This is a very simple webserver that runs on a ESP32 that takes a reading from a door sensor and provides a binary open/close metric. As checked in this repo it's at http://ip-of-your-esp32:9000
Credit to ESP32.io whom I learned how to read the door sensor from: https://esp32io.com/tutorials/esp32-door-sensor
Credit to codetiger as I learned how to write a simple web exporter from them: https://github.com/codetiger/PowerConsumptionMonitor-ESP32/blob/main/PowerConsumptionMonitor/PowerConsumptionMonitor.ino