Quinta da Regaleira: book on your phone, your plate opens the gate.

Quinta da Regaleira is one of Sintra's most visited monuments — and arriving by car is a problem: narrow roads, long queues, especially for those who just need to pass through, like residents and partner-hotel guests.

The idea: instead of everyone waiting in line, approved vehicles book their visit on a phone and pass through a dedicated lane, recognised automatically by their plate.

Managing physical traffic isn't a software-only problem. An app with bookings isn't enough — the system has to act in the real world: recognise the right car at the entrance and let it through at the right moment. A booking in the cloud is worthless if it doesn't turn into a green light on the road. Closing that loop, between the screen and the gate, was the hard part.

We built the whole thing — the apps, the backend and the bridge to the hardware.

A mobile app (React Native) where residents and guests register their vehicle and book a visit; a backoffice (React) where the monument's team manages bookings, vehicles and passages, with a schedule view.

A backend (NestJS, GraphQL) holds vehicles, bookings, passages and one-time plates, and notifies people by push.

At the entrance, cameras read the plates with computer vision — detection and OCR. When a recognised, booked plate arrives, the system talks directly to the traffic lights through the industrial controller (PLC) and opens the dedicated lane. The booking in the app becomes a green light on the road.

Today approved vehicles skip the queue: they book in the app, reach the gate, the camera reads the plate, the light turns green. The monument manages its flow instead of suffering it.

If your problem lives partly in the physical world — a gate, a sensor, a machine — software alone isn't enough. The value is in closing the loop between the screen and reality. That's what we did.