How to send an email with Python

In today’s digital age, automating tasks is a highly valued skill. One common automation task is sending emails programmatically. Python, with its clear syntax and extensive libraries, makes sending emails a straightforward process. This article will guide you through the steps of how to send an email with Python, covering everything from setting up your environment to crafting and sending your first email. We’ll explore the necessary modules, authentication methods, and best practices to ensure your emails are delivered successfully. By the end of this guide, you’ll have a solid understanding of how to leverage Python to automate your email communications, saving you time and effort. Python’s simplicity allows you to integrate email functionality into various applications, from simple notification scripts to complex marketing automation systems.

Setting Up Your Python Environment for Email Sending

Before you start sending emails with Python, you need to ensure you have the necessary libraries installed and configured. The primary library we’ll be using is smtplib, which provides an SMTP (Simple Mail Transfer Protocol) client session object that can be used to send mail to any internet machine with an SMTP or ESMTP listener daemon. In most cases, smtplib comes pre-installed with Python, but it’s always a good idea to verify. To send emails securely, we’ll also use the ssl module, which provides access to Transport Layer Security (TLS) and Secure Sockets Layer (SSL) encryption protocols. These protocols ensure that your email credentials and content are protected during transmission, preventing eavesdropping and tampering.

To get started, open your terminal or command prompt and check if smtplib is available by running python -c "import smtplib". If no errors occur, the library is installed. If you encounter an error, you may need to reinstall Python or ensure that the standard library is properly configured. Next, you’ll need to decide which email service provider you want to use. Popular options include Gmail, Outlook, and Yahoo Mail. Each provider has its own SMTP server address and port number, which you’ll need to configure in your Python script. For example, Gmail’s SMTP server is smtp.gmail.com and uses port 587 for TLS encryption or port 465 for SSL encryption. You can find the specific SMTP settings for your chosen provider on their respective support pages. Ensuring you have the correct settings is crucial for successful email delivery.

Finally, you may need to enable “less secure app access” in your email account settings if you’re using older email providers or if you’re not using OAuth 2.0 for authentication. However, it’s strongly recommended to use OAuth 2.0 for enhanced security. OAuth 2.0 involves creating an application in your email provider’s developer console and obtaining credentials to authenticate your Python script. This method is more secure because it doesn’t require you to expose your email password directly in your code. According to Google’s security documentation, OAuth 2.0 is the recommended authentication method for all applications accessing Google services. Learn more about Python and automation.

Crafting Your Email Message with Python

Once your environment is set up, the next step is to craft your email message. Python’s email module provides classes for creating and manipulating email messages. You can create plain text emails, HTML emails, or even emails with attachments. To create a simple plain text email, you can use the MIMEText class. This class takes the email body, the subtype (e.g., ‘plain’ for plain text), and the charset (e.g., ‘utf-8’ for Unicode encoding) as arguments. For example:

from email.mime.text import MIMEText message = MIMEText("This is the email body.", 'plain', 'utf-8')

To add headers to your email, such as the sender (From), recipient (To), and subject, you can set the corresponding attributes of the MIMEText object. For example:

message['From'] = "sender@example.com" message['To'] = "recipient@example.com" message['Subject'] = "Subject of the Email"

For more complex emails, such as those with HTML formatting or attachments, you’ll need to use the MIMEMultipart class. This class allows you to combine multiple parts into a single email message. You can add a plain text part and an HTML part to provide both text-based and visually rich content to your recipients. For example, to create an email with both plain text and HTML content:

from email.mime.multipart import MIMEMultipart from email.mime.text import MIMEText message = MIMEMultipart("alternative") message['From'] = "sender@example.com" message['To'] = "recipient@example.com" message['Subject'] = "Subject of the Email" text_part = MIMEText("This is the plain text part.", 'plain', 'utf-8') html_part = MIMEText("<p>This is the <strong>HTML</strong> part.</p>", 'html', 'utf-8') message.attach(text_part) message.attach(html_part)

When crafting your email, consider the following:

Use a clear and concise subject line to grab the recipient’s attention.
Personalize your email content to make it more engaging.
Ensure your email is properly formatted and easy to read on different devices.

Sending Your Email with Python and SMTP

Now that you have crafted your email message, the next step is to send it using Python’s smtplib module. The smtplib module provides an SMTP client session object that you can use to connect to an SMTP server, authenticate, and send your email. To send an email, you need to create an SMTP object, connect to the server, authenticate with your credentials, and then send the email using the sendmail() method. Here’s a step-by-step guide:

Create an SMTP object: smtp = smtplib.SMTP('smtp.example.com', 587)
Start TLS encryption (if required by your email provider): smtp.starttls()
Authenticate with your credentials: smtp.login("your_email@example.com", "your_password")
Send the email: smtp.sendmail("sender@example.com", "recipient@example.com", message.as_string())
Close the connection: smtp.quit()

