FAQ

General Questions

Do you offer a free trial?

As a cloud based self-serve platform, we do not offer a free trial. However, we do have a trial package available! It is 500 credits for just $5.00. Using this trial package, you can fully test all of Email Checker’s services for relatively no risk at all.

Does Email Checker send emails to verify email addresses?

No, Email Checker services perform a simulated SMTP test at best. The verification test will connect to the mail server, perform a certain set of commands to ask if the mailbox exists and then gracefully disconnects after receiving the reply. Email Checker’s verification tests does not have the functionality to send an email to anyone at anytime in anyway.

What exactly can Email Checker detect and handle with email addresses?

We detect dupes, typos, invalid syntax, invalid domain DNS, invalid MX DNS, disposable addresses, role accounts, free email providers, frequent complainers, offensive words, spam traps, honey pots, blacklists, catchalls, greylistings, mailbox exists, mailbox full and mailbox does not exist.

In summary, we can detect anything that may bounce and hurt your sender score. We help you keep your accounts in good standing with the Email Service Providers and help your Email Campaigns reach the inboxes of your customers instead of their spam boxes.

Which tests are performed on email addresses that I verify?

    Addresses are checked for being in a valid RFC compliant format.Addresses are filtered against all blacklists.
    Addresses are checked for having a valid domain dns and mail server dns.
    Addresses are filtered for spam traps and honey pots.
    Addresses are checked up to 5 times total through an simulated smtp test to check if the mailbox exists and can receive email.
    Addresses are filtered for disposables, frequent complainers, offensive words and more.
    Addresses are checked for mailserver location and typo’s.

How do I download my list after it has completed processing?

After your list has completed processing, there will be a new, blue button labelled “Export” in the table below the “Drag and drop” box on the Bulk Email Verifier page. When you click Export, it will display a dropdown menu containing the supported export options for this list.

The supported Export options include All Results, Deliverable Only, Undeliverable Only or Unverifiable Only. You can select an option to download a CSV file containing the email addresses with the chosen status.

The CSV file will contain additional columns beyond just the email address so you can understand what our system detected and why it considered the address to be deliverable, undeliverable or unverifiable.

Why are some of the addresses I verify returned as Unverifiable?

Not every mail server is compatible with Email Checker’s tests. We have 3 types of Unverifiable responses that are encountered in which makes the address unable to be verified.

Is catchall – A catchall mail server is configured to accept email regardless if the mailbox exists or not, rendering the test inaccurate.

Is greylisting – A greylisting mail server is configured to deploy an anti-spam technique which adds an automatic delay to mailing and is not compatible with Email Checker tests.

Transient error – A transient error is a temporary network error which may be the result of high mail server load, mail server misconfiguration or even forceful disconnects. We suggest to retry all transient error addresses at a later time allowing the mail server to regain its functionality.

Unfortunately neither Email Checker nor any other email verification service can test these address types, the issue is directly in how the mail server is configured that prevents the test from working.

Is catchall & Is greylisting responses are considered permanent as they will never return a Deliverable/Undeliverable response when retried unless the mail server changes their configurations. Transient error responses are considered temporary and we suggest to retry these at a later time.

We recommend to send emails to the deliverable addresses only. However if you choose to send to the unverifiable addresses as well, we advise adding small batches of the unverifiable addresses while sending emails to the deliverable addresses and then manually handling any bounce events that may occur.

If I send emails to Unverifiable addresses, will they count against me in anyway?

It is 100% unknown if “Unverifiable” addresses exist or not. Emails are flagged as Unverifiable when the system cannot perform an SMTP test on the mail server. If you sent 100 emails to Unverifiable addresses, it could result in a 100% delivered campaign or a 100% bounced campaign. Unverifiable addresses will not consume any credits from your account.

We recommend to only send emails to the Deliverable addresses. However, if you choose to send to the Unverifiable addresses as well, we advise adding small batches of the Unverifiable addresses while sending emails to the Deliverable addresses and then manually handling any bounce events that may occur.

