Learn how to send emails with the ESP32 using an SMTP Server. We’ll show you how to send a simple email with HTML or raw text and how to send attachments like images and files (.txt). The ESP32 board will be programmed using Arduino IDE.
In this tutorial, we cover the following topics:
We have a similar tutorial for the ESP8266 board: ESP8266 NodeMCU Send Emails using an SMTP Server: HTML, Text, and Attachments (Arduino)
Introducing SMTP Servers
SMTP means Simple Mail Transfer Protocol and it is an internet standard for email transmission. To send emails using an ESP32, you need to connect it to an SMTP Server.
ESP Mail Client Library
To send emails with the ESP32, we’ll use the ESP-Mail-Client library. This library allows the ESP32 to send and receive emails with or without attachments via SMTP and IMAP servers.
In this tutorial, we’ll use SMTP to send an email with and without attachments. As an example, we’ll send an image (.png) and a text (.txt) file. The files sent via email can be saved in the ESP32 Filesystem (SPIFFS) or a microSD card (not covered in this tutorial).
Installing the ESP-Mail-Client Library
Before proceeding with this tutorial, you need to install the ESP-Mail-Client library. This library is not available to install through the Arduino IDE Library Manager. Follow the next steps to install the library:
- Click here to download ESP-Mail-Client library .zip folder.
- In your Arduino IDE, go to Sketch > Include Library > Add .ZIP Library.
- Select the .zip file you’ve just downloaded.
Then, if you go to File > Examples > ESP-Mail-Client, you’ll find several examples that you can try. You can also access the examples in the library GitHub page—here.
If you’re using the ESP32 with VS Code + PlatformIO, you should copy the following to your platformio.ini file to include the library.
lib_deps = mobizt/ESP Mail Client @ ^1.3.0Sender Email (New Account)
We recommend creating a new email account to send the emails to your main personal email address. Do not use your main personal email to send emails via ESP32. If something goes wrong in your code or if by mistake you make too many requests, you can be banned or have your account temporarily disabled.
We’ll use a newly created Gmail.com account to send the emails, but you can use any other email provider. The receiver email can be your personal email without any problem.
Create a Sender Email Account
Create a new email account for sending emails with the ESP32. If you want to use a Gmail account, go to this link to create a new one.
Create an App Password
You need to create an app password so that the ESP32 is able to send emails using your Gmail account. An App Password is a 16-digit passcode that gives a less secure app or device permission to access your Google Account. Learn more about sign-in with app passwords here.
An app password can only be used with accounts that have 2-step verification turned on.
- Open your Google Account.
- In the navigation panel, select Security.
- Under “Signing in to Google,” select 2-Step Verification > Get started.
- Follow the on-screen steps.
After enabling 2-step verification, you can create an app password.
- Open your Google Account.
- In the navigation panel, select Security.
- Under “Signing in to Google,” select App Passwords.
- In the Select app field, choose mail. For the device, select Other and give it a name, for example ESP32. Then, click on Generate. It will pop-up a window with a password that you’ll use with the ESP32 or ESP8266 to send emails. Save that password (even though it says you won’t need to remember it) because you’ll need it later.
Now, you should have an app password that you’ll use on the ESP32 code to send the emails.
If you’re using another email provider, check what you need to do to allow less secure apps. You should be able to find the instructions with a quick google search “your_email_provider + allow less secure apps”.
Gmail SMTP Server Settings
If you’re using a Gmail account, these are the SMTP Server details:
- SMTP Server: smtp.gmail.com
- SMTP username: Complete Gmail address
- SMTP password: Your Gmail password
- SMTP port (TLS): 587
- SMTP port (SSL): 465
- SMTP TLS/SSL required: yes
Outlook SMTP Server Settings
For Outlook accounts, these are the SMTP Server settings:
- SMTP Server: smtp.office365.com
- SMTP Username: Complete Outlook email address
- SMTP Password: Your Outlook password
- SMTP Port: 587
- SMTP TLS/SSL Required: Yes
Live or Hotmail SMTP Server Settings
For Live or Hotmail accounts, these are the SMTP Server settings:
- SMTP Server: smtp.live.com
- SMTP Username: Complete Live/Hotmail email address
- SMTP Password: Your Windows Live Hotmail password
- SMTP Port: 587
- SMTP TLS/SSL Required: Yes
If you’re using another email provider, you need to search for its SMTP Server settings. Now, you have everything ready to start sending emails with your ESP32.
Send an Email with HTML or Raw Text with ESP32 (Arduino IDE)
The following code sends an email via SMTP Server with HTML or raw text. For demonstration purposes, the ESP32 sends an email once when it boots. Then, you should be able to modify the code and integrate it into your own projects.
Don’t upload the code yet, you need to make some modifications to make it work for you.
/*
Rui Santos
Complete project details at:
- ESP32: https://RandomNerdTutorials.com/esp32-send-email-smtp-server-arduino-ide/
- ESP8266: https://RandomNerdTutorials.com/esp8266-nodemcu-send-email-smtp-server-arduino/
Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files.
The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software.
