How to Use Email Validation API in the G-Lock Email Verifier

This tutorial explains the steps to take to verify email addresses through the integrated BPSocks API in the Advanced Email Verifier. It is assumed that you are already familiar with the software and how it works generally such as installation, creating a list, importing email addresses etc.

In order for you to effectively use a desktop email verifier on your system, you need access to SMTP port 25 and a properly configured and authenticated SMTP IP/hostname such as reverse DNS, Forward Confirmed Reverse DNS, Clean IP reputation, SPF etc because many ISPs/ESPs are known to reject validation requests from the IP address that lacks the mentioned properties.

To overcome these challenges, we have partnered with the service to provide a powerful and high speed email validation API service (Application Programming Interface) and starting from version 8.1.0 of the Advanced Email Verifier you can now verify emails using the integrated BPSocks email validation API.

You can use the BPSocks email validation API when:

  • your Internet Service Provider is blocking access to the SMTP port 25;
  • you can't verify emails through the web script;
  • you can't install the Advanced Email Verifier on a Windows server or Windows VPS with proper SMTP emulation authentication/integrity properties such as Reverse DNS, Forward Reverse DNS, SPF, Valid HELO identifier, clean IP reputation, Greylisting etc.

Download “How to Use Email Validation API” Guide as PDF

Benefits of Using BPSocks Email Validation API:

  1. proper SMTP server emulation properties such as SPF, DKIM, FCRDNS, Valid HELO identifier that allows you get a high accuracy of the verification results;
  2. ability to verify email addresses from the Hotmail and Live domains that check the user's IP address for Forward Confirmed Reverse DNS records;

What is checked by email validation API (in progressive order):

Email syntax – this checks the email addresses syntax and ensures that they conforms to IETF standards.

Fake Email Pattern Detection – this checks the email address against a powerful in-built fake email pattern detector algorithm. This fake email pattern detector is capable of detecting thousands of fake email automatically with very high accuracy.

Typo Check and Curse Words Check – this checks the email address against all known common typos for most email domains. The API can also detect certain curse words present in the email address.

Mail Server Existence Check – this checks the availability of the email address domain using DNS MX records.

Mail Existence Check – this checks if the email address really exists and can receive email.

Catch-All Domain Email Check – this checks if the email domain will receive all of the email messages addressed to that domain, even if their addresses do not exist in the mail server.

Disposable Email Address Check – this checks if the email is provided by a known Disposable Email Address (DEA) provider such as Mailinator, 10MinuteMail, GuerrillaMail and about 2000 more.

How to Use BPSocks Email Validation API

Follow the steps below to verify emails through BPSocks email validation API:

Navigate to the Home menu in the Advanced Email Verifier and click on Settings.

Click on the Connection tab in the program Settings.

Check the "Connect through BPSocks Email Validation API" option.

Click on the “Buy API Key” button.

On the ordering page choose the package that best suits your mailing list size. After your order is complete you will receive the validation API key via email. The API key is required to authenticate you to BPSocks email validation API.

Before you go with the paid API key, you can request the trial API key for 500 email addresses to test how it works.

After obtaining your API key, copy-paste it in the “Validation API Key” field.

Click on the "Quota Check" button to see your quota and make sure your API key is valid.

Automatically recheck “Unknown” emails (times) – you can use this option to automatically re-try a few times “Unknown” email addresses with the following statuses:

Unable to get response from API

BPSocks has the automatic credit refund for “Unknown” statuses with the above errors.

After entering the API key and checking the current quota, click on the Rules tab in the Settings.

The Advanced Email Verifier comes with default rules to exclude the validation of emails from certain free email providers such as and to prevent your IP address from being blacklisted by these providers. With BPSocks API, you will not have any issues validating emails from these free email domains. Therefore, you can delete the rules for these domains from the program Settings.

It is strongly recommended that you keep the rules for the* domain and "role addresses". The email addresses from the* domain cannot be verified without sending a real message to the user. And “Role email addresses” should be automatically marked as Bad by the verifier because the presence of such emails in your list is normally regarded as an indication that your list may be purchased or scraped. Hence, if you upload such list containing such emails, the list will be flagged and your account may be suspended.

Click on OK to save the Settings.

Navigate to the Home menu and enter your desired number of connections for multi-threaded validations. BPSocks API can support up 1000 instantaneous connections which is the limit in the Advanced Email Verifier. The default timeout settings which is 30 seconds has been tested to be ideal for good network connections.

Important! It is recommended to verify email addresses slowly because a lot of mail servers start throttling connections if they see a high volume of connections coming from the same IP address. It results in rejections and errors during verification. Thus, we recommend to set no more than 50 connections in the Advanced Email Verifier and …be patient!

set connections and timeout

After the number of connections and timeout are set, click on the Start button to start validating emails.

start verification through API

After some time, the program will display the verification results with the corresponding response codes for each email address validated.

view verification results

When the validation process has finished, save or export only email addresses marked as “Good” to reduce your bounce rate to minimum.

save good emails to a file

How to Get Accurate Results and Save Points Using BPSocks API

The Advanced Email Verifier supports the fast checking mode when it verifies only the domains for validity. The fast checking mode does not depend on the port 25 and works even if the test of the direct connection mode fails in the Advanced Email Verifier Settings.

With that said, you can check your list in the fast checking mode the first time, delete email addresses marked as “Bad” and then run the second check using the BPSocks email validation API. Here are the steps to follow:

1. Go to Settings -> Connection.

2. Choose the “Direct Internet connection” mode and click OK.

3. Check the “Fast checking (DNS query only)” option on the Advanced Email Verifier menu bar.

4. Click “Start” to start the verification.

5. Delete “Bad” emails after the verification is complete (Clear -> Bad) and uncheck the “Fast checking (DNS query only)” option on the menu bar.

