There is no public API yet. What there is: your reservations in and out over CSV, calendar files for the stays themselves, Peppol for the invoices, and an export on request whenever you want the lot.
bookings-2026-07.csv
reference,arrival,departure,room,nights,guests,status,total
B-2026-0841,2026-07-28,2026-07-30,109,2,2,checked_in,289.00
B-2026-0842,2026-07-28,2026-07-29,204,1,1,confirmed,144.50
B-2026-0843,2026-07-29,2026-08-02,111,4,2,option,612.00