How do I add email templates to my product?

To add email templates to your product, you typically need 4 pieces:

1. A template format
2. A place to store templates
3. A rendering system to fill in variables
4. An email-sending service

Here’s a practical way to build it.

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1) Decide what kind of templates you need

Most products need a few email types, such as:

• Welcome email
• Password reset
• Invoice receipt
• Notification alerts
• Marketing campaigns

For each template, define:

• Subject
• Body
• Variables like {{first_name}}, {{reset_link}}
• HTML and/or plain text version

Example:

Subject: Reset your password

Hi {{first_name}},

Click here to reset your password:
{{reset_link}}

If you didn’t request this, ignore this email.

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2) Choose a template engine

You’ll want placeholder substitution and conditional logic. Common options:

• Handlebars
• Liquid
• Mustache
• Jinja2 (Python)
• ERB (Ruby)

A good rule:

• Use a simple templating language if non-developers will edit templates
• Use full code-based templates if only engineers will manage them

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3) Store templates somewhere

You have a few options:

Option A: In your codebase

Best if templates change rarely.

• Easy to version control
• Simple deployment
• Harder for non-technical users to edit

Example:

• emails/welcome.html
• emails/welcome.txt

Option B: In a database

Best if templates need to be editable in-app.

Store fields like:

• name
• subject
• html_body
• text_body
• variables
• locale
• updated_at

Option C: In an external provider

Use tools like:

• Postmark
• SendGrid
• Mailgun
• AWS SES
• Customer.io
• Braze

These often support template management, rendering, and analytics.

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4) Render the template with data

When sending an email, pass in the data needed for placeholders.

Example data:

{
  "first_name": "Ava",
  "reset_link": "https://example.com/reset?token=abc123"
}

Rendered output:

Hi Ava,

Click here to reset your password:
https://example.com/reset?token=abc123

Make sure to:

• Validate required variables
• Provide defaults for optional ones
• Escape user input in HTML templates to prevent injection

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5) Send via an email provider

Don’t send email directly from your app server if you can avoid it. Use a provider:

• Resend
• SendGrid
• Postmark
• Mailgun
• AWS SES

Why:

• Better deliverability
• Bounce handling
• Spam complaints tracking
• Retry logic
• Dedicated APIs

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6) Add preview and testing

Useful product features:

• Preview template with sample data
• Send test email
• Validate required variables
• Template version history
• A/B testing for marketing emails
• Localization for different languages

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7) Build a simple architecture

A common setup:

• Admin UI for editing templates
• Template storage in DB or provider
• Renderer service to substitute variables
• Mailer service to send the final email
• Queue/worker for asynchronous sending

Flow:

1. User triggers event
2. Your app selects the right template
3. Template is rendered with data
4. Email is sent through provider
5. Delivery/bounce events are logged

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8) Example implementation approach

If you want a simple internal solution

• Store templates in your database
• Use a templating engine like Handlebars/Liquid
• Send via Postmark/Resend/SendGrid
• Build a basic admin screen for editing templates

If you want to move fast

• Use your email provider’s built-in templates
• Keep only template IDs in your product
• Render and send through their API

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9) Important best practices

• Keep transactional and marketing emails separate
• Always include:
  • company name
  • reply-to info
  • unsubscribe link for marketing emails
• Ensure mobile-friendly HTML
• Test across clients: Gmail, Outlook, Apple Mail
• Log every send with template name/version
• Handle missing variables gracefully
• Support multi-language templates if needed

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10) Minimal data model example

templates
- id
- name
- subject
- html_body
- text_body
- locale
- type
- created_at
- updated_at

And a send log:

email_logs
- id
- template_id
- recipient
- status
- provider_message_id
- sent_at
- error

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Recommended MVP path

If you’re just starting:

1. Pick one email provider
2. Use Handlebars or Liquid
3. Store templates in your database
4. Add a preview/test send feature
5. Send emails through a background job queue

That gives you flexibility without too much complexity.

If you want, I can also give you:

• a sample database schema
• a Node/Python/Ruby implementation
• or a recommended architecture for SaaS products