6. Go to Settings -> Connection.

7. Choose the “Connect through BPSocks email validation API” mode and click OK.

8. Click “Start” to re-check the list.

9. Save or export “Good” email addresses after the verification is complete.

Is it possible to verify ALL emails through BPSocks API?

Although BPSocks API has a very good email validation success rate with most free email ISPs or ESP, it is simply not possible to guarantee a 100% accuracy level due to certain multiple factors beyond our control. The level of accuracy you can obtain depend on the inbound SMTP connection policy of the remote ISP or ESP, reputation of the incoming connecting IPs and many other factors.

The email addresses which could not be verified due to one reason or the other are marked by the program as "Unknown". These unknown results in most cases results from Greylisting which is technology that reduces spam by rejecting initial email delivery attempts. The Greylisting works by returning a "Temporarily Unavailable" message to the sending mail server the first (and only the first) time a message is received from a given sender. Hence, it makes sense to retry these validations again after some time has elapsed.

In addition, "Unknown" results can also result from the inability to verify the emails by simulating a message sending to the recipient email server because the recipient email server requires that a REAL message is sent. Thus, it is impossible to verify whether the address is good or not. You won't know definitively until the message bounces because these mail servers won't cooperate or cannot be checked without sending a real message to them.

To address this issue and save your API requests, we added certain domains that have been known to often refuse email validation attempts to the Rules settings in the Advanced Email Verifier in order for the program to automatically mark all emails from such domains as "Unknown". Therefore, if your email lists contains email addresses from such non-cooperating email domains, the program may not be able to offer you 100% validation success. The success rate does fluctuate and there is no fixed guarantee.

To accommodate for this, the Advanced Email Verifier includes an in-built bounce handling module that can be used to process the bounced emails to the unknown results list.

Recommended Practices for Dealing with Unknown Results

The following practices are strongly recommended to deal with the Unknown results reported by the BPSocks email validation API:

1. Since a majority of the unknown results are caused by temporary issues (Soft Bounces) such as SMTP server timeout or downtime, Greylisting, Mailbox size exceeds quota, temporary mailbox suspension/deactivation, and temporary blockings due to IP reputation, it is strongly recommended to re-validate Unknown email addresses again at a later time. We do not recommend deleting the Unknown emails immediately after running the verification. Chances are that emails which previously were returned as Unknown will be verified as Good.

2. Review all the failure status codes for the Unknown emails to know why each email address in the Unknown list could not be verified as valid or invalid. You may use your discretion to delete only those emails belonging to a status code which are more likely to indicate invalid emails and leave the rest.

3. After pruning the unknown list as explained above, you may then proceed to save the Unknown emails to a file. They can be later used for your email campaigns. We strongly recommend that you use the Bounced Manager module of AEV to process bounce emails and have them removed from the list.

Using Verified Emails in Third Party Email Delivery Services

Many companies and email marketers are now using third party email delivery services to handle the delivery of their transactional and marketing emails. By using a professional third party email delivery service, a higher inbox placement or delivery rate can be achieved. These third party email delivery services have relationships with various ISPs/ESPs and also provide strict acceptable “Bounce Rate” threshold for those who use their service to avoid being labeled as a server that delivers spam.

Although, the benefits of using a third party email delivery service is obvious, extreme care must be taken in order not to exceed the acceptable or permitted “Bounce Rate” for any email campaign you send through their platforms. Bounce rate is simply the percentage of emails that is returned undelivered when you send out your campaign. Although most third party email services do not explicitly specify their bounce rate limit, the average acceptable bounce rate is 5%. If you exceed this rate, your account is suspended or deactivated. In most cases, these third party email delivery services are required by ISPs/ESP and Spam Advisory Groups such as Spamhaus to enforce the bounce rate thresholds and suspend any account that exceeds these thresholds in order to prevent Spam.

To avoid your third party email delivery service account suspension or deactivation, it is important that you adopt the following best practices before importing your cleaned emails into your third party email delivery service:

1. After validating your list, save only the VALID emails marked by the verifier. Do NOT add the emails marked as Unknown to the valid emails. As a rule, never upload the Unknown emails to your third party email delivery service.

2. Save the Unknown emails to a separate file and send the message to the Unknown emails using a private SMTP server. Approximately in 24-72 hrs, use the bounce handler to read all bounced emails, extract the email addresses and collect them in a text file. You can then download the file and subtract them from the Unknown list you downloaded from the verifier.

3. Some email addresses marked as Valid by the verifier may not be Valid in reality. This false positive is caused by a strict anti-spam technology employed by some ISPs notably Yahoo. With Yahoo in particular, deactivated/suspended/expired emails are marked as Valid by the verifier because Yahoo regards these emails as valid or “existent” even though such emails are not active and cannot receive messages. Hence when you attempt to send your campaigns to such emails, they will bounce because the emails are not active.

Thus, before using the valid emails downloaded from the verifier, it is strongly advisable to remove all Yahoo emails from the list. You can save the yahoo emails to a separate file and add them to the Unknown emails. Send a message to the Unknown emails using your private SMTP server and after that use the bounce handling feature of the Advanced Email Verifier to process the bounces to such emails.

Here you can learn how to use the Bounced Manager module of AEV to process bounce emails

Download “How to Use Email Validation API” Guide as PDF


Acceptable Use Policy: Our Advanced Email Verifier is NOT to be used for verifying email lists extracted from the Internet as well as generated email addresses as this is against our acceptable use policy. Using the Advanced Email Verifier to verify such email lists will result in your API key being blocked and you will risk your license terminated. You are strongly advised to use the Advanced Email Verifier to validate your own opt-in email lists only.