Arduino Nano ESP32 - HTTP Request

This tutorial provides instructions on how to use Arduino Nano ESP32 to make HTTP request to web server, API, or Web service. In detail, You will learn:

Arduino Nano ESP32 web client

Hardware Preparation

1×Arduino Nano ESP32
1×USB Cable Type-C
1×Breadboard
1×Jumper Wires
1×(Optional) DC Power Jack
1×(Recommended) Screw Terminal Adapter for Arduino Nano

Or you can buy the following sensor kit:

1×DIYables Sensor Kit 30 types, 69 units
Disclosure: Some of the links provided in this section are Amazon affiliate links. We may receive a commission for any purchases made through these links at no additional cost to you. We appreciate your support.

Basic Concepts of Web Client and Web Server

There are some basic concepts of web such as: web address (URL), hostname, pathname, query string, HTTP Request... You can learn detailed about them in HTTP tutorial

How to Make an HTTP Request

  • Include libraries
#include <WiFi.h> #include <HTTPClient.h>
  • Declare WiFi SSID and password
const char WIFI_SSID[] = "YOUR_WIFI_SSID"; // CHANGE IT const char WIFI_PASSWORD[] = "YOUR_WIFI_PASSWORD"; // CHANGE IT
  • Declare hostname, pathname, query string
String HOST_NAME = "http://YOUR_DOMAIN.com"; // CHANGE IT String PATH_NAME = "/products/arduino"; // CHANGE IT //String PATH_NAME = "/products/arduino.php"; // CHANGE IT String queryString = "temperature=26&humidity=70"; // OPTIONAL
  • Declare a HTTP client object
HTTPClient http;
  • If connected to server, and send HTTP request. For example, HTTP GET
http.begin(HOST_NAME + PATH_NAME); //HTTP int httpCode = http.GET();
  • Read the response data from web server
// httpCode will be negative on error if (httpCode > 0) { // file found at server if (httpCode == HTTP_CODE_OK) { String payload = http.getString(); Serial.println(payload); } else { // HTTP header has been send and Server response header has been handled Serial.printf("[HTTP] GET... code: %d\n", httpCode); } } else { Serial.printf("[HTTP] GET... failed, error: %s\n", http.errorToString(httpCode).c_str()); } http.end();

How to include data into HTTP request

We can send data to the web server by including data into HTTP request. The data format depends on HTTP request method:

  • For HTTP GET request
    • Data can be only sent in query string on the pathname.
  • HTTP POST request
    • Data can be sent NOT ONLY in query string format BUT ALSO any other format such as Json, XML, image ...
    • Data is put in HTTP request body.

    Let's learn how to send data in query string format for both HTTP GET and POST

    • Create a query string
    int temp = // from sensor int humi = // from sensor String queryString = String("temperature=") + String(temp) + String("&humidity=") + String(humi);
    • HTTP GET: add query string to pathname
    http.begin(HOST_NAME + PATH_NAME + "?" + queryString); http.addHeader("Content-Type", "application/x-www-form-urlencoded"); int httpCode = http.GET();
    • HTTP POST: put query string in HTTP body
    http.begin(HOST_NAME + PATH_NAME); http.addHeader("Content-Type", "application/x-www-form-urlencoded"); int httpCode = http.POST(queryString);
    • For both GET and POST, read the response data from web server
    // httpCode will be negative on error if (httpCode > 0) { // file found at server if (httpCode == HTTP_CODE_OK) { String payload = http.getString(); Serial.println(payload); } else { // HTTP header has been send and Server response header has been handled Serial.printf("[HTTP] GET/POST... code: %d\n", httpCode); } } else { Serial.printf("[HTTP] GET/POST... failed, error: %s\n", http.errorToString(httpCode).c_str()); } http.end();

Complete Arduino Nano ESP32 Code for Making HTTP Request

The blow is the complete Arduino Nano ESP32 code for making HTTP GET/POST request