Example adapted from: https://github.com/mobizt/ESP-Mail-Client
*/
// To send Emails using Gmail on port 465 (SSL), you need to create an app password: https://support.google.com/accounts/answer/185833
#include <Arduino.h>
#if defined(ESP32)
#include <WiFi.h>
#elif defined(ESP8266)
#include <ESP8266WiFi.h>
#endif
#include <ESP_Mail_Client.h>
#define WIFI_SSID "REPLACE_WITH_YOUR_SSID"
#define WIFI_PASSWORD "REPLACE_WITH_YOUR_PASSWORD"
#define SMTP_HOST "smtp.gmail.com"
#define SMTP_PORT 465
/* The sign in credentials */
#define AUTHOR_EMAIL "[email protected]"
#define AUTHOR_PASSWORD "YOUR_EMAIL_PASS"
/* Recipient's email*/
#define RECIPIENT_EMAIL "[email protected]"
/* The SMTP Session object used for Email sending */
SMTPSession smtp;
/* Callback function to get the Email sending status */
void smtpCallback(SMTP_Status status);
void setup(){
Serial.begin(115200);
Serial.println();
Serial.print("Connecting to AP");
WiFi.begin(WIFI_SSID, WIFI_PASSWORD);
while (WiFi.status() != WL_CONNECTED){
Serial.print(".");
delay(200);
}
Serial.println("");
Serial.println("WiFi connected.");
Serial.println("IP address: ");
Serial.println(WiFi.localIP());
Serial.println();
/** Enable the debug via Serial port
* none debug or 0
* basic debug or 1
*/
smtp.debug(1);
/* Set the callback function to get the sending results */
smtp.callback(smtpCallback);
/* Declare the session config data */
ESP_Mail_Session session;
/* Set the session config */
session.server.host_name = SMTP_HOST;
session.server.port = SMTP_PORT;
session.login.email = AUTHOR_EMAIL;
session.login.password = AUTHOR_PASSWORD;
session.login.user_domain = "";
/* Declare the message class */
SMTP_Message message;
/* Set the message headers */
message.sender.name = "ESP";
message.sender.email = AUTHOR_EMAIL;
message.subject = "ESP Test Email";
message.addRecipient("Sara", RECIPIENT_EMAIL);
/*Send HTML message*/
String htmlMsg = "<div style=\"color:#2f4468;\"><h1>Hello World!</h1><p>- Sent from ESP board</p></div>";
message.html.content = htmlMsg.c_str();
message.html.content = htmlMsg.c_str();
message.text.charSet = "us-ascii";
message.html.transfer_encoding = Content_Transfer_Encoding::enc_7bit;
/*
//Send raw text message
String textMsg = "Hello World! - Sent from ESP board";
message.text.content = textMsg.c_str();
message.text.charSet = "us-ascii";
message.text.transfer_encoding = Content_Transfer_Encoding::enc_7bit;
message.priority = esp_mail_smtp_priority::esp_mail_smtp_priority_low;
message.response.notify = esp_mail_smtp_notify_success | esp_mail_smtp_notify_failure | esp_mail_smtp_notify_delay;*/
/* Set the custom message header */
//message.addHeader("Message-ID: <[email protected]>");
/* Connect to server with the session config */
if (!smtp.connect(&session))
return;
/* Start sending Email and close the session */
if (!MailClient.sendMail(&smtp, &message))
Serial.println("Error sending Email, " + smtp.errorReason());
}
void loop(){
}
/* Callback function to get the Email sending status */
void smtpCallback(SMTP_Status status){
/* Print the current status */
Serial.println(status.info());
/* Print the sending result */
if (status.success()){
Serial.println("----------------");
ESP_MAIL_PRINTF("Message sent success: %d\n", status.completedCount());
ESP_MAIL_PRINTF("Message sent failled: %d\n", status.failedCount());
Serial.println("----------------\n");
struct tm dt;
for (size_t i = 0; i < smtp.sendingResult.size(); i++){
/* Get the result item */
SMTP_Result result = smtp.sendingResult.getItem(i);
time_t ts = (time_t)result.timestamp;
localtime_r(&ts, &dt);
ESP_MAIL_PRINTF("Message No: %d\n", i + 1);
ESP_MAIL_PRINTF("Status: %s\n", result.completed ? "success" : "failed");
ESP_MAIL_PRINTF("Date/Time: %d/%d/%d %d:%d:%d\n", dt.tm_year + 1900, dt.tm_mon + 1, dt.tm_mday, dt.tm_hour, dt.tm_min, dt.tm_sec);
ESP_MAIL_PRINTF("Recipient: %s\n", result.recipients);
ESP_MAIL_PRINTF("Subject: %s\n", result.subject);
}
Serial.println("----------------\n");
}
}
You need to insert your network credentials as well as set the sender email, SMTP Server details, recipient, and message.
How the Code Works
This code is adapted from an example provided by the library. The example is well commented so that you understand what each line of code does. Let’s just take a look at the relevant parts that you need or may need to change.
First, insert your network credentials in the following lines:
#define WIFI_SSID "REPLACE_WITH_YOUR_SSID"
#define WIFI_PASSWORD "REPLACE_WITH_YOUR_PASSWORD"Insert your SMTP server settings. If you’re using a Gmail account to send the emails, these are the settings:
#define SMTP_HOST "smtp.gmail.com"
#define SMTP_PORT 465Insert the sender email sign in credentials (complete email and app password you created previously).
#define AUTHOR_EMAIL "[email protected]"
#define AUTHOR_PASSWORD "YOUR_EMAIL_PASS"Insert the recipient email:
#define RECIPIENT_EMAIL "[email protected]"Set the message headers in the following lines in the setup()—sender name, sender email, email subject, and the recipient name and email:
/* Set the message headers */
message.sender.name = "ESP";
message.sender.email = AUTHOR_EMAIL;
message.subject = "ESP Test Email";
message.addRecipient("Sara", RECIPIENT_EMAIL);In the following lines, set the content of the message (raw text) in the textMsg variable:
//Send raw text message
String textMsg = "Hello World - Sent from ESP board";
message.text.content = textMsg.c_str();
message.text.charSet = "us-ascii";
message.text.transfer_encoding = Content_Transfer_Encoding::enc_7bit;If you want to send HTML text instead, uncomment the following lines— you should insert your HTML text in the htmlMsg variable.
/*Send HTML message*/
/*String htmlMsg = "<div style=\"color:#2f4468;\"><h1>Hello World!</h1><p>- Sent from ESP board</p></div>";
message.html.content = htmlMsg.c_str();
message.html.content = htmlMsg.c_str();
message.text.charSet = "us-ascii";
message.html.transfer_encoding = Content_Transfer_Encoding::enc_7bit;*/Finally, the following lines send the message:
if (!MailClient.sendMail(&smtp, &message))
Serial.println("Error sending Email, " + smtp.errorReason());Demonstration
Upload the code to your ESP32. After uploading, open the Serial Monitor at a baud rate of 115200. Press the ESP32 Reset button.
If everything went as expected you should get a similar message in the Serial Monitor.
Check your email account. You should have received an email from your ESP32 board.
If you set the option to send a message with HTML text, this is what the message looks like:
If you’ve enable the raw text message, this is the email that you should receive.
Send Attachments via Email with ESP32 (Arduino IDE)
In this section, we’ll show you how to send attachments in your emails sent by the ESP32. We’ll show you how to send .txt files or pictures. This can be useful to send a .txt file with sensor readings from the past few hours or to send a photo captured by an ESP32-CAM.
