Email Verification

By Whois XML API | Updated 12 days ago | Database

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For a given email address:

  • Format check
  • SMTP check
  • Domain name system check
  • Free email address check
  • Disposable email address check
  • Catch all email address check
  • Mail exchanger records
  • Record update dates

How to use
Check our Email Verification API docs for more information. You can find code examples in various programming languages on GitHub.


  • Comprehensive validation of email addresses in real-time and conveniently
  • Easily integrable and RESTful API, compatible with all major programming languages
  • The query results are returned in XML & JSON with parsed fields and raw texts

Use cases

  • Avoid email bouncing and increase your sender score and email campaign quality
  • Verify email address of new user registrations, notably ensuring that users can reset their password securely if forgotten
  • Allow users with real, verifiable personal or business email addresses only to register
  • Reduce the risk of website freemium abuse
    Ensuring the users who sign up on your website have a valid and verified email address is valuable for a number of reasons:
    • Catch user typos with email validation when they’re entering their email address and prompt the user to fix typos before allowing them to register.
    • Lets you stay in touch with your users knowing you have a verifiable email address for: credit card expiration, receipts, new features and offerings, etc.
    • Ensures that your users can reset their password securely if forgotten: without email address verification and validation, there’s no way to validate someone’s identity outside of manual human verification.
      Prevent users from signing up for your website with disposable email addresses using our email validation API tool. Users who sign up for these services are usually try to bypass giving you their real email for a specific reason: maybe they want to abuse your freemium features, etc.

By ensuring you only allow users with real verifiable personal or business email addresses to register, you reduce the risk for abuse on your website.
The e-mail verification API by WhoisXML API, INC. provides information
for the verification of e-mail addresses.

Here we describe the interpretation of the query result in detail.

The query result is available in JSON or XML formats and contains the
following fields:

  • emailAddress: repeats the address which is to be verified
  • formatCheck: Lets you know if there are any syntax errors in the email address. This is a basic check performed in order to catch any simple typos or major errors. This value will be ‘false’ if there are no errors, and ‘true’ otherwise. Behind the scenes, the API service is handling all these types of verification checks for you in a number of relevant ways.
  • smtpCheck: Check if the email address exists and can receive emails using SMTP connection and email-sending emulation techniques. This value will be ‘true’ if the email is exists and can receive email over SMTP, and ‘false’ otherwise. May be ‘null’ for invalid or non-existing emails.
  • dnsCheck: Ensures that the domain in the email address, eg:, is an existent and valid one. This value will be ‘true’ if the domain is good and ‘false’ otherwise. May be ‘null’ for invalid or non-existing emails.
  • freeCheck: Check to see if the email address is from a free email provider like Gmail. This value will be ‘true’ if the e-mail address is provided by a free provider and ‘false’ otherwise (that is, typically, if the address is provided by an organization, company, etc.). May be ‘null’ for invalid or non-existing emails.
  • disposableCheck: Tells you whether or not the email address is disposable. Disposable e-mail addresses are provided for users who do not want to provide their real contact to websites or services. They are typically deleted after a few days of their registration. There are providers specialized for such services, such as, e.g. Mailinator. This check helps you in fighting abuse or preventing to send e-mails to non-permanent e-mail addresses. The return value will be ‘true’ if the email is disposable, and ‘false’ if it is a permanent one. It may be ‘null’ for invalid or non-existing emails.
  • catchAllCheck: Tells whether or not this email address is a “catch-all” address. This refers to a special type of address that can receive email for any number of other addresses. This is common in businesses where if you send an email to and another email to, both of those emails will go into the same inbox. Possible values are ‘true’ (it is a catch-all address) or ‘false’ (otherwise). Can be ‘null’ for invalid or non-existing emails.
    mxRecords: Mail servers list. These are the actual servers which will
    handle the e-mails directed to this address. Possibly absent for
    invalid or non-existing emails.
  • audit: a structure of two fields:
    • auditCreatedDate : the creation time of the cached data
      on which the analysis is based on.
    • auditUpdatedDate: the time of the last update of the cached data
      on which the analysis is based on.