Here’s a complete example of how to send an email with Python using Gmail’s SMTP server:

import smtplib, ssl from email.mime.text import MIMEText from email.mime.multipart import MIMEMultipart sender_email = "your_email@gmail.com" receiver_email = "recipient@example.com" password = "your_password" message = MIMEMultipart("alternative") message["From"] = sender_email message["To"] = receiver_email message["Subject"] = "Python Email Test" text = "This is a test email sent from Python." html = "<p>This is a test <strong>email</strong> sent from Python.</p>" part1 = MIMEText(text, "plain") part2 = MIMEText(html, "html") message.attach(part1) message.attach(part2) context = ssl.create_default_context() with smtplib.SMTP_SSL("smtp.gmail.com", 465, context=context) as server: server.login(sender_email, password) server.sendmail( sender_email, receiver_email, message.as_string() )

It’s crucial to handle exceptions when sending emails, such as connection errors, authentication failures, and server errors. Wrap your email sending code in a try...except block to catch these exceptions and handle them gracefully. This ensures that your script doesn’t crash and provides informative error messages to the user. According to a study by Litmus, 21% of emails never reach the inbox. Litmus offers tools to help improve email deliverability.

Featured Snippet: To send an email with Python, you’ll first need to set up your environment by installing the smtplib and ssl modules. Then, craft your email message using the email module, specifying the sender, recipient, subject, and body. Finally, use the smtplib module to connect to an SMTP server, authenticate with your credentials, and send the email. Remember to handle exceptions to ensure your script runs smoothly.

Best Practices and Troubleshooting

Sending emails programmatically can be tricky, and it’s essential to follow best practices to ensure your emails are delivered successfully and avoid being marked as spam. One of the most important best practices is to use a dedicated email sending service or transactional email provider for sending large volumes of emails. Services like SendGrid, Mailgun, and Amazon SES provide robust infrastructure and deliverability tools to help you manage your email sending reputation and ensure your emails reach the inbox. These services handle the complexities of email authentication, IP address management, and feedback loops with ISPs, allowing you to focus on your application logic.

Another best practice is to properly authenticate your emails using SPF (Sender Policy Framework), DKIM (DomainKeys Identified Mail), and DMARC (Domain-based Message Authentication, Reporting & Conformance) records. These DNS records verify that your email is authorized to be sent from your domain, reducing the chances of it being flagged as spam. SPF specifies which mail servers are allowed to send emails on behalf of your domain, DKIM adds a digital signature to your emails that can be verified by the recipient’s mail server, and DMARC provides instructions to recipient mail servers on how to handle emails that fail SPF and DKIM checks. Implementing these authentication methods significantly improves your email deliverability and protects your domain from spoofing. SendGrid’s SPF Documentation provides detailed guidance on setting up SPF records.

When troubleshooting email sending issues, start by checking your SMTP server settings and ensuring they are correct. Double-check your email credentials and make sure you have enabled “less secure app access” or configured OAuth 2.0 if required by your email provider. Also, examine the error messages you receive from the smtplib module, as they often provide valuable clues about the cause of the problem. Common error messages include SMTPAuthenticationError (incorrect username or password), SMTPServerDisconnected (connection to the server was lost), and SMTPRecipientsRefused (recipient address is invalid). Finally, check your spam folder to see if your emails are being delivered there, and if so, take steps to improve your email content and sending reputation.

Infographic here showing the email sending process with Python.

FAQ ---

**Q: Why are my emails going to spam?**: A: Emails often end up in spam due to factors like poor sender reputation, lack of proper authentication (SPF, DKIM, DMARC), or spam-like content. Ensure your email content is relevant, your sending IP isn't blacklisted, and that you've properly configured your DNS records.
**Q: How can I send HTML emails with Python?**: A: Use the `MIMEText` class with the `'html'` subtype to create an HTML email body. Then, attach this part to a `MIMEMultipart` object to create a complete HTML email.
**Q: Is it safe to include my password directly in my Python script?**: A: No, it's not safe. Avoid hardcoding your password directly in your script. Use environment variables or OAuth 2.0 for secure authentication.
**Q: What is SMTP?**: A: SMTP stands for Simple Mail Transfer Protocol. It's a protocol used for sending email messages between servers.

- Always use secure authentication methods like OAuth 2.0. - Monitor your email sending reputation regularly.