For this tutorial, the files to be sent should be saved on the ESP32 filesystem (SPIFFS).
Upload files to SPIFFS
To send files via email, these should be saved on the ESP32 filesystem (SPIFFS). We’ll upload a picture and a .txt file to the ESP32 SPIFFS using the ESP32 Filesystem Uploader plugin for Arduino IDE. Follow the next tutorial to install the plugin if you don’t have it installed yet:
Create a new Arduino sketch and save it. Go to Sketch > Show Sketch folder. Inside the Arduino sketch folder, create a folder called data. Move a .jpg file and .txt file to your data folder.
Alternatively, you can click here to download the project folder.
Note: with the default code, your files must be named image.png and text_file.txt. Alternatively, you can modify the code to import files with a different name.
We’ll be sending these files:
Your folder structure should look as follows (download project folder):
After moving the files to the data folder, in your Arduino IDE, go to Tools > ESP32 Sketch Data Upload and wait for the files to be uploaded.
You should get a success message on the debugging window. If the files were successfully uploaded, move on to the next section.
Note: if you start seeing many dots ….____…..____ being printed on the debugging window, you need to hold the ESP32 on-board BOOT button for the files to be uploaded.
Code
The following code sends an email with a .txt file and a picture attached. Before uploading the code, make sure you insert your sender email settings and your recipient email.
/*
Rui Santos
Complete project details at:
- ESP32: https://RandomNerdTutorials.com/esp32-send-email-smtp-server-arduino-ide/
Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files.
The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software.
Example adapted K. Suwatchai (Mobizt): https://github.com/mobizt/ESP-Mail-Client Copyright (c) 2021 mobizt
*/
// To send Emails using Gmail on port 465 (SSL), you need to create an app password: https://support.google.com/accounts/answer/185833
// The file systems for flash and sd memory can be changed in ESP_Mail_FS.h.
#include <Arduino.h>
#if defined(ESP32)
#include <WiFi.h>
#elif defined(ESP8266)
#include <ESP8266WiFi.h>
#endif
#include <ESP_Mail_Client.h>
#define WIFI_SSID "REPLACE_WITH_YOUR_SSID"
#define WIFI_PASSWORD "REPLACE_WITH_YOUR_PASSWORD"
#define SMTP_HOST "smtp.gmail.com"
/** The smtp port e.g.
* 25 or esp_mail_smtp_port_25
* 465 or esp_mail_smtp_port_465
* 587 or esp_mail_smtp_port_587
*/
#define SMTP_PORT 465
/* The log in credentials */
#define AUTHOR_EMAIL "[email protected]"
#define AUTHOR_PASSWORD "YOUR_EMAIL_PASS"
/* Recipient's email*/
#define RECIPIENT_EMAIL "[email protected]"
/* The SMTP Session object used for Email sending */
SMTPSession smtp;
/* Callback function to get the Email sending status */
void smtpCallback(SMTP_Status status);
void setup(){
Serial.begin(115200);
Serial.println();
Serial.print("Connecting to AP");
WiFi.begin(WIFI_SSID, WIFI_PASSWORD);
while (WiFi.status() != WL_CONNECTED){
Serial.print(".");
delay(200);
}
Serial.println("");
Serial.println("WiFi connected.");
Serial.println("IP address: ");
Serial.println(WiFi.localIP());
Serial.println();
if (!SPIFFS.begin(true)) {
Serial.println("An error has occurred while mounting SPIFFS");
}
else{
Serial.println("SPIFFS mounted successfully");
}
/** Enable the debug via Serial port
* none debug or 0
* basic debug or 1
*/
smtp.debug(1);
/* Set the callback function to get the sending results */
smtp.callback(smtpCallback);
/* Declare the session config data */
ESP_Mail_Session session;
/* Set the session config */
session.server.host_name = SMTP_HOST;
session.server.port = SMTP_PORT;
session.login.email = AUTHOR_EMAIL;
session.login.password = AUTHOR_PASSWORD;
session.login.user_domain = "mydomain.net";
/* Declare the message class */
SMTP_Message message;
/* Enable the chunked data transfer with pipelining for large message if server supported */
message.enable.chunking = true;
/* Set the message headers */
message.sender.name = "ESP Mail";
message.sender.email = AUTHOR_EMAIL;
message.subject = "Test sending Email with attachments and inline images from SD card and Flash";
message.addRecipient("Sara", RECIPIENT_EMAIL);
/** Two alternative content versions are sending in this example e.g. plain text and html */
String htmlMsg = "This message contains attachments: image and text file.";
message.html.content = htmlMsg.c_str();
message.html.charSet = "utf-8";
message.html.transfer_encoding = Content_Transfer_Encoding::enc_qp;
message.priority = esp_mail_smtp_priority::esp_mail_smtp_priority_normal;
message.response.notify = esp_mail_smtp_notify_success | esp_mail_smtp_notify_failure | esp_mail_smtp_notify_delay;
/* The attachment data item */
SMTP_Attachment att;
/** Set the attachment info e.g.
* file name, MIME type, file path, file storage type,
* transfer encoding and content encoding
*/
att.descr.filename = "image.png";
att.descr.mime = "image/png"; //binary data
att.file.path = "/image.png";
att.file.storage_type = esp_mail_file_storage_type_flash;
att.descr.transfer_encoding = Content_Transfer_Encoding::enc_base64;
/* Add attachment to the message */
message.addAttachment(att);
message.resetAttachItem(att);
att.descr.filename = "text_file.txt";
att.descr.mime = "text/plain";
att.file.path = "/text_file.txt";
att.file.storage_type = esp_mail_file_storage_type_flash;
att.descr.transfer_encoding = Content_Transfer_Encoding::enc_base64;
/* Add attachment to the message */
message.addAttachment(att);
/* Connect to server with the session config */
if (!smtp.connect(&session))
return;
/* Start sending the Email and close the session */
if (!MailClient.sendMail(&smtp, &message, true))
Serial.println("Error sending Email, " + smtp.errorReason());
}
void loop()
{
}
/* Callback function to get the Email sending status */
void smtpCallback(SMTP_Status status){
/* Print the current status */
Serial.println(status.info());
/* Print the sending result */
if (status.success()){
Serial.println("----------------");
ESP_MAIL_PRINTF("Message sent success: %d\n", status.completedCount());
ESP_MAIL_PRINTF("Message sent failled: %d\n", status.failedCount());
Serial.println("----------------\n");
struct tm dt;
for (size_t i = 0; i < smtp.sendingResult.size(); i++){
/* Get the result item */
SMTP_Result result = smtp.sendingResult.getItem(i);
time_t ts = (time_t)result.timestamp;
localtime_r(&ts, &dt);
ESP_MAIL_PRINTF("Message No: %d\n", i + 1);
ESP_MAIL_PRINTF("Status: %s\n", result.completed ? "success" : "failed");
ESP_MAIL_PRINTF("Date/Time: %d/%d/%d %d:%d:%d\n", dt.tm_year + 1900, dt.tm_mon + 1, dt.tm_mday, dt.tm_hour, dt.tm_min, dt.tm_sec);
ESP_MAIL_PRINTF("Recipient: %s\n", result.recipients);
ESP_MAIL_PRINTF("Subject: %s\n", result.subject);
}
Serial.println("----------------\n");
}
}
How the code works
This code is very similar to the previous one, so we’ll just take a look at the relevant parts to send attachments.
