Arduino - Gmail

In this guide, we will learn how to set up the Arduino to send an email using your Gmail account. The email will be sent from a Gmail account and can be received by any email account.

Arduino Gmail

Hardware Required

1×Arduino UNO R4 WiFi
1×USB Cable Type-C
1×(Optional) Breadboard
1×(Optional) Jumper Wires
1×(Optional) DC Power Jack
1×(Optional) 9V Power Adapter for Arduino
1×(Recommended) Screw Terminal Block Shield for Arduino Uno
1×(Optional) Transparent Acrylic Enclosure For Arduino Uno

Or you can buy the following sensor kits:

1×DIYables Sensor Kit (30 sensors/displays)
1×DIYables Sensor Kit (18 sensors/displays)
Please note: These are Amazon affiliate links. If you buy the components through these links, We will get a commission at no extra cost to you. We appreciate it.


To use the code, we need a Gmail account and a special password for the app. Here are the important details to remember:

  1. Please make a new Gmail account just for testing, not your usual one, to prevent problems.
  2. The password in the Arduino code is different from your Gmail login password. You must get an "App Password" from your Google Account by following specific steps.

Here are the steps one by one:

Gmail security
  1. Turn on 2-Step Verification (You must activate 2-Step Verification to use app passwords).
  2. Go to the Google App Passwords website and make an app password. You can choose any name for it.
Google App Passwords
  • Press the Create button. You will get a 16-digit password that appears like this:
Gmail App Passwords
  • Keep and save this 16-digit number. You will use it in the Arduino code in the next step.


Google's user interface might change. If you can't find "App Passwords" by following the steps above, search for "How to get Google App Passwords" to find updated instructions.

Arduino Code

/* * Created by * * This example code is in the public domain * * Tutorial page: */ #include <WiFiS3.h> #include <ESP_Mail_Client.h> #define WIFI_SSID "YOUR_WIFI_SSID" // CHANGE IT #define WIFI_PASSWORD "YOUR_WIFI_PASSWORD" // CHANGE IT // the sender email credentials #define SENDER_EMAIL "" // CHANGE IT #define SENDER_PASSWORD "xxxx xxxx xxxx xxxx" // CHANGE IT to your Google App password #define RECIPIENT_EMAIL "" // CHANGE IT #define SMTP_HOST "" #define SMTP_PORT 587 SMTPSession smtp; void setup() { Serial.begin(9600); WiFi.begin(WIFI_SSID, WIFI_PASSWORD); Serial.print("Connecting to Wi-Fi"); while (WiFi.status() != WL_CONNECTED) { Serial.print("."); delay(300); } Serial.println(); Serial.print("Connected with IP: "); Serial.println(WiFi.localIP()); Serial.println(); String subject = "Email Notification from Arduino"; String textMsg = "This is an email sent from Arduino.\n"; textMsg += "Sensor value: "; textMsg += "15"; // OR replace this value read from a sensor gmail_send(subject, textMsg); } void loop() { // YOUR OTHER CODE HERE } void gmail_send(String subject, String textMsg) { // set the network reconnection option MailClient.networkReconnect(true); smtp.debug(1); smtp.callback(smtpCallback); Session_Config config; // set the session config config.server.host_name = SMTP_HOST; config.server.port = SMTP_PORT; = SENDER_EMAIL; config.login.password = SENDER_PASSWORD; config.login.user_domain = F(""); config.time.ntp_server = F(","); config.time.gmt_offset = 3; config.time.day_light_offset = 0; // declare the message class SMTP_Message message; // set the message headers = F("Arduino"); = SENDER_EMAIL; message.subject = subject; message.addRecipient(F("To Whom It May Concern"), RECIPIENT_EMAIL); message.text.content = textMsg; message.text.transfer_encoding = "base64"; message.text.charSet = F("utf-8"); message.priority = esp_mail_smtp_priority::esp_mail_smtp_priority_low; // set the custom message header message.addHeader(F("Message-ID: <>")); // connect to the server if (!smtp.connect(&config)) { Serial.println("Connection error: "); Serial.print("- Status Code: "); Serial.println(smtp.statusCode()); Serial.print("- Error Code: "); Serial.println(smtp.errorCode()); Serial.print("- Reason: "); Serial.println(smtp.errorReason().c_str()); return; } if (!smtp.isLoggedIn()) { Serial.println("Not yet logged in."); } else { if (smtp.isAuthenticated()) Serial.println("Successfully logged in."); else Serial.println("Connected with no Auth."); } // start sending Email and close the session if (!MailClient.sendMail(&smtp, &message)) { Serial.println("Connection error: "); Serial.print("- Status Code: "); Serial.println(smtp.statusCode()); Serial.print("- Error Code: "); Serial.println(smtp.errorCode()); Serial.print("- Reason: "); Serial.println(smtp.errorReason().c_str()); } } // callback function to get the Email sending status void smtpCallback(SMTP_Status status) { // print the current status Serial.println(; // print the sending result if (status.success()) { for (size_t i = 0; i < smtp.sendingResult.size(); i++) { // get the result item SMTP_Result result = smtp.sendingResult.getItem(i); Serial.print("Status: "); if (result.completed) Serial.println("success"); else Serial.println("failed"); Serial.print("Recipient: "); Serial.println(result.recipients.c_str()); Serial.print("Subject: "); Serial.println(result.subject.c_str()); } Serial.println("----------------\n"); // free the memory smtp.sendingResult.clear(); } }

Quick Steps

  • If this is the first time you use Arduino Uno R4, see how to setup environment for Arduino Uno R4 on Arduino IDE.
  • Connect the Arduino board to your PC using a USB cable.
  • Open the Arduino IDE on your PC.
  • Select the right Arduino board (Arduino Uno R4 WiFi) and COM port.
  • Open the Library Manager by clicking on the Library Manager icon on the left side of the Arduino IDE.
  • Search for ESP Mail Client and find the ESP Mail Client by Mobizt.
  • Click the Install button to install the ESP Mail Client library.
Arduino ESP Mail Client library
  • Copy the code above and open it in the Arduino IDE.
  • Update your WiFi details by replacing WIFI_SSID and WIFI_PASSWORD with your WiFi network's SSID and password.
  • Edit your email details in the code by entering your email and password in SENDER_EMAIL and SENDER_PASSWORD.
  • Change the email address for receiving messages to your email by updating RECIPIENT_EMAIL. Note: the recipient email may be the same as the sender's email.


  • The email of the sender must be a Gmail account.
  • The password for the sender is the App password you received in the previous step.
  • The recipient's email can be of any type.
  • Click the Upload button in Arduino IDE to send code to Arduino.
  • Open the Serial Monitor.
  • Look at the result on Serial Monitor.
#### Message sent successfully > C: message sent successfully ---------------- Message sent success: 1 Message sent failed: 0 ---------------- Message No: 1 Status: success Date/Time: May 27, 2024 04:42:50 Recipient: Subject: Email Notification from Arduino ----------------
Autoscroll Show timestamp
Clear output
9600 baud  
  • Check the email inbox of the person you sent the email to. You will receive an email like the following:
Arduino sends email

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