Double-Optin Process through API form external preference center

Hi, does anyone can share experiance and best practice on how to setup the double-optin process with Marketo using the API.
We are working with our own preference-center, customer submit a subscription-from from our preference-center, how to run this through
Marketo, to send the opt-in email - and keep the lead-record(person) in a status "waiting for optin" until a contact has confirmed.