In the setup(), you need to initialize SPIFFS:
if(!SPIFFS.begin(true)) {
Serial.println("An Error has occurred while mounting SPIFFS");
return;
}You need to create an attachment as follows:
/* The attachment data item */
SMTP_Attachment att;Then, add the attachment details: filename, MIME type, file path, file storage type, and transfer encoding. In the following lines, we’re sending the image file.
att.descr.filename = "image.png";
att.descr.mime = "image/png";
att.file.path = "/image.png";
att.file.storage_type = esp_mail_file_storage_type_flash;
att.descr.transfer_encoding = Content_Transfer_Encoding::enc_base64;Finally, add the attachment to the message:
message.addAttachment(att);If you want to send more attachments, you need to call the following line before adding the next attachment:
message.resetAttachItem(att);Then, enter the details of the other attachment (text file):
att.descr.filename = "text_file.txt";
att.descr.mime = "text/plain";
att.file.path = "/text_file.txt";
att.file.storage_type = esp_mail_file_storage_type_flash;
att.descr.transfer_encoding = Content_Transfer_Encoding::enc_base64;And add this attachment to the message:
message.addAttachment(att);Finally, you just need to send the message as you did with the previous example:
if (!MailClient.sendMail(&smtp, &message, true))
Serial.println("Error sending Email, " + smtp.errorReason());Demonstration
After uploading the code, open the Serial Monitor at a baud rate of 115200 and press the on-board EN/RESET button. If everything goes smoothly, you should get a similar message on the Serial Monitor.
Check the recipient’s email address. You should have a new email with two attachments.
Wrapping Up
In this tutorial you’ve learned how to send emails with the ESP32 using an SMTP Server. For this method to work, the ESP32 should have access to the internet.
If you don’t want to use an SMTP Server, you can also write a PHP script to send email notifications with the ESP32 or ESP8266 board.
You’ve learned how to send a simple email with text and with attachments. When using attachments, these should be save on the ESP32 filesystem (SPIFFS) or on a microSD card (not covered in this tutorial).
The examples presented show how to send a single email when the ESP32 boots. The idea is to modify the code and include it in your own projects. For example, it can be useful to send a .txt file with the sensor readings, send a photo captured with the ESP32-CAM, use deep sleep to wake up your board every hour and send an email with data, etc.
We hope you’ve find this tutorial interesting.
To learn more about the ESP32, take a look at our resources:
- Learn ESP32 with Arduino IDE
- Build Web Servers with ESP32 and ESP8266 eBook
- MicroPython Programming with ESP32 and ESP8266
- More ESP32 resources…
Thanks for reading.
Dear Rui and Sara
Excellent work, this makes me very happy!
Thanks a lot
Best Regards
You’re welcome!
When I run the program, this message appeared
SPIFFS Not Supported on avr
Did you select the ESP32 board? Does your code still compile and upload? Sometimes you’ll see those warning messages and you can ignore them
Hello,
I would like to thank you for your tutorials.
I tried to send email with a wemos D1 mini using the code in this blog and I got the following error:
/home/samorai/Arduino/libraries/ESP32_Mail_Client/src/ssl_client32.h:32:30: fatal error: mbedtls/platform.h: No such file or directory
#include “mbedtls/platform.h”
I am using the latest IDE version.
Any idea how to solve this?
Thanks and regards
Hello,
This issue was solved by downloading https://tls.mbed.org/download/start/mbedtls-2.16.4-apache.tgz and including it in /home/samorai/Arduino/libraries/ESP32_Mail_Client folder.
Regards
Great!
Thanks for sharing that.
Regards,
Sara
Hey whenever I try to upload the code to my ESP32 I keep getting this error and II have no idea what to do. Help!
Arduino: 1.8.17 Hourly Build 2021/09/06 02:33 (Windows 10), Board: “Arduino Uno”
In file included from C:\Users\huntk\Documents\Arduino\libraries\ESP_Mail_Client\src/ESP_Mail_Client.h:112:0,
from C:\Users\huntk\Documents\Arduino\ESP32_Email_Alpha\ESP32_Email_Alpha.ino:20:
C:\Users\huntk\Documents\Arduino\libraries\ESP_Mail_Client\src/extras/ESPTimeHelper/ESPTimeHelper.h:31:10: fatal error: vector: No such file or directory
#include
^~~~~~~~
compilation terminated.
exit status 1
Error compiling for board Arduino Uno.
This report would have more information with
“Show verbose output during compilation”
option enabled in File -> Preferences.
Howdy,
I’ve included this file into my ESP32_Mail_Client folder and still receive the same error when compiling. Does anyone have any solutions?
Thanks
I’ve got the code in my Arduino IDE, but cannot compile. I am seeing the same error.
When I include this folder in src > mbedtls the includes seem to work, but now I have illicited this response from the code. >…/ESP32_Mail_Client/src/ESP32_MailClient.h:37:18: fatal error: ETH.h: No such file or directory
>#include “ETH.h”
I’m going to keep chasing this, but I feel like I have some library mismatch or version wrong. Any insights?
Working with an 8266 – and just realizing as I typed it out that may be the source of my trouble.
