Search Author API using an author custom field

You can search authors using any ANS field, standard or custom with Author API. 

Use Author API v1 and pass in the search value in the q parameter: https://api.yourorganization.arcpublishing.com/author/v1/author-service/?q={}

Example:

https://api.{{org}}.arcpublishing.com/author/v1/author-service/?q={
  "author_type": {
    "$in": ["FieldName", "FieldValue"]
  }
}

Arc XP Authors API