Introduction to the MailboxValidator API



The MailboxValidator Single Validation API is an easy to use RESTful API that allows users to programmatically validate a single email address. This is useful for programmers who want to have email validation functionalities in their own programs or websites.

If you are unfamiliar with the term RESTful, you should read up on REST below:


To use the API, you will need to sign up for an API key. If you haven’t done so, just go to the API plans page and sign up for the free API plan.

Basic usage


<your API key>


<json or xml>

There are basically 2 parameters when doing a GET call to the API. The email parameter is the email address that you wish to validate while the key parameter is the API key that you should have signed up for in the pre-requisite section above.

You may have noticed that there is a third parameter format. This parameter is optional and has a default value of json. Therefore the API will return results in a JSON string unless otherwise specified.


If you didn’t specify the format or you chose json, you will see something like below:

  "email_address": "",
  "domain": "",
  "is_free": "True",
  "is_syntax": "True",
  "is_domain": "True",
  "is_smtp": "True",
  "is_verified": "False",
  "is_server_down": "False",
  "is_greylisted": "False",
  "is_disposable": "False",
  "is_suppressed": "False",
  "is_role": "False",
  "is_high_risk": "True",
  "status": "False",
  "credits_available": 297,
  "error_code": "",
  "error_message": ""

If you chose xml explicitly, then you’ll see the below:


Whichever format you choose, the results are still the same. So select whichever works best in the programming language that you need.

For more info on the API, check out the API documentation page.

Auto renewal

The MailboxValidator API plans are all operating on a 30-day cycle. This means the credits you have purchased must be used up within 30 days of purchase or they will be forfeited. At the end of the 30 days, your stored credit card will be charged and your subscription to the API will be auto renewed. You can unsubscribe at any time via the MailboxValidator user area after you have logged in.

Auto recharge

If you have used up your credits before the end of the 30-day cycle, our system will auto recharge your credits to the full amount as per your subscribed plan. Your stored credit card will then be charged and your 30-day cycle begins again.

Upgrades / Downgrades / Unsubscribe

If after using the API for a while and you require more credits per cycle, you can just login to the user area and click Upgrade then select the plan you wish to upgrade to. On the other hand, if you require less credits, you can just click on Downgrade and select which plan you wish to downgrade to. These 2 actions will just be scheduled and will become effective at the end of the current cycle. Before the end of the cycle, you have the option to cancel these pending actions.

As mentioned above, if you want to stop all future charges to your card, you can just click on the Unsubscribe and your subscription will be immediately terminated. This means your API will be disabled with immediate effect.

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