Hi Zach.
Unfortunately, this project is not compatible with the ESP8266.
Regards,
Sara
Another top class tutorial from RNT ! Kudos.
I was looking for this exact tutorial for a long time and you guys did it. Worked first shot … both the HTML and Text version mails.
Great. Now I can get a mail when my UPS battery needs charging or when my sump water level drops below the danger mark or …. the list is endless.
That’s great!
I’m glad you found it useful.
Regards,
Sara 😀
Was getting many compilation until I installed version 1.0.4 for ESP32.
Now the first text example works, will try the rest soon,
Thanks!
Compilation errors, I meant.
If you got this obscure error below,
#error: architecture or board not supported
It has to do with the
#include “ESP32_MailClient.h”
is calling an old SD card library,
When I got this error, the compiler is using a very old library that doesn’t recognize ESP32. I removed all the old libraries until the compiler is using the ESP32 SD card library – see below.
Using library SD at version 1.0.5 in folder: C:\Users\one\Documents\Arduino\hardware\esp32\arduino-esp32-master\libraries\SD
Hope this helps!
Hi.
Thanks for sharing that.
I will be helpful for our readers.
Regards,
Sara
I have been looking for exactly this! Just great you posted it.
I have the recommended ESP32 board, but the compiler tells me: “”Error compiling for board DOIT ESP32 DEVKIT V1”. Could you please help me out? Any pointers?
I think A Lee had the same issue, and … the fix. I would like to try it. How do I remove and old library? I know …. rookie question.
When you get the error, what part of the code gets highlighted?
That indicates where the error is.
Regards,
Sara
Thank you for your quick response. In the meantime I have completely removed the entire Arduino installation and its libraries and reinstalled a clean version. It compiles! 🙂
If you go to File Preference and click Show Verbose Output during compilation. Then you will see a lot of messages on the screen. After the compiler stopped, you would see this message on the screen in red.
exit status 1
Error compiling for board ESP32 Dev Module.
Scroll up and see where is error comes from.
C:\Users\One\Documents\Arduino\libraries\SD\src/utility/Sd2PinMap.h:524:2: error: #error Architecture or board not supported.
#error Architecture or board not supported.
^
Sd2PinMap.h is a file under the SD directory. My Google search found not much with this type of error. One poster said the library doesn’t suppose the lastest board. It means sense because the error is Architecture or board not supported.
I figured – the SD library probably is “old”. I started moving it to another drive in my PC and recompile the sketch. Below is the compiler telling which library it was using to compile the sketch.
Multiple libraries were found for “SD.h”
Used: C:\Users\One\Documents\Arduino\libraries\SD
Not used: C:\Users\One\Documents\Arduino\hardware\esp32\arduino-esp32-master\libraries\SD
I moved the SD directory that it was using to another drive.
Then it complied with no error. I scroll up the screen and saw it was using the esp32 library.
Using library SD at version 1.0.5 in folder: C:\Users\One\Documents\Arduino\hardware\esp32\arduino-esp32-master\libraries\SD
It works for me. Good luck!
Thank you A Lee for your extensive response!
Hello, thank you for this tutorial. I am getting the following error message. Your thoughts, please. Thanks, Mac
Connecting to SMTP server…
SMTP server connected, wait for response…
Identification…
Authentication…
Sign in…
Error, login password is not valid
Error sending Email, login password is not valid
Hi.
That means that the password you’ve inserted is not correct for the sender email.
Regards,
Sara
I have the same issue.
I just made the email account, so I know it’s the right PW.
Does it have issue with the ‘#’ symbol?
Andy
Hi Andy.
Double-check that you have access to less secure apps enable.
Sometimes Gmail changes that option without our permission.
Regards,
Sara
Triple checked.
I even set up a new Outlook account to see if it was Gmail.
I get the same error.
Should I try another email?
Andy
Hi Andy.
Honestly, I don’t know.
It worked fine for me using a Gmail account.
If you change to another email provider, check that you have the right smtp settings for that email provier.
Regards,
Sara
Hi,
you should turn on Allow less secure apps on Gmail. This will solve your problem.
Hello Macin,
I get the same issue but not always. Issue does not come from my password or Id because sometimes it works ! did you find a solution to your issue ?
I’ve had the same issue, though the password was correct. I’ve done the following and it now works well:
– Enable less secure apps
– Enable 2-Step verification
– Then Manage your google account>Security>Sign in to Google>App password>create a new app password which can only be used in the device you choose.
The generated password should be placed on the arduino sketch replacing your main accounts password.
If you have several ESP32 (or other devices) you should generate an app password per device.
Hope this helps.
would you share the place where i should place the app password in the Arduino ide code?
Hi.
Insert it on the following line:
#define AUTHOR_PASSWORD “YOUR_EMAIL_PASS”
Regards,
Sara
Hello, First of all, thanks for this post.
I want to send an email when my Magnetic switch is HIGH. Magnetic Switch is connected to ESP32. So in which part of the code I should add this?
It might be a simple question but I am new in Arduino, and ESP32, so please help me.
Hello and well done for your work.
I am new to the subject and I don’t know what “SSID” is or where to find it.
Thank you for informing me.
Regards
Hi Jean.
SSID is the name of your internet network (Wi-Fi).
Usually, there’s a sticker below the router with the wi-fi name.
Also, if you search for Wi-Fi networks with your smartphone, you’ll find its name.
Regards,
Sara
Thank you for your reply Sara.
Regards.
Hi all, is there a library like “ESP32_MailClient.h” for ESP8266?
Or how can I use this code for ESP8…
Hi Tom.
This code is not compatible with ESP8266.
You can use this library to send emails with ESP8266: https://github.com/xreef/EMailSender
Regards,
Sara
dear if I want to send voltage value , what I should do since smtpData.setMessage(“ALI SHAMI testing “, false); support only char . thxx in advance
Hi.
You can take a look at this project that sends temperature values via email. Instead of temperature values, you can send voltage.
https://randomnerdtutorials.com/esp32-email-alert-temperature-threshold/
You need something as follows, for example:
String emailMessage = String(“Testing: “) + String(voltage)
Then, use:
smtpData.setMessage(emailMessage, true);
I hope this helps.
Regards,
Sara
Hello, thank you very much for the publications, you are great.