Should I reprocess my Unverifiable addresses over and over?

You can indeed reprocess your Unverifiable addresses over and over in the attempt to pull out more Deliverable/Undeliverable addresses. However, not all types of Unverifiable addresses are able to be reprocessed.

Is catchall – Is catchall addresses will always receive the same permanently unverifiable response.

Is greylisting – Is greylisting addresses will always receive the same permanently unverifiable response.

Transient error – Transient errors are temporary network errors and may return a Deliverable/Undeliverable response when retested.

After a certain amount of reprocessing, you will experience diminishing returns in which you will no longer retrieve any more deliverable/undeliverable addresses from the list.

What exactly is the 97% deliverability guarantee?

EmailChecker.io guarantees that when sending email to an eligible Deliverable list of at least 100 addresses, there will never be more than a 3% maximum bounce rate.

1. List must contain at least 100 addresses and sent within 48 hours of validation completing.
2. List must contain the Deliverable addresses only. Undeliverable and Unknown addresses are not eligible
3. Eligible bounces are invalid (mailbox does not exist) addresses only.

If you feel we have not delivered the service we have guaranteed, please contact us at service@emailchecker.io to open a claim.

What is the Undeliverable Blacklist?

The Undeliverable Blacklist is a blacklist that tracks all of the email addresses you have verified through Email Checker that returned a Undeliverable result. When you verify emails, they are filtered against the Undeliverable Blacklist and if found, are marked as Undeliverable for free. This system helps save costs by ensuring you only pay to verify a Undeliverable address once. You can view/edit/delete all addresses added by browsing to the Blacklist section in the left sidebar menu and then selecting Undeliverable Blacklist. Additionally, you can disable this blacklist entirely in your account settings by clicking the green toggle button for the Undeliverable Blacklist Filter.

What is the Custom Blacklist?

The Custom Blacklist is a user maintained blacklist in which you can add email addresses that you have encountered and do not wish to send email to. After you add the addresses in your Custom Blacklist and are verifying emails, they are filtered against the Custom Blacklist and if found, are marked as Undeliverable for free. This system helps keep your lists clean by preventing known troublesome addresses from making their way back into your lists. You can add/view/edit/delete all addresses added by browsing to the Blacklist section in the left sidebar menu and then selecting Custom Blacklist.

What is the Domain Blacklist?

The Domain Blacklist is a user maintained blacklist in which you can add domains that you have encountered and do not wish to send email to any mailboxes on the domain. After you add the domains in your Domain Blacklist and are verifying emails, they are filtered against the Domain Blacklist and if found, are marked as Undeliverable for free. This system helps keep your lists clean by preventing addresses on known troublesome domains from making their way back into your lists. You can add/view/edit/delete all addresses added by browsing to the Blacklist section in the left sidebar menu and then selecting Domain Blacklist.

Can you provide an invoice for my purchase?

We do provide invoices and they can be found on the Purchase page. Please scroll down to the bottom of the page to the transaction history section and find the transaction you need an invoice for, then simply click the Print Invoice button for it to be generated for you.

Where are your servers located?

Email Checker servers mainly operate out of New York City. However we have multiple control panel servers located in the cloud at New York City, Atlanta, Norfolk, Chicago, San Francisco, Seattle and Dallas. We have numerous verification servers on each continent to provide the fastest results possible wherever you are in the world. These strategically placed geolocations keep our services running as fast and reliable as possible, true enterprise grade email verification.

Bulk Email Verifier Questions

Do I need to leave my computer on if I am using the Bulk Email Verifier system?

All email addresses are verified directly from Email Checker’s cloud server cluster. Feel free to sign out from the control panel, logoff your computer or even shut it down altogether. Your lists will continue to process 24 hours a day, 7 days a week on our cloud servers until complete.

How fast is the Bulk Email Verifier system?

