Arduino Nano ESP32 - Gmail

This guide will show you how to configure the Arduino Nano ESP32 to send an email through your Gmail account. You can send emails from your Gmail to any other email account.

Arduino Nano ESP32 Gmail

Hardware Preparation

1×Arduino Nano ESP32
1×USB Cable Type-C
1×(Recommended) Screw Terminal Adapter for Arduino Nano

Or you can buy the following sensor kits:

1×DIYables Sensor Kit (30 sensors/displays)
1×DIYables Sensor Kit (18 sensors/displays)
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.


To use the code, you need a Gmail account and a special app password. Here are the key points to remember:

  1. Create a new Gmail account specifically for testing, not your regular one, to avoid any issues.
  2. The password used in the Arduino Nano ESP32 code is not the same as your Gmail password. You need to obtain an "App Password" from your Google Account by following certain steps.

Here are the steps one by one:

Gmail security
  • Activate 2-Step Verification (It is necessary to enable 2-Step Verification before using app passwords).
  • Visit the Google App Passwords website and create an app password. You can name it whatever you like.
Google App Passwords
  • Click the Create button. A 16-digit password will appear as follows:
Gmail App Passwords
  • Save this 16-digit number. You will need it for the Arduino Nano ESP32 code in the next step.


Google's layout may be updated. If you can't locate "App Passwords" using the above steps, search for "How to get Google App Passwords" to get the latest instructions.

Arduino Nano ESP32 Code

/* * This Arduino Nano ESP32 code was developed by * * This Arduino Nano ESP32 code is made available for public use without any restriction * * For comprehensive instructions and wiring diagrams, please visit: * */ #include <WiFi.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 ESP32"; String textMsg = "This is an email sent from ESP32.\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("ESP32"); = 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.printf("Connection error, Status Code: %d, Error Code: %d, Reason: %s\n", smtp.statusCode(), smtp.errorCode(), 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.printf("Error, Status Code: %d, Error Code: %d, Reason: %s\n", smtp.statusCode(), smtp.errorCode(), 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()) { Serial.println("----------------"); Serial.printf("Message sent success: %d\n", status.completedCount()); Serial.printf("Message sent failed: %d\n", status.failedCount()); Serial.println("----------------\n"); for (size_t i = 0; i < smtp.sendingResult.size(); i++) { // get the result item SMTP_Result result = smtp.sendingResult.getItem(i); Serial.printf("Message No: %d\n", i + 1); Serial.printf("Status: %s\n", result.completed ? "success" : "failed"); Serial.printf("Date/Time: %s\n", MailClient.Time.getDateTimeString(result.timestamp, "%B %d, %Y %H:%M:%S").c_str()); Serial.printf("Recipient: %s\n", result.recipients.c_str()); Serial.printf("Subject: %s\n", result.subject.c_str()); } Serial.println("----------------\n"); // free the memory smtp.sendingResult.clear(); } }

Detailed Instructions

To get started with Arduino Nano ESP32, follow these steps:

  • If you are new to Arduino Nano ESP32, refer to the tutorial on how to set up the environment for Arduino Nano ESP32 in the Arduino IDE.
  • Connect the Arduino Nano ESP32 board to your computer using a USB cable.
  • Launch the Arduino IDE on your computer.
  • Select the Arduino Nano ESP32 board and its corresponding COM port.
  • Open the Library Manager by clicking Library Manager icon on the left in the Arduino IDE.
  • Search for ESP Mail Client and find the library by Mobizt.
  • Click Install button to install the ESP Mail Client library.
Arduino Nano ESP32 ESP Mail Client library
  • Copy the above code and paste it into the Arduino IDE.
  • Enter your WiFi network name and password where it says WIFI_SID and WIFI_PASSWORD.
  • Put your email and password into the SENDER_EMAIL and SENDER_PASSWORD fields in the code.
  • Update RECIPIENT_EMAIL to the email address where you want to receive messages. This can be your own email if necessary.


  • The sender's email should be a Gmail account.
  • Use the App password given to you before as the password for the sender.
  • The email of the person receiving it can be any kind of email.
  • Press the Upload button in Arduino IDE to transfer code to the Arduino Nano ESP32.
  • Open the Serial Monitor.
  • Check the output on the 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 Nano ESP32 ----------------
Autoscroll Show timestamp
Clear output
9600 baud  
  • Check out the email inbox of receiver. You will find an email similar to this:
Arduino Nano ESP32 sends email

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