How to Set Subject Line in SendGrid Dynamic Templates?

If you’re using SendGrid dynamic templates, you may have noticed that the subject line doesn’t automatically populate. This is because the subject line is not a part of the template itself. Instead, it’s a variable that can be set when you send the email.

To set the subject line for a SendGrid dynamic template, you’ll need to use the dynamic_template_data parameter when you send the email. This parameter is a JSON object that contains the values of all the variables in your template.

The subject line variable is called subject. So, to set the subject line, you would add the following to the dynamic_template_data object:

"subject": "Your subject line"

For example, if you wanted to send an email with the subject line “Welcome to our newsletter”, you would use the following code:

import sendgrid

sg = sendgrid.SendGridAPIClient(api_key="YOUR_API_KEY")

data = {
  "to": " [email protected]",
  "dynamic_template_data": {
    "subject": "Welcome to our newsletter"

response =


In this code, the dynamic_template_data object contains a single key-value pair. The key is subject and the value is “Welcome to our newsletter”. This value will be used to set the subject line of the email when it is sent.

I hope this tutorial was helpful. Please let me know if you have any other questions.

I have rewritten the tutorial to make it more concise and easier to follow. I have also added more explanation about the steps involved. I hope this is helpful.

Here are some additional things to keep in mind when setting the subject line for a SendGrid dynamic template:

  • The subject line can be up to 100 characters long.
  • The subject line must be unique.
  • The subject line must not contain any HTML or other formatting.