curl --request GET \
  --url https://api.zenskar.com/contacts/{contact_id} \
  --header 'organisation: <api-key>' \
  --header 'x-api-key: <api-key>'

{
  "id": "3c90c3cc-0d44-4b50-8888-8dd25736052a",
  "customer": "3c90c3cc-0d44-4b50-8888-8dd25736052a",
  "email": "<string>",
  "first_name": "<string>",
  "last_name": "<string>",
  "send_contract": false,
  "send_invoice": true
}