Email Service Integration
Table of Contents
Overview
Build comprehensive email systems with SMTP integration, third-party email providers (SendGrid, Mailgun, AWS SES), HTML templates, email validation, retry mechanisms, and proper error handling.
When to Use
- Sending transactional emails
- Implementing welcome/confirmation emails
- Creating password reset flows
- Sending notification emails
- Building email templates
- Managing bulk email campaigns
Quick Start
Minimal working example:
# config.py
import os
class EmailConfig:
MAIL_SERVER = os.getenv('MAIL_SERVER', 'smtp.gmail.com')
MAIL_PORT = int(os.getenv('MAIL_PORT', 587))
MAIL_USE_TLS = os.getenv('MAIL_USE_TLS', True)
MAIL_USERNAME = os.getenv('MAIL_USERNAME')
MAIL_PASSWORD = os.getenv('MAIL_PASSWORD')
MAIL_DEFAULT_SENDER = os.getenv('MAIL_DEFAULT_SENDER', 'noreply@example.com')
# email_service.py
from flask_mail import Mail, Message
from flask import render_template_string
import logging
from datetime import datetime
import smtplib
from email.mime.text import MIMEText
from email.mime.multipart import MIMEMultipart
logger = logging.getLogger(__name__)
mail = Mail()
class EmailService:
def __init__(self, app=None):
// ... (see reference guides for full implementation)Reference Guides
Detailed implementations in the references/ directory:
| Guide | Contents |
|---|---|
| Python/Flask with SMTP | Python/Flask with SMTP |
| Node.js with SendGrid | Node.js with SendGrid |
| Email Templates with Mjml | Email Templates with Mjml |
| FastAPI Email with Background Tasks | FastAPI Email with Background Tasks |
| Email Validation and Verification | Email Validation and Verification |
Best Practices
✅ DO
- Use transactional email providers for reliability
- Implement email templates for consistency
- Add unsubscribe links (required by law)
- Use background tasks for email sending
- Implement proper error handling and retries
- Validate email addresses before sending
- Add rate limiting to prevent abuse
- Monitor email delivery and bounces
- Use SMTP authentication
- Test emails in development environment
❌ DON'T
- Send emails synchronously in request handlers
- Store passwords in code
- Send sensitive information in emails
- Use generic email addresses for sensitive operations
- Skip email validation
- Ignore bounce and complaint notifications
- Use HTML email with inline styles excessively
- Forget to handle failed email deliveries
- Send emails without proper templates
- Store email addresses without consent