Frequently asked questions

Need additional information ? Here you will find the developed answers to your frequently asked questions about our service. If you do not find an answer to your question, please do not hesitate to contact.

General questions

If you created an account using an email address, we have sent a confirmation link to that address. If you cannot find your confirmation email: Check your spam folder for spam. Make sure you've entered the correct email address.

CaptainVerify is an online service only. There is no software to download.

Verifying your data ensures that you send emails to your contacts that will not result in a bounce. For more information see our article: Clean your mailing list: The 10 important reasons.

No, Captain Verify does not send email or SMS on behalf of its customers and will never send email.

Yes, Captain Verify processes emails from around the world, consumer and business addresses with great precision. This includes verification for all major ESPs, but not just for Yahoo, Gmail, Hotmail, Outlook, etc.

No! CaptainVerify is a paid on demand service. Simply sign up and pay for the checks you use. CaptainVerify prices can be found on our home page

CaptainVerify monitors each account for specific behaviors that have been correlated to the misuse of the service (read the Condition of Use). When we observe these behaviors, we deactivate the account. To reactivate your account, please send a message via our contact form and we will respond quickly.

Yes, you can invite new users of your team to manage your checks / APIs. See you on your Dashboard: My Account> The team.

If you have not found the answer to your question in the FAQ or documentation, you can contact us via the contact form. We favor exchanges by email and we do not offer telephone support. As a general rule, messages will be answered in less than 24 hours (excluding weekends) GMT+1.

Questions about our service

A verification will precisely determine whether an email address is active or not. 1 verification = 1 email verified

Yes, after creating your account, you can generate your API key and integrate CaptainVerify in your own applications.

We accept CSV files. If you need help formatting your file in CSV format, please visit this link. To properly prepare your file, please open it in Excel, make sure all the email addresses are in the same column, click Save As and select Format > Comma Separated CSV Values, and save your file.

No, your file must contain only one column with email addresses.

You can put up to 1 million lines per email file for CaptainVerify. If your file exceeds the line limit, please split the file into multiple files.

Your file must be imperatively in CSV comma separator format. For more information, please see our section on Convert a CSV.

For the best deliverability results, you should only send to valid emails. This is especially true if you are using email providers like MailChimp, Mailjet or Sendgrid ... For more information on how to use each Terminology, please see our page: Terminology.

When your cleaning is finished, you can click on the "Download valid" button on your dashboard. If you want your file checked, just click the "Download All" button directly.

It is likely that an additional delimiter was included with each email address in your file. For more information on how to prepare your file for verification, see our Convert a CSV.

Questions about email verification

Our exclusive multi-step verification process checks each email up to several times from different locations around the world. We use, MX, DNS, SMTP, and other private technologies to determine the validity of addresses. CaptainVerify offers free deduplication and syntax error checking.

The treatment time varies depending on the number of emails in your list. On average we process 10,000 e-mails between 1 and 2 hours. For a Mailing List of 100,000 addresses The verification can be done in less than 8 hours. For 1,000,000 it takes at least 2 days. It will depend on your file and the overload of the service. Don't worry if it takes a time, it's normal.

Yes, CaptainVerify helps remove primary spamtraps. As certain types of traps like honeypots can be identified by CaptainVerify. And other disposable emails are valid for a period of time.

Do not worry, the system performs a double check on certain addresses and the formatting of the file can take time and this is quite normal.

Sometimes a misplaced space or comma can cause the file to slow down. Give the system a few minutes.

  • If your file is "blocked" at 0%: do not worry, the system must analyze your file and depending on the number of lines, it can take time.
  • If your file is "blocked" at 96%: do not worry, the system performs a double check on certain addresses and the formatting of the file can take time and this is completely normal.
  • If your file remains blocked for more than 60 minutes: please use the contact form to send a message to one of our collaborators.

Greylisting is a technique that some messaging servers use to combat spam, which allows the server to know if you are legitimate. This is a temporary blocking process of incomplete incomplete emails (soft bounce) instead of letting them reach the reception box directly. If you send an email to a messaging server for the first time and it is on the gray list, you receive a temporary error code. If the email is rejected, you can try to return it after a few minutes (15 minutes by default).

The Captain Verify team has deployed an anti-Greylisting technology which will make your emails more reliable than ever! We don't want to make you miss opportunities, which is why we wait 30 minutes before reducing a check. Thus, your emails will not be lost in the mass.

For more information on each of our primary and secondary terminologies, please see our page: Terminology.

Regarding unknown email addresses "Unknown": it is that the remote server does not respond in time. We have not received a clear answer for independent technical reasons of our will: slow / bad configuration of the server, antispam protection for the verification goes into "unknown".

What to do ?
  • You can delete qualified addresses such as: Role, Disposable, risky, OK for All because it will cause quality problems such as bounce and / or a bad opening rate.
  • You can redo a new list and reverify only unknowns in CaptainVerify.
  • You can also add 3/4% of unknowns to each marketing campaign to not impact your deliverability. If you see that the bounce rate is low you can increase the% unknown. This will allow you to segment your base and control your bonce rate with each send.

For your marketing campaigns, avoid sending emails to the invalid, disposable, role and, in some cases, to the Catch-All addresses. It is also not recommended to use diffusion lists purchased online. By using our services, you will benefit from complete documentation on the statutes and the qualification of email addresses to optimize your campaigns.

