Flask-Mail is a Flask extension for sending emails. It integrates easily with Flask applications. This guide will show you how to install and use it.

Prerequisites

Before installing Flask-Mail, ensure you have Python and Flask installed. If not, install them first.

You can check Python installation with:

python --version

For Flask, check our other guides like How to Install PyNaCl in Python for related setups.

Install Flask-Mail

Use pip to install Flask-Mail. Run this command:

pip install Flask-Mail

This will download and install the latest version. Verify the installation with:

pip show Flask-Mail

Basic Flask-Mail Setup

Here's a simple Flask application with Flask-Mail configured:

from flask import Flask
from flask_mail import Mail, Message

app = Flask(__name__)

# Configure mail
app.config['MAIL_SERVER'] = 'smtp.example.com'
app.config['MAIL_PORT'] = 587
app.config['MAIL_USE_TLS'] = True
app.config['MAIL_USERNAME'] = 'your-email@example.com'
app.config['MAIL_PASSWORD'] = 'your-password'

mail = Mail(app)

@app.route('/')
def send_mail():
    msg = Message('Hello', sender='your-email@example.com', recipients=['recipient@example.com'])
    msg.body = "This is a test email from Flask-Mail"
    mail.send(msg)
    return "Email sent!"

if __name__ == '__main__':
    app.run(debug=True)

The Message class creates an email. The mail.send method sends it.

Configuration Options

Flask-Mail supports several configuration options:

• MAIL_SERVER: SMTP server address
• MAIL_PORT: SMTP server port
• MAIL_USE_TLS: Enable TLS security
• MAIL_USERNAME: Your email username
• MAIL_PASSWORD: Your email password

Sending HTML Emails

You can send HTML emails by setting the html attribute:

msg = Message('Hello', sender='your-email@example.com', recipients=['recipient@example.com'])
msg.html = "
Welcome
This is HTML content
"
mail.send(msg)

Adding Attachments

To add attachments, use the attach method:

with app.open_resource("document.pdf") as fp:
    msg.attach("document.pdf", "application/pdf", fp.read())

Error Handling

Always handle email sending errors:

try:
    mail.send(msg)
except Exception as e:
    print(f"Error sending email: {e}")

Testing with Python's SMTP Server

For testing, use Python's built-in SMTP server:

python -m smtpd -n -c DebuggingServer localhost:1025

Then configure Flask-Mail to use this server:

app.config['MAIL_SERVER'] = 'localhost'
app.config['MAIL_PORT'] = 1025

Conclusion

Flask-Mail makes email sending in Flask applications easy. With proper configuration, you can send both text and HTML emails with attachments.

For more Python guides, check our articles like Install PyCryptodome in Python or How to Install dnspython.