I have finished your project and I receive the email without the files, this is what I see on the serial monitor:
Connecting
WiFi connected.
Preparing to send email
Connecting to SMTP server …
SMTP server connected, wait for response …
Identification …
Authentication …
Sign in …
Sending Email header …
Sending Email body …
Sending attachments …
Finish …
Finished
Email sent successfully
—————-
however in the “data” folder are your files. Sorry if it’s a silly question but I’m a newbie.😊
Hi Rafa.
Thanks for your question. Did you upload the files to the ESP32 SPIFFS?
After moving the files to the data folder, you need to go to Tools > ESP32 Data Sketch Upload
Regards,
Sara
Thanks for your response and sorry for the delay. It is possible that this is the problem, I have several Arduino installations and maybe it confused me. Thank you
Hi Rafa.
Use only one Arduino installation to avoid problems and conflicts with libraries.
Regards,
Sara
Dear Rui and Sara
I thank U for your Excellent work,
I have a liiiitle problem with the attached file: it is on the SD card and I the error is in this lines :
MailClient.sdBegin(18, 19, 23, 5); // (SCK, MISO, MOSI, CS)
if(!SD.begin()){
Serial.println(“Card Mount Failed”);
return “”;
}
the error is : exit status 1
return-statement with a value, in function returning ‘void’ [-fpermissive]
I beg your help, superplease!
Simplemente borra las comillas es un error de tecleado.
Hi Rui and Sara,
It is awesome…thank you so much. Works as expected at first try with Gmail account.
Best regards,
Tondium
Great! 🙂
Hi,
when I compile the sketch send email on a ESP32 dev board, I get several compiler errors. Which library is missing?
Here the errors:
/Users/myName/Documents/Arduino/hardware/espressif/esp32/libraries/ESP32-Mail-Client/src/ssl_client32.cpp: In function ‘int start_ssl_client(sslclient_context32*, const char*, uint32_t, int, const char*, const char*, const char*, const char*, const char)’:
/Users/myName/Documents/Arduino/hardware/espressif/esp32/libraries/ESP32-Mail-Client/src/ssl_client32.cpp:101:48: error: cannot call member function ‘int WiFiGenericClass::hostByName(const char, IPAddress&)’ without object
if (!WiFiGenericClass::hostByName(host, srv))
^
/Users/myName/Documents/Arduino/hardware/espressif/esp32/libraries/ESP32-Mail-Client/src/ssl_client32.cpp:271:85: error: ‘mbedtls_ssl_conf_psk’ was not declared in this scope
(const unsigned char *)pskIdent, strlen(pskIdent));
^
/Users/myName/Documents/Arduino/hardware/espressif/esp32/libraries/ESP32-Mail-Client/src/ESP32_MailClient.cpp: In member function ‘bool ESP32_MailClient::waitIMAPResponse(IMAPData&, uint8_t, int, int, int, std::__cxx11::string)’:
/Users/myName/Documents/Arduino/hardware/espressif/esp32/libraries/ESP32-Mail-Client/src/ESP32_MailClient.cpp:2460:9: error: ‘transform’ is not a member of ‘std’
std::transform(tmp.begin(), tmp.end(), tmp.begin(), ::tolower);
^
/Users/myName/Documents/Arduino/hardware/espressif/esp32/libraries/ESP32-Mail-Client/src/ESP32_MailClient.cpp:2629:13: error: ‘sort’ is not a member of ‘std’
std::sort(imapData._msgNum.begin(), imapData._msgNum.end(), compFunc);
^
/Users/myName/Documents/Arduino/hardware/espressif/esp32/libraries/ESP32-Mail-Client/src/ESP32_MailClient.cpp: In member function ‘void IMAPData::setFetchUID(const String&)’:
/Users/myName/Documents/Arduino/hardware/espressif/esp32/libraries/ESP32-Mail-Client/src/ESP32_MailClient.cpp:3702:3: error: ‘transform’ is not a member of ‘std’
std::transform(tmp.begin(), tmp.end(), tmp.begin(), ::toupper);
^
Is there still a chance that I get an answer to my question? Thanks!
Hi Kurt.
I’m sorry for taking so long to see your comment.
I think you have some problem with the library.
I suggest that you delete the library from the libraries folder and try to install it again.
Regards,
Sara
Love this project, easy to follow and understand. Works great until I use a battery to power the ESP32. I tried different cables,batteries, power supply with no success in sending. Nothing happens. Plugged it into a wall jack with the 5v adapter and it works fine.
What am I missing.
Hi Karel.
What battery are you using to power the ESP32?
You can take a look at this project (ignore the solar panels, just take a look at the battery side): https://randomnerdtutorials.com/power-esp32-esp8266-solar-panels-battery-level-monitoring/
Regards,
Sara
Hi Sara
I’m using a 9V with the ardunio power board and have also tried the LM317 regulator set to 5v. No go. As soon as I switch to the micro usb email arrives no problem.???
I’m at a loss?
hello,
can you set this project to work that
door status monitormade by you? because that project doesnt work anymore because of IFTTT upgrade….thanks
The code works great, my question is how to add multiple recipients for a message.
Hi Guys!
I was trying to send a sensor value (MQ-2) by e-mail, using the Wemos Lolin Oled and your code. But all the analog input PINs go to 100%… And I don’t know why!
Do you have some idea that is happening?
Best,
Ricardo
Sorry! Without the email code, I can see the sensor value on Oled display. But when the email code is added, the sensor value goes to 4095…
Hi Ricardo.
You’re probably using an ADC2 analog pin.
ADC2 doesn’t work well with Wi-Fi.
You must choose an ADC1 pin. See the ESP32 pinout guide here: https://randomnerdtutorials.com/esp32-pinout-reference-gpios/
Regards,
Sara
Thank you!
In fact, I’m using the Esp32 Oled board. But I connected the sensor to GPIO 36 (that’s an ADC1) and now the analogRead () is working.
Thanks again!
Ricardo
Is there any requirement of doing some connections with esp32.
Hi.
What do you mean?
Connections with sensors and outputs?
Take a look at this guide: https://randomnerdtutorials.com/esp32-pinout-reference-gpios/
Regards,
Sara
Thanks the Santos to provide a lot of good projects on this site. One of my struggles is to know what IP is assigned to a “webserver” by the wireless router if there is no “display” available to show the IP address. Below are the changes that I made to the test email sketch to make it possible.
