curl --request POST \
--url https://api.telli.com/v1/add-contact \
--header 'Authorization: <api-key>' \
--header 'Content-Type: application/json' \
--data '{
"external_contact_id": "<string>",
"external_url": "<string>",
"salutation": "<string>",
"first_name": "<string>",
"last_name": "<string>",
"phone_number": "<string>",
"email": "jsmith@example.com",
"contact_details": {},
"timezone": "<string>"
}'