Example to send email using SendGrid API to multiple recipients

content.html

<h2>Hi!</h2>

<p>This is a very important email!</p>

<h3>Thank you!</h3>

mail.py

import os
from sendgrid import SendGridAPIClient
from sendgrid.helpers.mail import Mail

# Edit the following
RECIPIENTS_FILE = 'recipients.txt'
CONTENT_FILE = 'content.html'

SENDER = 'foo@bar.com'
SUBJECT = 'This is an interesting email!'

def read_recipient_emails(filename):
    with open(filename) as f:
        return [l.strip() for l in f.readlines()]

def read_content(filename):
    with open(filename) as f:
        return f.read()

def send_email(recipient, subject, content):
    print('sending email to {}'.format(recipient))
    message = Mail(
        from_email=SENDER,
        to_emails=recipient,
        subject=subject,
        html_content=content
    )

    try:
        sg = SendGridAPIClient(os.environ.get('SENDGRID_API_KEY'))
        response = sg.send(message)
        print(response.status_code)
        print(response.body)
        print(response.headers)
    except Exception as e:
        print(e.message)


def main():
    recipients = read_recipient_emails(RECIPIENTS_FILE)
    content = read_content(CONTENT_FILE)

    for recipient in recipients:
        send_email(recipient, SUBJECT, content)

if __name__ == "__main__":
    main()

recipients.txt

baz@quu.com