Outcall names which half of a booking moves, and here it is always the therapist, who travels to the address you are already sleeping at rather than asking you to cross a dark city.
At two in the morning the question of who travels stops being a detail and becomes the whole arrangement. Outcall settles it in one direction. The therapist leaves from wherever she is, makes her way to the address written in the booking thread, and knocks. You stay where you are, in the room you already have a key to, with the door you already know how to lock.
Forty-five therapists work from this roster and the house keeps no premises at all. No studio, no flat kept for the purpose, no address a visitor could be given at four in the morning. That absence is the point rather than a gap. A journey across an unfamiliar city in the small hours, with a phone at nine percent and a return trip still ahead, is the part of a late booking most likely to go wrong, and outcall deletes it entirely.
Central Amsterdam runs on a single figure at every hour of the night: forty to sixty minutes from the moment a booking is confirmed until she is at the door, the same in every central neighbourhood, at eleven and at half past four alike. Schiphol and the hotels around it sit outside that figure and are arranged separately, with the journey time agreed with you before anything is fixed. Nothing beyond Amsterdam and those airport hotels is reached, whatever the hour.
Very little, and all of it can be typed in under a minute. An exact address with a floor and a room or apartment number. A phone left face up and charged, because a silent phone at three in the morning is the one thing that can undo an otherwise settled booking. A line about the entrance if the building locks its lift or its street door after a certain hour, which night entry covers in full. The booking page lists what a first message should carry, and no part of the fee changes because of the hour on the clock.
Two lines settle it: where the room is, and what time you want someone at the door. The answer comes back with a name, an arrival window and the whole figure, whatever the clock says.