Sending Bulk Emails - Step by Step

Author: Shaurya Sharma

This guide walks you through sending bulk emails using the Email Service.

Prerequisites

1. Run the Flask Server

   • Make sure you have installed all required Python packages (e.g., Flask, pymongo, brevo-python, jinja2, requests, python-dotenv, premailer).
   • Ensure you have a proper .env file containing MONGODB_URI, MONGODB_DB_EMAIL_SERVICE, BREVO_API_KEY, BREVO_SENDER_EMAIL, and BREVO_SENDER_NAME.
   • Start the server, typically with:

     python app.py
   • The server should be running on the configured port (default is 5001 in the code).

2. Confirm Your Topic Setup

   • Before sending an email, you need a valid topic in your database (topics collection).
   • Each topic typically references a template.
   • If your topic supports sub-options (e.g., countries), ensure corresponding reports documents exist.

3. Test the API

   • You can use cURL, Postman, or any other REST client to interact with the endpoints.

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Sending Bulk Emails

Use the bulk endpoint to send emails to multiple subscribers at once, typically used for daily or weekly distributions.

Step 1: Prepare the Request

• Endpoint: /send-bulk-emails
• Method: POST

Step 2: Craft the JSON Body

The exact format depends on your design, but a common example is:

{
  "topic_id": "64a888c0aaaabbbbccccddd1"
}

The service will look up all subscriptions for the given topic_id, gather those subscriber emails, then send out an email to each of them.

Step 3: Send the Request

Using cURL as an example:

curl -X POST \
  http://localhost:5001/send-bulk-emails \
  -H "Content-Type: application/json" \
  -d '{
    "topic_id": "64a888c0aaaabbbbccccddd1"
  }'

Step 4: Check the Response

A successful bulk send typically returns:

{
  "message": "Bulk email sending started",
  "report_id": "64a888c0aaaabbbbccccmmm4"
}

If errors occur partway through sending, the service may continue for other recipients or halt, depending on how error handling is implemented.

Step 5: Verify the Bulk Delivery

• Each email is typically logged in the database (e.g., email_reports collection) with a status of "success" or "failed".
• Confirm that multiple recipients have indeed received the email.

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Troubleshooting

• Topic or Template Not Found: Ensure topic_id is valid and that the topic references an existing template (if required).
• PDF Links Failing: Verify the PDF URLs are correct and publicly accessible.
• Email Not Delivered: Double-check your Brevo API Key, sender email, and that your domain is verified in Brevo.
• Server Errors (500): Inspect the Flask logs or the console output for Python traceback details.