How Does Arduino Send Data to Web Server?


Angela Bailey

In this tutorial, we will explore how Arduino can send data to a web server. Arduino is an open-source electronics platform that allows you to create interactive projects. By connecting Arduino to the internet, you can easily send data from your Arduino board to a web server for further analysis or storage.


Before getting started, you will need the following:

  • An Arduino board (such as Arduino Uno or Arduino Mega)
  • An Ethernet shield or Wi-Fi module
  • A computer with the Arduino IDE installed
  • A web server with PHP support (optional)

Step 1: Connect Arduino to the Internet

The first step is to connect your Arduino board to the internet. If you are using an Ethernet shield, simply plug it into the Arduino board and connect it to your router using an Ethernet cable. If you are using a Wi-Fi module, follow the manufacturer’s instructions to connect it to your local Wi-Fi network.

Step 2: Install Required Libraries

To enable communication between Arduino and the web server, we need to install some libraries in the Arduino IDE. Open the IDE and go to Sketch > Include Library > Manage Libraries. Search for “Ethernet” or “Wi-Fi” depending on your setup and install the appropriate library.

Step 3: Set up HTTP Connection

To send data to a web server, we will use the Hypertext Transfer Protocol (HTTP). We need to create an HTTP connection between our Arduino and the server. Here’s an example code snippet:

#include <Ethernet.h>

byte mac[] = {0xDE, 0xAD, 0xBE, 0xEF, 0xFE, 0xED};
IPAddress server(192, 168, 1, 100);
EthernetClient client;

void setup() {

void loop() {
  if (client.connect(server, 80)) {
    client.println("GET /data.php?value=42 HTTP/1.1");
    client.println("Connection: close");

This code establishes a TCP/IP connection with the web server and sends an HTTP GET request with a parameter “value” set to “42”. Modify the server IP address and the request URL to match your setup.

Step 4: Process Data on the Server

On the web server side, you need to have a script that can receive and process the data sent by Arduino. Here’s a simple example using PHP:

$value = $_GET['value'];
// Process the data here
// For example, store it in a database or perform some calculations

This PHP script retrieves the value sent by Arduino using the “value” parameter in the URL. You can then process this data in any way you like.

Step 5: Test and Monitor

Upload the Arduino code to your board and make sure it is connected to your network. Open a serial monitor in the Arduino IDE to monitor any debug messages. Check if the data is being sent successfully by looking at the server response or monitoring your database.

Troubleshooting Tips:

  • If you are using Wi-Fi and facing connection issues, double-check your Wi-Fi credentials and network settings.
  • Ensure that your web server is running and can handle incoming requests.
  • If you encounter any errors, refer to the documentation of the libraries you are using or search online forums for solutions.

That’s it! You have learned how Arduino can send data to a web server.

Now you can explore various applications such as remote monitoring, data logging, or controlling devices over the internet. Have fun experimenting!

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