Modify the emailSubject as a String; add localIP as a variable
String emailSubject;
IPAddress localIP;
Add the following at the end of the Setup
Serial.print(“IP: “);Serial.println(WiFi.localIP());
localIP = WiFi.localIP();
emailSubject =String( localIP[0]) + “.” + String( localIP[1])+ “.” + String( localIP[2]) + “.” + String( localIP[3]);
SMTPsendmail();
When you receive the email from your project, the IP address is on the Subject.
Have fun!
Rui and Sara, I’m here from BRasil to accompany you. Congratulations!
Which command do I use to delete the SPIFFS file after it is sent?
Hi.
You can use the following command:
SPIFFS.remove(“/filename”);
Replace filename with the name of the file you want to remove. You also need to include the file extension.
Regards,
Sara
What about new version ESP32_Mail_Client.h?
Is it necesary to change?
Thanks a lot
Hello, great article and this library is working very well ! Thanks.
Thanks for this awesome tutorial.
I can generate an email when the code is placed in setup(), but if I place it anywhere else I get
[E][ssl_client32.cpp:63] handle_error(): SSL – Memory allocation failed
[E][ssl_client32.cpp:65] handle_error(): MbedTLS message code: -32512
[E][WiFiClientSecureESP32.cpp:179] connect(): start_ssl_client: -32512
Any idea why this might be happening?
Thanks for any clues!
Further info: when placed before (blocking) BLE scan function, no problem, when placed after, fails. So some resource used by BLE scan is preventing email?
When using with Gmail, as we know we have to enable the low security mode on the Gmail account in question.
But there is a problem in that if you don’t often send an email using this account Google will automatically turn that function back off again after a certain period of time ( how long ? – I don’t know)
and your account will now
I have that working fine, but in my case I only want to send a notification email as a very sporadic event
This means there is a good chance that Google have disabled the low security mode again and my notification email will fail to get thru
Is there some function/command ( other than an sending a spurious email) I can send to the gmail account (say once a day/week) to keep the account awake and ensure that Google don’t change the low security mode against my wishes
Hi, I suggest to send an “I’m alive” email once a week, or so.
Yes – thats what I decided to do in the end
That email acts as the confirmation to me that Gmail is still working
(currently it gets sent every night @ 00:00 – possibly overkill)
Hi,
i am trying and following al of the sketches ,
but i keep getting :
‘SMTPData’ does not name a type.(just copied the code)
can you tell me how to fix this? and why this happens
i used the latest esp32 mail client
thanks
I had the same error, but it was because I had a brain fart. Be sure the correct board type is selected in your Arduino IDE.. In my case I had a non ESP32 Board selected in error.
Hi, did you find the solution? I’m having the same problem – the correct board is selected and all the libraries should be up to date.
thanks!
Not sure if this has been already mentioned, but it’s not a good idea to make the gmail account “less secure”. Instead, create a pecial password at “Sign in with App Passwords”.
Best regards.
i would love to interface a gps sensor with esp32 and send a panic email and text message with the gps location everytime danger is sensed by a person holding the device. the device could be a bag with a push button
Very well-written tutorial. Great work. Thank you.
Thanks 🙂
why dont we use LittleFS in esp32?
I am getting an error report: ‘ESP_MAIL_PRINTF’ was not declared in this scope
What could be the reason for this error report?
Hi.
What’s the board that you’re using?
MAke sure you are using the latest version of the library.
Regards,
Sara
I found the answer to my question: there was an old version of the ESP_Mail_Client.h in my libraries folder, which was used during compialtion. Deleting that old version solved the problem.
Yes. That was what I thought.
Regards,
Sara
Yes indeed, good thinking. Thank you very much
Thanks Sara and Rui for such a complete, clear and educational tutorial! It was just what I needed. I will definitely be checking out your other tutorials. The demo code works great on my Adafruit Feather Huzzah32 board, with Yahoo email.
A tip for Yahoo email users: I used “smtp.mail.yahoo.com” and port 465. I received “authentication failure” messages using my normal login and password. The only solution I found was to create an “App Password” on your Yahoo account web page (Account Info -> Account Security -> look for App Password section). Use the App Password in place of your normal password, and it works great!
Thanks for sharing that tip.
Regards,
Sara
Hi Rui and Sara,
Thank you for all the good and well structered information in all your tutorials. You’re the best!
In this one, I have a particular doubt.
I implemented this on my ESP32 and have sended emails with HTML (no attachements). Worked perfectly.
Is it possible to insert in the “String htmlMsg” arduino variables? How should I do that?
For example:
String htmlMsg = ”
Hello World!Energy consumed: INSERT HERE ARDUINO VARIABLE
“;
Thank you in advance!
Hi.
Yes, you can concatenate the htmlMsg String with arduino variables.
Regards,
Sara
Hey, I love your tutorials.
I tried your code month ago and it went great.
But now I got back to different project and it doesn’t work.
After the message “starting socket” I always get an error message “could not get ip from host”.
Can you please help me?
Having an ESP send an email is a feature I took one step further, most cellular phone providers allow a feature they don’t tell many people about. In most cases you will need to contact the tech support to activate it.
It can take several minutes to receive an email, depending on the frequency your device checks for new email. Receiving a text message is usually much quicker. Did you know you can send a plain text email message to your cellular phone number and receive it as a text message?
For an example, I have a google mail account. I have also rigged up a 433 RF receiver to an ESP32. When an RF transmitter button is pressed and identified by the ESP, it sends an email to [email protected] and within a few seconds I receive a text message on my cellular phone.
That’s a great tip!
Thanks for sharing.
Regards,
Sara
Excellent!!!
I learn so much from your examples. Thank you!
Once again – great tutorial – many thanks.
Will you be doing another one for receiving emails?
I want to email configuration details to my ESP32 either within the message contents or as an attached text file which I can then write to flash memory. This will be much better and easier than having to use the arduino ‘upload’ and can be done without having to use the Arduino IDE.
Hi.
At the moment, we don’t have any tutorials about readings emails.
