email template api dynamic variables

When people say “email template API dynamic variables”, they usually mean a system where you store an email template with placeholders, then fill those placeholders with real data when sending.

Example template

Hello {{first_name}},

Your order #{{order_id}} has been shipped.
Track it here: {{tracking_url}}

Example API payload

{
  "template_id": "order_shipped",
  "to": "customer@example.com",
  "variables": {
    "first_name": "Jane",
    "order_id": "12345",
    "tracking_url": "https://track.example.com/12345"
  }
}

How it works

1. Template contains placeholders like {{first_name}}
2. API request sends the values in a variables object
3. The service replaces placeholders with actual values
4. The final email is sent

Common placeholder formats

• {{name}}
• ${name}
• [[name]]

Tips

• Keep variable names consistent between template and API payload
• Provide defaults for missing values if possible
• Validate required variables before sending
• Escape HTML content if variables are inserted into HTML emails

Simple API design

Request

POST /send-email
Content-Type: application/json

{
  "template_id": "welcome_email",
  "to": "user@example.com",
  "variables": {
    "name": "John",
    "signup_date": "2026-10-05"
  }
}

Response

{
  "success": true,
  "message": "Email sent"
}

If you want, I can also give you:

• a Node.js example
• a Python example
• a database schema for email templates
• or a dynamic template syntax using Handlebars/Mustache