Knowledge Base > How It Works

Glossary of Terms

Accepts All

A mail server that will accept mail from any host that attempts to send mail to it. 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! This term is also knows as catch-all.

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 received this message.

Account Suspended (MailChimp)

If your account has been "Flagged for Review", then MailChimp'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 the one-time tuneup to clean your email list, we'll provide you with an Address-by-Address analysis of the emails within your list. We analyze your list to determine each email's verification grade and codes.


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 their 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 verification checks.


A comma-separated value (CSV) file stores tabular data (numbers and text) in plain-text form and is widely used by consumers and businesses. 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 verified, you'll have the option of downloading a 'Safe List' or an 'Everything' List'. Both of these lists will be available for download in a .CSV format within a .zip file.


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.

Email Assurance Grade

Your Email Assurance Grade is provided on your Free Report, and is based on the deliverability of emails within your list.

Free Report

DataValidation's Free 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.

Email Verification

Email Verification, aka One-time Tuneup, is a one-time email verification, or cleaning service, providing you with an Address-by-Address analysis determining the deliverability of emails in your list. With the One-time Tuneup, you can download the "Safe" list (containing only A+ and A results) or the "Everything" list (containing all the emails in your list, regardless of deliverability).

Everything List

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

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 affect your sender reputation.

Merge Fields

Merge fields are the fields within your MailChimp account that hold additional subscriber information such as phone number, address, etc. 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 therefore revoking permission to email them.


Having permission means having a person's consent to send them emails. By opting-in to your email list, a subscriber has given you permission to send them emails. 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 correspondence, 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 List

When an email has been listed as "Safe" by DataValidation's bulk email checker, you can rest assured that this email is deliverable. After having a list verified, you'll have the option of downloading a "Safe" or "Everything" list. Emails on your "Safe" list have a verification 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 Verification, we recommend sending only to the "Safe" 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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