Questions about verification of mobile numbers (HLR)

Our verification service HLR lookup allows you to identify the IMSI number attached to the mobile number and know if a mobile phone number exists and which operator is attached the corresponding subscriber (MCC & MNC).

The processing time varies according to the number of mobiles numbers in your list. On average we process 1,000 checks between 10 and 15 minutes. Check the validity of your mobiles numbers.

We only accept mobile numbers in international format. (447....)

You must always add the country's international indicative when you want to check a phone number. For example, if you have a mobile phone form the UK: "07988756241", you must add "+447...", which is the international indicative of the UK, in order to make your number compatible. Discover our user manual on How to convert a number in international format.

We cover more than 100 operators on 16 countries: The list is available on the documentation HLR lookup

The modified numbers / "Converts" are generally overseas numbers our system automatically converts numbers to international E164 format. For example, number 336... If it is a Martinican number, it will be converted with the Martinican indicative, 596 which will give: 5966...

A number that alternates between invalid/valid is regularly unreachable, probably because of an airplane mode or simply because the phone is in a place out of network coverage can be given invalid by the register and we cannot remedy it.

HLR registers are made available by operators. They have the legal obligation to provide an up-to-date HLR register, but some operators can give false positives, because they are not up to date.

Security & Privacy

Your data is always yours and will never be shared. We archive your data on your dashboard, but you can delete it permanently at any time. We strive to secure all user data and use the latest security standards. Your files and checks are stored for a period of 90 days and are then automatically deleted from your account and from our servers.

Our storage servers are located in France (OVH) compliant with GDPR and certified ISO 27001 / SOC 1,2,3. All transmitted information is protected by SSL / TLS 256 bit encryption.

You have the right to delete your account: go to your Dashboard and click on My Account > Personal Data. Once you have deleted your account, all your personal information, your files, your checks will definitely be deleted from Captain Verify. Billing and invoices will be saved.

Captain Verify is RGPD compliant as of May 25, 2020. Our business aims to protect our users' data, you can also read our Privacy Policy and our Terms and Conditions


Captain Verify offers to buy on demand checks at a reduced price. This is useful, for example, if you have 4 mailing lists of 5,000 addresses. Instead of buying 4x 5,000 checks for $ 120 (excl. Tax), you can buy 25,000 checks for $ 75 (excl. Tax). You save $ 45. It's 64% off!

Credit by monthly subscription has many advantages that are worth it. To start, you benefit from a 10 % reduction with monthly payments and 2 free months with a single annual payment. This is a considerable economy, especially if you plan to subscribe for several months.

Without subscription Captain Verify will bill you only for your needs. Prices start at $ 7 (excl. Tax) for 1,000 email checks. You can view our Prices on our home page

For credits on demand : File processing will be paused. We will send you a notification by email and on your dashboard so that you can re-credit your account to complete the verification. We advise you to register a means of payment. This simply allows you not to have to re-enter your information with each order and to have an almost continuous service.

If your credits with your subscription are exhausted. You must wait until the following month or you can change your subscription or order credits on request so as not to interrupt your checks.

We accept: Visa, MasterCard & Paypal. The payment system is secured by Stripe. Your information is stored securely on the servers of our payment partner and does not pass through our platform at any time.

When you have made a payment you will receive an email confirming your payment (with your invoice in PDF) or you can log into your account and click on My Account > Invoices.

For demand credits: the checks ordered can be used for a period of 365 days from the order. You can lengthen this period by making a new order before this date. Expired credits can not be the subject of a report, a credit or a refund.

For credits with subscription: unused credits are not carried over to the following month. If your needs change, you can always go to another subscription or order credits on demand.

If you have a subscription with a monthly payment, your bank may require a 3D SECURE verification as a safety measure to validate your monthly payment. If you do not confirm your payment within 3 days, your subscription will be canceled.

Have you tried to order on Captain Verify but your credit card has been refused or failed? There are many possible reasons for a credit card malfunction. But before contacting your bank, remember to check some things first.

If the payment is refused, there may be several reasons:

  • You have entered incorrect data
  • Your card has a problem and your bank is blocking payment authorization
  • A lack of funds
  • The 3Dsecure of some banks is not functional
Regarding your credit card number, with impatience, it can happen that we are wrong. You must verify that you fill in correctly:
  • the 16 digits of your card (without spaces)
  • the validity date (ex: 03/23 for March 2023)
  • CVV: 3-digit security code (on the back of your bank card)
If all of this information is correct and the payment is declined, there is a problem with your card and you should contact your bank. It may be a blocked card, not activated or whose maximum limit has been exceeded. You can possibly try again in the next 24 hours or You can use Paypal (no need to have an account).


If your ESP (mailjet, mailchimp) asked you to check your mailing list, it is likely that your e-mail database has a high number of invalid addresses which must be deleted before making your next campaign. CaptainVerify helps identify and remove invalid email addresses from your databases.

You have checked your list with CaptainVerify but when importing from Mailchimp you have an Omnivore Warning alert because some of your addresses are still at risk. You should know that Mailchimp refuses role type emails: contact@, info@... You must therefore remove role type addresses from your list and the import problem will be solved. More information on Omnivore Warning on our blog.

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