Email validation API

Confirm your customer's email address at the point of entry with Postcoder email validation.

Validate an email address

Validate email addresses to check whether they're capable of receiving email.

Includes checks on the syntax and the MX record, and detects the presence of a mailbox.

Example code

Request URL

GET |[apikey]/emailaddress/[email-address]

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Optional querystring parameters

formatSets the data format of the response; the default is json unless header of application/xml is detectedxml, jsonjson
identifierSets an identifier like "checkout" or "contactform" to help you group requests within your search history

Response fields

FieldDescriptionExampleReturned by default?
validEmail is valid or not.trueYes
stateMessage about validation. More info belowMailbox Validation TimeoutYes
score0 - 100 Rating for the email, higher is better.50Yes
processtimeInternal time-to-process a request, measured in milliseconds.697Yes
alternativeProvides a "Did you mean?" style correction where possible. For instance, may return an alternative of - if available
warningProvides a warning regarding a reduction in validation quality, usually because the email provider has imposed restrictions on validation.Only reduced validation is available for this domainYes - if available

Possible responses for the 'state' response field

Mailbox Does Not Exist
Mailbox Temporarily Unavailable
Mailbox Validation Timeout
Smtp Connection Timeout
Server Temporary Unavailable
Success (Server is Catch All)
Domain is Well Known DEA
Domain Does Not Exist

Note: DEA stands for Disposable Email Address


  • We recommend you URL encode your request before submitting it
  • Email validations are logged within your account but the actual search term is not stored to protect your users' data
  • Validations will typically complete within a second although may take up to 5 seconds
  • All response fields should be treated as optional
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