Making HTTP Requests from the ESP32

Fetching data from the internet and parsing a small JSON reply on a microcontroller.

With Wi-Fi joined, the ESP32 can act as a client and pull data from a server the same way a browser does — handy for fetching a value, checking the time, or logging a reading to a cloud service.

#include 
#include 

void loop() {
  if (WiFi.status() == WL_CONNECTED) {
    HTTPClient http;
    http.begin("http://example.local/data");
    int code = http.GET();
    if (code == 200) {
      String body = http.getString();
      Serial.println(body);
    }
    http.end();
  }
  delay(10000);
}

Parsing the reply

Many APIs reply in JSON. A small JSON library lets you pull individual fields out of that text without writing your own parser — worth adding once a reply has more than one or two values you care about.