But take a look at the following examples that might help:
https://github.com/mobizt/ESP-Mail-Client/tree/master/examples/IMAP
Regards,
Sara
Dear Rui and Sara,
Thanks very much for this tutorial. The first part, sending STMP e-mail message with my ESP32 worked perfectly which is why I was surprised at receiving the following error when trying to compile the Send Attachments tutorial. I was particularly surprised since the sketches are very similar. I performed the SPIFFS plug-in and attachment upload OK and copied over your exact code without changing any of the WiFi, or e-mail parameters as a double check and still received the errors. Error message text follows bellow:
ESP_Email_Attachments:43: error: redefinition of ‘SMTPSession smtp’
SMTPSession smtp;
^
C:\Users____\Documents\Arduino\sketch_nov18a\sketch_nov18a.ino:42:13: note: ‘SMTPSession smtp’ previously declared here
SMTPSession smtp;
^
C:\Users____\Documents\Arduino\sketch_nov18a\ESP_Email_Attachments.ino: In function ‘void setup()’:
ESP_Email_Attachments:48: error: redefinition of ‘void setup()’
void setup(){
^
C:\Users____\Documents\Arduino\sketch_nov18a\sketch_nov18a.ino:47:6: note: ‘void setup()’ previously defined here
void setup(){
^
C:\Users____\Documents\Arduino\sketch_nov18a\ESP_Email_Attachments.ino: In function ‘void loop()’:
ESP_Email_Attachments:146: error: redefinition of ‘void loop()’
void loop()
^
C:\Users____\Documents\Arduino\sketch_nov18a\sketch_nov18a.ino:145:6: note: ‘void loop()’ previously defined here
void loop() { }
^
C:\Users___\Documents\Arduino\sketch_nov18a\ESP_Email_Attachments.ino: In function ‘void smtpCallback(SMTP_Status)’:
ESP_Email_Attachments:151: error: redefinition of ‘void smtpCallback(SMTP_Status)’
void smtpCallback(SMTP_Status status){
^
C:\Users____\Documents\Arduino\sketch_nov18a\sketch_nov18a.ino:148:6: note: ‘void smtpCallback(SMTP_Status)’ previously defined here
void smtpCallback(SMTP_Status status){
^
Multiple libraries were found for “WiFi.h”
Used: C:\Users___\AppData\Local\Arduino15\packages\esp32\hardware\esp32\1.0.1\libraries\WiFi
Not used: C:\Program Files (x86)\Arduino\libraries\WiFi
Multiple libraries were found for “SD.h”
Used: C:\Users\loren\AppData\Local\Arduino15\packages\esp32\hardware\esp32\1.0.1\libraries\SD
Not used: C:\Program Files (x86)\Arduino\libraries\SD
exit status 1
redefinition of ‘SMTPSession smtp’
Hi.
It seems you didn’t copy the code correctly. Can you check it again?
I just tested that code and it is compiling just fine.
Regards,
Sara
Sara,
Thank you so much for your response. Yes, it works fine. Initially, I had been copying the code from the window within the tutorial. This time I copied from the “VIEW RAW CODE” option and it compiled OK. Could there be a slight difference between the two?
Hi.
No, the codes are the same.
You must have copied something twice. I recommend always copying the code from the VIEW RAW CODE option.
Regards,
Sara
Hi,
I just tried this code, which is working fine (ESP32).
A little note : Google mail does not provide the “Less Secure App” option anymore. Instead, you must create an App password. Same for Yahoo.
Just one question: I noticed the constant decrease of the Heap value.
Is there a way to prevent this to happen? If you leave the system unattended for a while, one could run out of memory.
I checked the library source code, but could not find anything related to this point.
Thanks,
Thierry
Thanks for sharing that.
I updated the tutorial to login with an app password.
I’m not sure what’s the answer to your question. Maybe it is better to ask the library’s developer?
Regards,
Sara
Sara & Rui,
This worked fine on a m5stamp-c3 (esp32).
Very good work.
Small is beautiful !!
Best regards
Cemal
Hello,
I am French man, be indulgent with my English!
I try to use your example with a SD card File (it run well with SPIFFS), where I logged data every minutes.
First I initialize a SD card:
if (!SD.begin(4))
{
cardOK_g= 0;
Serial.println(“Card failed, or not present je mets cardOK à 0”);
}
….
Then I just modify the line
att.file.storage_type = esp_mail_file_storage_type_flash;
By
att.file.storage_type = esp_mail_file_storage_type_sd;
I got the message :Sending attachments…
Peisey1.txt
did I forgot something?
Thank a lot
Gilles from Paris
Hi.
I’m not sure.
I also tried it with an SD card some time ago and wasn’t able to make it work. However, I don’t remember what was exactly my problem.
Regards,
Sara
Olá!
O código funciona perfeitamente, porem tem alguma forma para que a notificação de alerta seja envia para três e-mails diferentes?
Olá!
É possível enviar para mais deu um e-mail a notificação de alerta?
Hi, congratulations for your code…but i wanted know if is possible a sucess in ESP01 (8266)..
Hi.
Yes. It should work on an ESP-01. But, you’ll need to follow the next tutorial instead: https://randomnerdtutorials.com/esp8266-nodemcu-send-email-smtp-server-arduino/
Regards.
Sara
Thank you so much for updating this code to add 2-step-verification. My outdoor mailbox was very quiet lately and then I found out GMAIL didn’t support unsafe devices anymore since 30 May. You guys saved me from a lot of work. Thanks again!!
Very cool project you shared on that youtube link!
That looks great!
Thanks for great tutorial – it works perfectly but how to use it in a real-world sense? Sorry if this is dumb question but it would be more useful to me if the recipient email address was not hard coded. I pull the recipient address out of a cloud data store for my application. Is there a way to not hard code the to_address at compile time and send to the address my app has stored in a String or Char array?
Nevermind – String recipient_address “[email protected]” at runtime works great!
Good afternoon,
Is this being updated for the new google security requriements. I am getting an error:
< S: 534-5.7.9 Application-specific password required. Learn more at
< S: 534 5.7.9 https://support.google.com/mail/?p=InvalidSecondFactor n20-20020a05620a223400b006a6b564e9b8sm6067424qkh.4 – gsmtp
Error, authentication failed
Never mind figured it out. I would paste above the following section:
#define AUTHOR_PASSWORD “YOUR_EMAIL_PASS”
That’s where you put the app password you generated for overlogged newbs like me.