Connecting InboxBill to FreeAgent takes about 5 minutes and requires only clicking 'Authorise' in the FreeAgent OAuth flow. Here's the exact process.
InboxBill imports your existing FreeAgent contacts so it can match incoming invoices to known suppliers. When you approve an invoice in InboxBill, it creates a bill in FreeAgent using the FreeAgent API — this appears in your FreeAgent purchases list immediately.