The challenge I have is that, while the documentation and other columns accept countryShortName, but the error message I keep getting is specifically for column_id:"phone_mknjb3xj":

"column_value":"{\\"phone\\"=>\\"(919) 929-0202\\", \\"countryShortName\\"=>\\"US\\"}" "message":"invalid value, please check our API documentation for the correct data structure for this column." "column_name":"Mobile Phone"

tl;dr – Format your JSON correctly.

monday’s own Ask AI/ “Need Help?” button on this page says:

The error message you’re seeing:

"invalid value, please check our API documentation for the correct data structure for this column. https://developer.monday.com/api-reference/docs/change-column-values"

...

"error_data":{"column_type":"phone","column_id":"phone_mknjb3xj","column_value":"{\\"phone\\"=>\\"(919) 929-0202\\", \\"countryShortName\\"=>\\"US\\"}"}

means that the value you’re sending for the phone column is not in the correct format expected by the monday.com API.

Key issues:

• The value you’re sending uses Ruby-style hash rockets (=>) instead of JSON colons (:).


• The phone number format may also be problematic.

Correct format:

The API expects a JSON string with colons, like this:

{"phone": "(919) 929-0202", "countryShortName": "US"}

But when sending this in a GraphQL mutation, it should be a string, for example:

mutation {

  change_multiple_column_values(

    item_id: 9876543210,

    board_id: 1234567890,

    column_values: "{\\"phone_mknjb3xj\\": {\\"phone\\": \\"(919) 929-0202\\", \\"countryShortName\\": \\"US\\"}}"

  ) {

    id

  }

}

Or, for item creation:

mutation {

  create_item(

    board_id: 1234567890,

    group_id: "group_one",

    item_name: "New contact",

    column_values: "{\\"phone_mknjb3xj\\": {\\"phone\\": \\"(919) 929-0202\\", \\"countryShortName\\": \\"US\\"}}"

  ) {

    id

  }

}

Important:

• Make sure you use colons (:) in your JSON, not hash rockets (=>).


• The phone number should be in a valid format, ideally including the country code (e.g., +19199290202). The API uses the Google Phone Library for validation, so the number must be valid for the given country code.


• Double-check that your JSON is properly escaped if you’re building it in code.

Reference:

See the official documentation for the correct phone column format and examples: Update the phone column and Changing column values.

Summary:

Replace {"phone"=>"(919) 929-0202", "countryShortName"=>"US"} with {"phone": "(919) 929-0202", "countryShortName": "US"} (as a JSON string), and ensure the phone number is valid for the US. This should resolve the error.