Parameter	Mandatory	Description	Examples	More Info
API	Yes	The API area	clientcontacts.json
General	Yes	Parameters described in overview	user=user&password=user	Structure of an API call
Action	Yes	The action to perform	action=opt_in
Identifier	Yes	Contact ID or UUID	clientcontact=8589

Example request:

http://&lt;SERVER&gt;/jsonapi/clients.json?user=user&password=user&version=4&action=opt_in&clientcontact=8589

Example response:

{
  "responsecode": 1,
  "responsestatus": "OK",
  "errorcode": 0,
  "errormessage": "",
  "responsemessage": "Client contact(s) opt in changed. ",
  "warningmessage": "",
  "success": true
}