/* * This Arduino Nano ESP32 code was developed by newbiely.com * * This Arduino Nano ESP32 code is made available for public use without any restriction * * For comprehensive instructions and wiring diagrams, please visit: * https://newbiely.com/tutorials/arduino-nano-esp32/arduino-nano-esp32-http-request */ #include <WiFi.h> #include <HTTPClient.h> const char WIFI_SSID[] = "YOUR_WIFI_SSID"; // CHANGE IT // CHANGE IT const char WIFI_PASSWORD[] = "YOUR_WIFI_PASSWORD"; // CHANGE IT String HOST_NAME = "http://YOUR_DOMAIN.com"; // CHANGE IT String HOST_NAME = "http://YOUR_DOMAIN.com"; // CHANGE IT //String PATH_NAME = "/products/arduino.php"; // CHANGE IT void setup() { Serial.begin(9600); WiFi.begin(WIFI_SSID, WIFI_PASSWORD); Serial.println("Connecting"); while(WiFi.status() != WL_CONNECTED) { delay(500); Serial.print("."); } Serial.println(""); Serial.print("Connected to WiFi network with IP Address: "); Serial.println(WiFi.localIP()); HTTPClient http; http.begin(HOST_NAME + PATH_NAME); //HTTP int httpCode = http.GET(); // httpCode will be negative on error if(httpCode > 0) { // file found at server if(httpCode == HTTP_CODE_OK) { String payload = http.getString(); Serial.println(payload); } else { // HTTP header has been send and Server response header has been handled Serial.printf("[HTTP] GET... code: %d\n", httpCode); } } else { Serial.printf("[HTTP] GET... failed, error: %s\n", http.errorToString(httpCode).c_str()); } http.end(); } void loop() { }

Complete Arduino Nano ESP32 Code for Making HTTP GET Request with data

/* * This Arduino Nano ESP32 code was developed by newbiely.com * * This Arduino Nano ESP32 code is made available for public use without any restriction * * For comprehensive instructions and wiring diagrams, please visit: * https://newbiely.com/tutorials/arduino-nano-esp32/arduino-nano-esp32-http-request */ #include <WiFi.h> #include <HTTPClient.h> const char WIFI_SSID[] = "YOUR_WIFI_SSID"; // CHANGE IT const char WIFI_PASSWORD[] = "YOUR_WIFI_PASSWORD"; // CHANGE IT String HOST_NAME = "http://YOUR_DOMAIN.com"; // CHANGE IT String PATH_NAME = "/products/arduino"; // CHANGE IT //String PATH_NAME = "/products/arduino.php"; // CHANGE IT String queryString = "temperature=26&humidity=70"; void setup() { Serial.begin(9600); WiFi.begin(WIFI_SSID, WIFI_PASSWORD); Serial.println("Connecting"); while (WiFi.status() != WL_CONNECTED) { delay(500); Serial.print("."); } Serial.println(""); Serial.print("Connected to WiFi network with IP Address: "); Serial.println(WiFi.localIP()); HTTPClient http; http.begin(HOST_NAME + PATH_NAME + "?" + queryString); http.addHeader("Content-Type", "application/x-www-form-urlencoded"); int httpCode = http.GET(); // httpCode will be negative on error if (httpCode > 0) { // file found at server if (httpCode == HTTP_CODE_OK) { String payload = http.getString(); Serial.println(payload); } else { // HTTP header has been send and Server response header has been handled Serial.printf("[HTTP] GET... code: %d\n", httpCode); } } else { Serial.printf("[HTTP] GET... failed, error: %s\n", http.errorToString(httpCode).c_str()); } http.end(); } void loop() { }

Complete Arduino Nano ESP32 Code for Making HTTP POST Request with data

/* * This Arduino Nano ESP32 code was developed by newbiely.com * * This Arduino Nano ESP32 code is made available for public use without any restriction * * For comprehensive instructions and wiring diagrams, please visit: * https://newbiely.com/tutorials/arduino-nano-esp32/arduino-nano-esp32-http-request */ #include <WiFi.h> #include <HTTPClient.h> const char WIFI_SSID[] = "YOUR_WIFI_SSID"; // CHANGE IT const char WIFI_PASSWORD[] = "YOUR_WIFI_PASSWORD"; // CHANGE IT String HOST_NAME = "http://YOUR_DOMAIN.com"; // CHANGE IT String PATH_NAME = "/products/arduino"; // CHANGE IT //String PATH_NAME = "/products/arduino.php"; // CHANGE IT String queryString = "temperature=26&humidity=70"; void setup() { Serial.begin(9600); WiFi.begin(WIFI_SSID, WIFI_PASSWORD); Serial.println("Connecting"); while (WiFi.status() != WL_CONNECTED) { delay(500); Serial.print("."); } Serial.println(""); Serial.print("Connected to WiFi network with IP Address: "); Serial.println(WiFi.localIP()); HTTPClient http; http.begin(HOST_NAME + PATH_NAME); http.addHeader("Content-Type", "application/x-www-form-urlencoded"); int httpCode = http.POST(queryString); // httpCode will be negative on error if (httpCode > 0) { // file found at server if (httpCode == HTTP_CODE_OK) { String payload = http.getString(); Serial.println(payload); } else { // HTTP header has been send and Server response header has been handled Serial.printf("[HTTP] POST... code: %d\n", httpCode); } } else { Serial.printf("[HTTP] POST... failed, error: %s\n", http.errorToString(httpCode).c_str()); } http.end(); } void loop() { }