Contacts: Validate an Email Address

Use this action to check that an email address is formatted correctly, free of common spelling mistakes, and verified by a mail server.

Use case

This action is helpful when sending a survey or update to a large list on contacts to avoid getting email bounces.

This action can be used effectively as a subprocess if you have emails stored in a spreadsheet or a data table by using the Excel: Start Process for Each Row or Tables: Start Workflow for Each Row actions

How to configure this action

Fields for this action

  • Email address

    • The email address to validate, as text or in {field-name} format
  • Mailbox verification

    • Provides option to verify address with server. Select True or False from the drop down.
      • Select True to attempt to verify that the address exists by contacting the mail server.
      • Leave blank or select False to skip contacting the mail server.
    • ✅   Heads-up: Mailbox verification can significantly increase the time it takes for this action to complete.
  • Output Field Prefix

    • To help keep output fields organized, choose an output field prefix to add to the beginning of each output field name as this action may output more than one field.
    • The step’s name is used as the prefix by default.

What will this output?

This action may generate multiple fields. To help keep output fields organized, the prefix above will be added to the beginning of each of the output field names, separated by two dashes. Each field will result as:{{output-field-prefix--output-field}}. Learn more

Output fields for this action

  • Address

    • The Email address that was used
  • Did you mean

    • Provides a suggested correction to the email address when appropriate
  • Is disposable address

    • Returns true if the address is disposable
  • Is role address

    • Returns true if the address is for a team, such as sales@ or product@
  • Is valid

    • Returns true if an email address passes grammar and formatting checks and a valid SMTP server is present for the address. A valid address may still be a disposable or role address.
  • Mailbox verification

    • Returns true if the email is valid
    • Returns false if the email was invalid
    • Returns unknown if the SMTP request could not be completed or the recipient’s mail provider does not support mailbox verification.
  • Parts - display name

    • Provides a display name if one is attached to the address, blank if none
  • Parts - domain

    • Provides the domain of the address
  • Parts - local part

    • Provides the section of the address before the domain (e.g., sales for
  • Reason invalid

    • Provides the reason the email was marked as invalid, when invalid. These are returned as 3 digit status codes like 2.0.0, 2.1.5, or 4.7.1. When you validate an email address, the mail server itself responds with a specific status code. The same status code may mean different things depending on the mail server.

    • For a summary of different status code types and what they may mean, see List of possible status codes

Get help with a problem or question

If something’s not working as expected, or you’re looking for suggestions, check through the options below.

List of possible “reason invalid” status codes

There are 5 categories of status codes:

  • 1XX: Informational code, for example your request was received, but the server was unable or refused to validate it.
  • 2XX: Success code, for the request was valid and accepted.
  • 3XX: Redirection code, for example your request could not be validated until more steps are taken.
  • 4XX: Clients error code, for example your request may be valid, but there is a syntax issue or other issue that can’t be resolved.
  • 5XX: Server error code, for example your request was valid, but the mail server encountered an internal error and failed to process it.
1XX Informational status codes
Code Description
101 Unable to connect to server
111 Connection refused, or blocked by configuration or firewall
2XX Success status codes

The 2XX codes indicate the request was received, valid, and accepted.

Code Description
200 System status message
214 A specific response to the HELP command
220 The server is ready
221 The mail server is closing
250 Requested mail action okay completed
251 Mail will be forwarded because the user was not found
252 Cannot verify the user, but it will try to deliver the message anyway
3XX Redirection status code
Code Description
354 Start adding mail input
4XX Persistent transient failure status Code

For more 4XX status codes, mail servers will attempt to retry after a delay. Servers may retry for up to 2 days before reporting another status code.

Code Description
420 Timeout connection problem
421 Service is unavailable due to a connection problem
422 The recipient’s mailbox has exceeded its storage limit
431 Not enough space on the disk
432 Recipient’s incoming mail queue has been stopped
441 The recipient’s server is not responding
442 The connection was dropped during the transmission
446 The maximum hop count was exceeded for the message
447 Message timed out because of issues concerning the incoming server
449 Routing error
450 User’s mailbox is unavailable
451 Aborted – Local error in processing
452 Too many emails sent or too many recipients
471 An error of your mail server
5XX Server permanent error codes

The 5XX status codes mean the mail was officially undeliverable.

Code Description
500 Syntax error
501 Syntax error in parameters or arguments
503 Bad sequence of commands, or requires authentication
504 Command parameter is not implemented
510 / 511 Bad email address
512 Host server for the recipient’s domain name cannot be found in DNS
513 Address type is incorrect
523 Size of your mail exceeds the server limits
530 Authentication problem
541 The recipient address rejected your message
550 Non-existent email address
551 User not local or invalid address – relay denied
552 Exceeded storage allocation
553 Mailbox name invalid
554 Transaction has failed

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