Bulk Email Generation with Dynamic Data Using Freemarker and domail

In today's fast-paced world, businesses often rely on automating tasks such as sending bulk emails. However, it is important to ensure that each recipient receives personalized content relevant to them. One effective way to do this is by integrating dynamic data into email templates using templating engines like Freemarker, which is supported by platforms like domail. This article will walk you through how to create dynamic tables using Freemarker and domail for sending customized emails based on specific data points, like invoices, to multiple recipients.

The Challenge: Dynamic Data for Each Recipient

Imagine you have two datasets:

• template_main.csv : Contains recipient email addresses and other general details.
• template_additional.csv : Contains specific invoice details such as item names, quantities, and prices for each recipient, which are linked by the email column.

The goal is to send personalized emails with a dynamically generated table showing each recipient's unique invoice details, calculated totals, and other related data points.

Create connection

After uploading the primary table, you can also upload an additional table and link them using a relationship or binding, such as the Email column. This connection allows the two datasets to work together seamlessly. By establishing this connection, users can leverage the data from both tables directly in their email templates, enabling dynamic content generation. This means that each recipient will receive a personalized version of the email, populated with values from the linked tables, such as item names, quantities, prices, and totals. This functionality simplifies the process of sending customized bulk emails, ensuring that every recipient gets relevant information specific to them.

Freemarker: The Templating Engine

Freemarker is a powerful templating language often used to generate dynamic content. It allows us to insert logic (such as loops and conditional statements) into HTML templates. Below is an example of how Freemarker can be utilized to calculate invoice totals and render a personalized table for each email recipient.

Sample Code Snippet Using Freemarker:

  <table style="border-collapse: collapse;" border="1">
    <tr>
      <td>Name</td>
      <td>Quantity</td>
      <td>Price</td>
    </tr>
    <#list template_additional as item>
    <tr>
      <td>${item.Name}</td>
      <td>${item.Quantity}</td>
      <td>${item.Price}</td>
    </tr>
    </#list>
    <tr>
      <td>Total:</td>
      <td>
        <#assign total = 0 />
        <#list template_additional as item>
          <#assign total = total + item.Quantity?eval />
        </#list>
        ${total}
      </td>
      <td>
        <#assign total_price = 0 />
        <#list template_additional as item>
          <#assign total_price = total_price + (item.Price?eval * item.Quantity?eval) />
        </#list>
        ${total_price?string("0.##")}
      </td>
    </tr>
  </table>    
  

In the example above, Freemarker performs the following:

• <#list template_additional as item>: Loops through each invoice item for the recipient, dynamically populating the table with the name, quantity, and price of each item.
• <#assign>: Assigns variables to calculate the total quantity and total price for the invoice.
• ${}: Inserts dynamic values into the template, such as the item name, total quantity, and total price.

This templating logic ensures that the email content remains unique to each recipient, making the process of bulk emailing both efficient and personalized.

Algorithm for Calculating Totals

Freemarker's power lies in its ability to handle logic directly within the template. Here’s a quick overview of the algorithm for calculating totals:

• Initialize Totals:
  • The algorithm starts by assigning the initial total of quantities and prices to zero.
  • For quantities: <#assign total = 0 />
  • For prices: <#assign total_price = 0 />
• Iterate Over Each Item:
  • For each item in the template_additional dataset, Freemarker extracts the quantity (item.Quantity) and price (item.Price), dynamically calculating the total as it iterates through the list.
• Display the Result:
  • The calculated totals are then displayed at the bottom of the table using ${total} for quantities and ${total_price?string("0.##")} for formatted prices (with two decimal places).

This method is both flexible and powerful, allowing the dynamic generation of personalized tables for each recipient based on their unique data.

Example of a Generated Email

An example of an email generated using this approach might look like this:

Name	Quantity	Price
Bulbasaur	4	3.50
Ivysaur	3	4.50
Venusaur	2	5.15
Charizard	2	15.00
Total:	11	67.80

This email contains a dynamically generated table of products with their quantities and prices, and the total is calculated automatically. Each recipient would receive an email with a unique table based on their specific invoice.

By combining Freemarker’s templating capabilities with domail’s bulk email features, businesses can automate the process of sending personalized, data-driven emails to large recipient lists, saving time and reducing errors.

Conclusion

Using Freemarker and domail together provides a robust solution for dynamically generating personalized emails with detailed tables. Whether you need to send invoices, product lists, or any other form of structured data, this combination offers flexibility and efficiency.