Learn how to use webhooks.
Content-Type: application/vnd.api+json header.
Webhooks have 6 events to listen for your purposes:
Contract.created: fires when a contract is created.Contract.sent: fires for every recipient to whom a contract was sent.Contract.seen: fires every time a recipient opens a contract.Contract.approved: fires every time a recipient approves a contract.Contract.signed: fires every time a recipient signs a contract.Contract.fully_signed: fires once when all the recipients have signed a contract.