Background

Sending emails is one of the most common functionalities in the modern world. This article is not about how email works under the hood, but how you can easily send an email using a python script.

Why use Python to send an email when you can use Gmail?

• when you know how to send an email with python, you can automate a lot of boring stuff
• you can also integrate the email feature with your other applications
• send out your newsletter for free

and the use cases are endless.

Requirements

To follow this tutorial you must have python 3.6 + installed in your system. At the time I am writing this article, I recommend using python 3.9.3 (the latest stable version).

Open your terminal (also called command prompt in windows), and type python --version, and you should get something like this.

❯ python --version
Python 3.9.0+

You also need to have an email server running. I will not delve deep into behind-the-scenes technology in this article. If you have a Gmail account (or any other email provider), then you are good to go.

Introducing smtplib

The Simple Mail Transfer Protocol is an internet standard communication protocol for electronic mail transmission. Mail servers and other message transfer agents use SMTP to send and receive mail messages.

Python provides smptplib which is a library used to send mail to any Internet machine with an SMTP or ESMTP listener daemon.

As smtplib is a part of the python standard library, you don't have to install anything to start using it.

Python offers another standard library called email for basic email-related operations.

Sending a simple email

So first of all let's import smptplib which has already done all the heavy lifting for us.

from smtplib import SMTP

Now we need to define some important variables to get started.

HOST = 'smtp.gmail.com' 
# use the smtp server address of your mail provider


PORT = 587 
# this if for TLS, 
# will discuss more about this in a future article

SENDER = 'youremail@gmail.com'

PASSWORD = 'your12434(893**!@password' 
# don't share this script with anyone 🤫
# for building real applications
# always read secrets from environment variables

Now that we have defined the variables required, let's move on to start a connection with the mail server and log in with our credentials.

server = SMTP(host=HOST, port=PORT)
# create an SMTP server object

server.connect(host=HOST, port=PORT)
# connect 


server.ehlo()
# extended hello; like saying hello

server.starttls()
server.ehlo()

server.login(user=SENDER, password=PASSWORD)
# login with your credentials

All the shitty stuff is now over, it's time to finally send the email.

Before we do that, we need to have the email address of the recipient and also the message we want to send them.

RECIPIENT = 'email@example.com'

MESSAGE = '''
Hi! How are you?

This is my first email sent from Python.

Hope to see you soon.
'''

Finally, one more line to send the email to the destination.

server.sendmail(SENDER,RECIPIENT,MESSAGE)

And that's it, we are done. 😀

Reading the tutorial passively will do you no good. Write down the script in a file called send.py and run it.

❯ python send.py

If everything went right, then there will be no output in the terminal, and you will see the email sitting right in the recipient's inbox.

In the upcoming articles of this series, we will make some enhancements to the script, so that we can send rich text emails and also attach files with our email.