Create contact

Creates a contact. first_name, last_name, email and gender are required. Names are title-cased (names already carrying capitals, like McDonald or O’Brien, are preserved as sent), email is lower-cased, and ni_number must match the UK format e.g. QQ123456C.

Your organisation is derived from your API key. There is no field for naming an organisation or a CRM, and any unrecognised field in the body returns 400 rather than being ignored — so a misunderstanding surfaces immediately instead of silently doing nothing.