indicates a permanent reason an email cannot be delivered and can happen in the following cases: Recipient email address does not exist, an email server has completely blocked delivery, or the domain name at which you are attempting to send to does not exist. 

Historical Complainers (W)

Complainers are people who have a history of reporting email as spam. A historical complainer code will indicate whether a given email address on your list has a history of complaining about email or not. Historical Complainers are listed as a W1-W4 in your Address-by-Address Analysis. 

Historical Hard Bounces (H)

Historical Hard Bounce information is provided for each email address within your list specifying if an address has a history of bouncing. This information is gathered in terms of the specific address, and not how many times email has bounced from you. Historical Hard Bounces are listed as a H1-H4 in your Address-by-Address Analysis. 

Historical Opt-Out (O)

Historical Opt-Outs determine the number of people on your email list that have a history of opting-out, or unsubscribing, from email lists. A subscribers opt-out history is based on their overall email history and can help in determining the likelihood of opting-out from your emails as well. Historical Opt-Outs are listed as a O1-O4 and Historical Clicks are listed as K1-K4 in your Address-by-Address Analysis. 

Historical Engagement (R or K)

This is a measure of the historical level of engagement (opens and clicks) based on the amount of deliverable mail sent to an address. This is a historical reference, and does not determine how likely one is to open or click within your email. Historical Opens are listed as a R1-R4 and Historical Clicks are listed as K1-K4 in your Address-by-Address Analysis. 


When deliverability is listed as "indeterminate", it means that we have attempted checking an address with a mail server, but we are unable to connect. It cannot be determined whether the address is deliverable or not. 

IP Reputation

Your IP Reputation is a holistic view of your IP, taking into account factors including spam complaints, reports, email deliveries, and sender actions. Activity such as bounces, spam complaints, and low open/click rates can negatively effect your sender reputation. 

Merge Fields

Merge fields are the fields within your MailChimp account that hold additional subscriber information such as phone number, address, ect. When you link an account to DataValidation, we'll return all of the emails in your list with updated merge fields containing Deliverability Codes for each address. These codes determine the overall Deliverability Grade of the email. 

MX Lookup

An MX Lookup is a test we perform on that lists MX records for a domain in priority order. The MX lookup is done directly against the domain's authoritative name server, so changes to MX Records should show up instantly.


Omnivore is MailChimp's abuse-prevention initiative, gathering information from billions of emails to predict bad behavior. Omnivore gathers the necessary information it needs on email senders to keep them in compliance. 


Subscribers "opt-in" by filling out some sort of signup form for your email list. This is how you get a person's permission to email them. Best practices states that you should always use a "double opt-in" - having someone fill out your form first and then confirming subscription to your list. 

Opt-Out / Unsubscribe

When a subscriber "opts-out" from an email list they are unsubscribing, and therefor revoking permission to email them.


Having permission means having a person's consent to send them email. By opting-in to your email list, a subscriber has given you permission to send to them. According to email best practices, permission usually expires within months and needs to be re-confirmed. 

Re-Confirm Campaign

A re-confirm campaign is sent to subscribers on your list whose permission has been expired. This campaign reminds clients of your past correspondance, while asking them to confirm their email opt-in. 

Re-Engagement Campaign

A re-engagement campaign is designed for subscribers that have been "inactive" for a period of time. This campaign is centered around providing offers and promotions to re-engage subscribers on your email list. Usually, email marketers send a re-engagement campaign before a subscriber's permission is expired.  

Safe to Send List

When an email has been listed as "Safe to Send" by DataValidation, you can rest assured that this email is deliverable. After having a list validated, you'll have the option of downloading a "Safe to Send" or "Everything" list. Emails on your "Safe to Send" list have an Email Assurance Grade of A+ or A - Meaning they are deliverable, and in some cases have a History of Activity.  


List segmentation allows you to send to a target audience within your list, without having to send a newsletter to your entire list of subscribers. With Email Validation and Email Assurance, we recommend sending only to the "Safe to Send" category. Segment your list by emails with an Email Assurance Grade A+ and A to ensure deliverability.


An SMTP server is a computer that receives outgoing mail messages and routes them to their intended recipients. Messages often must pass through several servers to reach their destinations, and SMTP facilitates this. An SMTP Check verifies that the server has a reverse DNS (PTR) record. It will also measure the response times for the mail server.

Soft Bounce

Soft bounces typically indicate a temporary delivery issue for an email address. These bounces can occur because of reasons such as a subscriber's mailbox is full, a recipient email server is down or offline, or an email message is too large. MailChimp will attempt sending to soft bounces three times before they will be categorized as hard bounces.

Spam Trap

A spam trap is an email address that's not actively used, but is actively monitored. Spam traps can be set up to intentionally catch spammers, OR an email address that has been inactive for a long period of time may be used as a spam trap as well. 

Stale List

A stale list is one that has not been mailed to regularly. Usually with a stale list, the sender has failed to mail on a recurring basis OR the subscribers on the email list have become inactive and permission has expired. 


A subscriber is a person who has opted-in, or subscribed, to your email list. Your list(s) Email Assurance Grade is determined by the Deliverability Codes within your lists' address-by-address analysis. These Deliverability Codes provide valuable information on the subscribers within your list.


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