Before the COVID-19 pandemic, pulse oximeters were commonly used in clinics, hospitals, medical centers, and homes of individuals requiring a prescription. As a result of the health crisis caused by COVID-19, their use has been normalized and they can now be found in the first aid kit of many homes along with the thermometer. This article shows the design and experimental implementation of a pulse oximeter using an ESP32 microcontroller that allows through its Bluetooth and WiFi modules to perform an IoT (Internet of Things) application in conjunction with the online platform ThingSpeak and the Android application Blynk, generating remote and real-time monitoring of the information generated by a sensor that can measure blood oxygen concentration and heart rate reference MAX30102.