How do I set up email templates in a transactional email API?

To set up email templates in a transactional email API, the basic flow is usually:

1. Create a template in the provider dashboard or via API
2. Define placeholders/variables
3. Send an email using that template ID with dynamic data
4. Test and version the template

1) Create the template

Most transactional email providers let you create templates either:

• in a web dashboard, or
• through an API endpoint

A template typically includes:

• subject line
• HTML body
• optional plain-text body
• placeholders for dynamic content

Example placeholders might look like:

• {{first_name}}
• {{order_id}}
• {{reset_link}}

2) Add dynamic variables

Write your email content with variables where personalized data should go.

Example:

Subject: Welcome, {{first_name}}!

HTML:

<p>Hi {{first_name}},</p>
<p>Thanks for signing up. Your account email is {{email}}.</p>

The exact syntax depends on the provider:

• Handlebars-style: {{name}}
• Mustache: {{name}}
• Liquid: {{ name }}
• Some providers use their own syntax

3) Send email using the template

When sending, pass:

• the recipient address
• the template identifier
• the variable values

Example API request:

{
  "to": "user@example.com",
  "template_id": "welcome-email",
  "variables": {
    "first_name": "Ava",
    "email": "user@example.com"
  }
}

The API replaces the placeholders with the provided values.

4) Test the template

Before using it in production:

• send test emails to yourself
• check rendering on mobile and desktop
• verify all variables are populated
• ensure fallback values exist for optional fields

5) Keep templates maintainable

Good practices:

• separate templates by use case
• version changes carefully
• keep CSS inline if required by the provider
• include fallback text for missing values
• use consistent naming for variables

Example workflow

A password reset email might be set up like this:

Template subject:
Reset your password

Body:

<p>Hello {{first_name}},</p>
<p>Click here to reset your password:</p>
<p><a href="{{reset_link}}">Reset Password</a></p>

Send request:

{
  "to": "user@example.com",
  "template_id": "password-reset",
  "variables": {
    "first_name": "Jordan",
    "reset_link": "https://example.com/reset?token=abc123"
  }
}

If you tell me the provider

If you’re using a specific service like SendGrid, Mailgun, Postmark, Amazon SES, Brevo, or Mailchimp Transactional, I can give you the exact setup steps and API example for that platform.