The speed in which our cloud servers verify email addresses varies, but a good expectation is around ~100,000 per day, per list.

The estimated time for completion that we provide is simply an estimate based on the amount of emails in the list and MX server average response times.

The only bottleneck in our validation system is the speed in which the receiving mail server that is being validated can respond to our requests which can range from just milliseconds up to 120 seconds at which point we forcefully timeout.

I imported a new file, but the system did not recognize all email addresses in the list?

This is usually due to either the files formatting or structure in general. Your file can include up to 100 columns of data or just 1 column of emails. Your file must be in plain text formatting and no larger than 10mb file size. Please split larger files into multiple smaller files to accomodate this limit. Please see the following example of how your data should be structured.

email, first name, last name
janedoe@gmail.com, Jane, Doe
johndoe@gmail.com, John, Doe

If your file is in the correct format & structure and you are still having problems, please feel free to contact us atservice@emailchecker.io. Please be sure to include a copy of the file you are having problems with. Our friendly customer support team will happily review the file and let you know exactly what has gone wrong.

Why is my Bulk Email Verifier process taking longer than estimated?

The estimated time for completion that we provide is simply an estimate based on the amount of emails in the list and MX server average response times. The only bottleneck in our verification system is the speed in which the receiving mail server that is being verified can respond to our requests. If you are processing a list containing all top name providers such as @gmail, @hotmail, @yahoo and etc. who respond in just milliseconds, you can expect the list to process quicker than estimated. If your list contains many small private email servers that can take up to 120 seconds to process, at which point we timeout, you can expect your list to take longer than estimated.

If your list contains a high rate of Undeliverable or Unverifiable email addresses, this can slow down your list processing speeds as both responses take longer to validate than a Deliverable response.

If your list is a large list consisting of addresses mainly on the same mail server, EmailChecker.io may throttle your list to prevent both, damage to our verification servers and service interruptions for other clients.

Privacy / Security Questions

Do you store any of my email addresses?

We do store email addresses in some instances, but only what is necessary for the service of your account. Your imported email lists in the Bulk Email Verifier system are stored until they have completed and you delete them or 90 days, whichever comes first. Undeliverable addresses are stored in your Undeliverable Blacklist to prevent future verifications being used to verify the same address twice, again until you delete them. The Custom & Domain Blacklists store all data you have inserted until you delete them. The 3rd party Blacklists (Mailchimp , Mailjet and etc) will store any addresses added until you delete them. We do not store any information you do not want us to store and if you delete it from your account it is 100% deleted and unrecoverable.

We also log email addresses verified by each account for 10 days in an unrecoverable hash for the sole reason of deliverability guarantee claims. Email addresses verified via our services that are accuracy guaranteed events are stored in a SHA512 (Email Address + Salt) hash for 30 days. When a claim is received Email Checker will perform the same hash method on the email address(es) in the claim to compare against the data logged from the api key to extract the results of that specific verification test.

Email Checker staff will never actually see your data, only the statistics of your data such as exists or does not exist and any error messages associated in the efforts to increase the quality of Email Checker services. The client or authorized users data is sent over secure HTTPS connections and is encrypted using 2-way encryption methods while communicating with the verification servers to ensure the data stays safe at all times. Email Checker does not sell, share or use your data in anyway other than to provide the service of verifying email address(es).

How secure is my information on your servers?

We understand your data is extremely important and security is at the top of our list. Email Checker deploys multiple security methods which are up-to-date security standards which means your data is as safe as possible with current technology. Email Checker is behind a Secure Socket Layer, all data you transmit to the website is hidden behind 256-bit encryption. All files that you upload to your account are stored in an independent container that only your account can access. Additionally, all data sent between our servers and stored is encrypted via our in-house 2-way encryption methods that ensure your data stays safe at all times.

Have a question that you couldn’t find the answer for in our frequently asked questions? Please send us a message and we will respond via email as soon as possible.