Send mail with attachment from your Gmail account using Python

In this article, we will see how we can send email with attachments using Python. To send mail, we do not need any external library. There is a module called SMTPlib, which comes with Python. It uses SMTP (Simple Mail Transfer Protocol) to send the mail. It creates SMTP client session objects for mailing.

SMTP needs valid source and destination email ids, and port numbers. The port number varies for different sites. As an example, for google the port is 587.

At first we need to import the module to send mail.

import smtplib

Here we are also using the MIME (Multipurpose Internet Mail Extension) module to make it more flexible. Using MIME header, we can store the sender and receiver information and some other details. MIME is also needed to set the attachment with the mail.

We are using Google's Gmail service to send mail. So we need some settings (if required) for google's security purposes. If those settings are not set up, then the following code may not work, if the google doesnot support the access from third-party app.

To allow the access, we need to set 'Less Secure App Access' settings in the google account. If the two step verification is on, we cannot use the less secure access.

To complete this setup, go to the Google's Admin Console, and search for the Less Secure App setup.

Send Mail

Steps to Send Mail with attachments using SMTP (smtplib)

  • Create MIME
  • Add sender, receiver address into the MIME
  • Add the mail title into the MIME
  • Attach the body into the MIME
  • Open the file as binary mode, which is going to be attached with the mail
  • Read the byte stream and encode the attachment using base64 encoding scheme.
  • Add header for the attachments
  • Start the SMTP session with valid port number with proper security features.
  • Login to the system.
  • Send mail and exit

Example code

import smtplib
from email.mime.multipart import MIMEMultipart
from email.mime.text import MIMEText
from email.mime.base import MIMEBase
from email import encoders
mail_content = '''Hello,
This is a test mail.
In this mail we are sending some attachments.
The mail is sent using Python SMTP library.
Thank You
#The mail addresses and password
sender_address = ''
sender_pass = 'xxxxxxxx'
receiver_address = ''
#Setup the MIME
message = MIMEMultipart()
message['From'] = sender_address
message['To'] = receiver_address
message['Subject'] = 'A test mail sent by Python. It has an attachment.'
#The subject line
#The body and the attachments for the mail
message.attach(MIMEText(mail_content, 'plain'))
attach_file_name = 'TP_python_prev.pdf'
attach_file = open(attach_file_name, 'rb') # Open the file as binary mode
payload = MIMEBase('application', 'octate-stream')
encoders.encode_base64(payload) #encode the attachment
#add payload header with filename
payload.add_header('Content-Decomposition', 'attachment', filename=attach_file_name)
#Create SMTP session for sending the mail
session = smtplib.SMTP('', 587) #use gmail with port
session.starttls() #enable security
session.login(sender_address, sender_pass) #login with mail_id and password
text = message.as_string()
session.sendmail(sender_address, receiver_address, text)
print('Mail Sent')


D:\Python TP\Python 450\linux>python
Mail Sent

Test Mail
Samual Sam
Samual Sam

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