Glossary of Terms

The glossary of terms contains definitions of the technical terms used by Verifigator.

Abandoned Inbox – Also sometimes called a dead inbox or dead email address means an email address that is valid but the inbox has been abandoned by its owner a long time ago. Do you remember that email address you once signed up for in 2002 but haven’t used in years? Yep, that’s what we call an “Abandoned Inbox.”

Blacklisting – Many anti-spam organizations maintain a list of known spammers, adding someone to these types of lists is called blacklisting. Blacklisting can happen to an individual email address, domain, or even an entire organization. If you get blacklisted, it can cause most or even all of your future emails to become flagged as spam and those emails will go directly to the user’s spam folder instead of the inbox. Sending email to spamtraps is the most common reason to get blacklisted.

Bounce – If you send email to a non-existing email address, you will typically receive an automatically generated reply from the destination email server informing you that the email address does not exist. This is called a “bounce”.

Bulk email address – An email address that exists in a so-called bulk email or mass mailing email lists that can be bought online. Email marketers and spammers sometimes buy a mailing list of millions or even billions of email addresses. Such mailing lists are very low quality and a legitimate business should never buy such mailing lists or send email to such mailing lists.

Verifigator owns a copy of most bulk email lists available for sale, if your email list contains many emails that also exist in these bulk mailing lists, it will lower the quality score of your list.

Disposable email Address – A disposable email address, or DEA, is a valid email address that has been created to be used only once or for a temporary use in general. Typically a user would create this type of email in cases when the user doesn’t want to give out their real email address. This type of email address is also known as a temporary email address or throw-away email address.

Email address domain part – The domain part is the part of email address that comes after the @ sign. In other words, the domain part of would be In a valid email address, the domain part must be a valid internet domain that is configured to accept incoming emails.

Email address local part – The local part of an email address is the part of email address that comes before the @ sign. For example, johnsmith1 would be the local part of the email address The local part must be at least one character long and cannot contain specific characters or character patterns.

Fake email address – A fake email address is one that has a valid syntax but is clearly a fake address. This would typically be something a user would type when he or she does not want to give his or her real email address.

For example, we would consider as a fake email address. It is, by definition, a valid email address in the sense that is a valid domain name and the email address has a valid syntax. The algorithm we use to detect fake emails is based on the way the human brain works: if you see an email address and you are thinking “this probably isn’t a real email address”, then our system should also flag it as fake.


Free email account – A free email account is, like the name suggests, one that a user can register for free. Services like Hotmail, Yahoo, and Gmail are the most popular free email account providers.

The distinction between a disposable email account and a free email account is that while both are free, disposable email address is usually created for a very short time use and usually without any registration or sign up to the service.

List-based (or on-demand) email address validation – When you already have a list of email addresses, for example, your existing newsletter subscribers, leads or customer database, you can run it through Verifigator to flag or filter out the invalid data, geo-locate your users based on their email addresses, guesstimate the languages they speak and guesstimate their gender. This helps to find a specific demographic and weed out the fake or disposable email addresses so that all emails sent out will be sent to real and active email accounts.

Real-time email address validation – In a real-time email address validation, a user’s email address is sent to Verifigator at the time of registration to your service or subscription to your newsletter. Typically within a second, Verifigator has analyzed the email address and returned the analysis result to your server so that you can determine if an email address is verifiable or not. Your website can then decide based on that information whether you should accept that particular email address or not. For example, if a user has entered an invalid email address, you can show the user an error message asking the user to enter a valid email address immediately upon entry.

Verifigator supports two operation modes, real-time and list-based.

Role based email address means an email address that is designed for a purpose, not for a person. The most typical role based email addresses are emails such as info@, sales@, webmaster@ and so forth.

SaaS – Software as a service. Verifigator is a SaaS-based product. This means Verifigator’s customers pay for the access to use the Verifigator service per month. Verifigator’s systems are constantly being updated for maximum accuracy and performance. An alternative to a SaaS would be the traditional software model where user pays a one-time fee to buy a license for a software, installs it to one’s own server and uses it from there. In the Saas model, the user doesn’t have to worry about server requirements, keeping the software updated, or be concerned about hardware or software requirements of the software. It also makes it accessible from multiple computers.

Spamming – Spamming means sending unsolicited emails to persons with whom one does not have a business relationship or who have not specifically requested (opted-in) to receive such emails.

Verifigator is not a service for spammers. We do not wish to have anything to do with businesses that are considered as spammers or who we consider as spammers. We do not help spammers to avoid spam filters and better deliver their emails. We help legit businesses to avoid being incorrectly flagged as spammers.

Spamtrap – Spamtraps are honeypot like valid email inboxes that have been specially created by anti-spam organizations to try to catch spammers. These email inboxes are monitored by automated software and if you send any emails to a spamtrap address, it can result your email and your entire website being blacklisted as spammer.

A spamtrap is used to expose illicit senders who add email addresses to their mail lists without user’s permission, such as malicious businesses who harvest the internet to collect email addresses or who buy bulk email mailing lists. Verifigator condones all such business practices. However, there are reasons why a legitimate mailing list could have spamtrap email addresses and Verifigator can flag and remove them for you

Valid or invalid email syntax – An email address syntax means what characters and patterns are allowed in an email address. For example, there must always be the @ character in an email address to separate the domain part and the local part.

What an email address should look like is defined in numerous Internet standard RFC documents, such as RFC 822, RFC 2822 and RFC 5321.

It is important to remember that a valid syntax doesn’t mean that the email address is valid. For example, has a valid syntax but it’s not a valid email address if the domain part is not actually a real domain.

API calls remaining – This is the total number of API calls available in the account at the moment. Analyzing one email address or one lead will consume one API call. For example, if you want to verify 100 emails, it will consume 100 API calls. Or, if you wish to add 200 leads to your List Manager, it would also consume 200 API calls. However, there is a 24 hour grace period. The grace period means analyzing the exact same data more than one time during 24 hours will not consume more than one API call.

The free plan gives you 2000 API calls every month. If your API calls remaining goes to 0, you can no longer validate any emails or add new leads to List Manager. In this case you must either upgrade to a monthly plan, buy a one time package, or wait until the beginning of the next month to receive the new set of 2000 free API calls provided by the free plan.

Monthly API plan – This is the minimum number of API calls provided by your subscription plan each month. For example, if you have the Silver plan it provides you with a minimum of 20 000 API calls to use each month, as long the subscription is active. Unused API calls from a monthly API plan will not be moved on to a new month while unused API calls from a one time package will be moved.

If you buy a one time package, the API calls remaining counter gets increased by this value. Every first day of the month, if your API calls remaining is smaller than your Monthly API plan’s value, then your API calls remaining will be set to the value of the Monthly API plan.

For example, if you upgrade from the free plan to the Silver plan, your API calls remaining will be updated to 20 000 after the payment is received. If you use 1000 API calls (e.g. analyze 1000 emails or add 1000 leads to the List Manager), your API calls remaining will drop to 19 000. At the first day of next month, your API calls remaining will be updated back to 20 000, as long as the Silver plan subscription is active.

Or, if you upgrade from the free plan to the Silver plan, your API calls remaining will be updated to 20 000 after the payment is received. If you then buy the 50 000 one time package your API calls remaining will be updated to 70 000. If you use 1000 API calls, your API calls remaining will drop to 69 000. At the first day of next month, your API calls remaining will stay at 69 000, because it is still higher than the monthly calls of the Silver plan. If you then use 60 000 API calls your API calls remaining will drop to 9000 calls remaining. At the first day of the next month, your API calls remaining will be updated to 20 000 API calls, as long as the Silver plan is active.