Learning how to send an email with Python opens up a world of automation possibilities. From sending personalized notifications to managing complex email campaigns, the skills you’ve gained here are invaluable. Remember to prioritize security, follow best practices for deliverability, and continuously refine your approach. Question & Answer :

This code works and sends me an email just fine:

import smtplib #SERVER = "localhost" FROM = '<a class="__cf_email__" data-cfemail="99f4f6f7ede0d9e9e0edf1f6f7b7faf6f4" href="/cdn-cgi/l/email-protection">[email protected]</a>' TO = ["<a class="__cf_email__" data-cfemail="690306072904100a060419080710470a0604" href="/cdn-cgi/l/email-protection">[email protected]</a>"] # must be a list SUBJECT = "Hello!" TEXT = "This message was sent with Python's smtplib." # Prepare actual message message = """\ From: %s To: %s Subject: %s %s """ % (FROM, ", ".join(TO), SUBJECT, TEXT) # Send the mail server = smtplib.SMTP('myserver') server.sendmail(FROM, TO, message) server.quit()

However if I try to wrap it in a function like this:

def sendMail(FROM,TO,SUBJECT,TEXT,SERVER): import smtplib """this is some test documentation in the function""" message = """\ From: %s To: %s Subject: %s %s """ % (FROM, ", ".join(TO), SUBJECT, TEXT) # Send the mail server = smtplib.SMTP(SERVER) server.sendmail(FROM, TO, message) server.quit()

and call it I get the following errors:

Traceback (most recent call last): File "C:/Python31/mailtest1.py", line 8, in <module> sendmail.sendMail(sender,recipients,subject,body,server) File "C:/Python31\sendmail.py", line 13, in sendMail server.sendmail(FROM, TO, message) File "C:\Python31\lib\smtplib.py", line 720, in sendmail self.rset() File "C:\Python31\lib\smtplib.py", line 444, in rset return self.docmd("rset") File "C:\Python31\lib\smtplib.py", line 368, in docmd return self.getreply() File "C:\Python31\lib\smtplib.py", line 345, in getreply raise SMTPServerDisconnected("Connection unexpectedly closed") smtplib.SMTPServerDisconnected: Connection unexpectedly closed

Can anyone help me understand why?

I recommend that you use the standard packages email and smtplib together to send email. Please look at the following example (reproduced from the Python documentation). Notice that if you follow this approach, the “simple” task is indeed simple, and the more complex tasks (like attaching binary objects or sending plain/HTML multipart messages) are accomplished very rapidly.

# Import smtplib for the actual sending function import smtplib # Import the email modules we'll need from email.mime.text import MIMEText # Open a plain text file for reading. For this example, assume that # the text file contains only ASCII characters. with open(textfile, 'rb') as fp: # Create a text/plain message msg = MIMEText(fp.read()) # me == the sender's email address # you == the recipient's email address msg['Subject'] = 'The contents of %s' % textfile msg['From'] = me msg['To'] = you # Send the message via our own SMTP server, but don't include the # envelope header. s = smtplib.SMTP('localhost') s.sendmail(me, [you], msg.as_string()) s.quit()

For sending email to multiple destinations, you can also follow the example in the Python documentation:

# Import smtplib for the actual sending function import smtplib # Here are the email package modules we'll need from email.mime.image import MIMEImage from email.mime.multipart import MIMEMultipart # Create the container (outer) email message. msg = MIMEMultipart() msg['Subject'] = 'Our family reunion' # me == the sender's email address # family = the list of all recipients' email addresses msg['From'] = me msg['To'] = ', '.join(family) msg.preamble = 'Our family reunion' # Assume we know that the image files are all in PNG format for file in pngfiles: # Open the files in binary mode. Let the MIMEImage class automatically # guess the specific image type. with open(file, 'rb') as fp: img = MIMEImage(fp.read()) msg.attach(img) # Send the email via our own SMTP server. s = smtplib.SMTP('localhost') s.sendmail(me, family, msg.as_string()) s.quit()

As you can see, the header To in the MIMEText object must be a string consisting of email addresses separated by commas. On the other hand, the second argument to the sendmail function must be a list of strings (each string is an email address).

So, if you have three email addresses: <a class="__cf_email__" data-cfemail="5f2f3a2d2c30316e1f3a273e322f333a713c3032" href="/cdn-cgi/l/email-protection">[email protected]</a>, <a class="__cf_email__" data-cfemail="86f6e3f4f5e9e8b4c6e3fee7ebf6eae3a8e5e9eb" href="/cdn-cgi/l/email-protection">[email protected]</a>, and <a class="__cf_email__" data-cfemail="cbbbaeb9b8a4a5f88baeb3aaa6bba7aee5a8a4a6" href="/cdn-cgi/l/email-protection">[email protected]</a>, you can do as follows (obvious sections omitted):

to = ["<a class="__cf_email__" data-cfemail="671702151408095627021f060a170b024904080a" href="/cdn-cgi/l/email-protection">[email protected]</a>", "<a class="__cf_email__" data-cfemail="dcacb9aeafb3b2ee9cb9a4bdb1acb0b9f2bfb3b1" href="/cdn-cgi/l/email-protection">[email protected]</a>", "<a class="__cf_email__" data-cfemail="9dedf8efeef2f3aeddf8e5fcf0edf1f8b3fef2f0" href="/cdn-cgi/l/email-protection">[email protected]</a>"] msg['To'] = ",".join(to) s.sendmail(me, to, msg.as_string())

the ",".join(to) part makes a single string out of the list, separated by commas.

From your questions I gather that you have not gone through the Python tutorial - it is a MUST if you want to get anywhere in Python - the documentation is mostly excellent for the standard library.