How do I use one API for email and in-app alerts?

Use a single notification API and make the channel a parameter.

Common pattern

Send one request like:

POST /notifications
{
  "user_id": "123",
  "type": "order_shipped",
  "channels": ["email", "in_app"],
  "title": "Your order shipped",
  "message": "Your package is on the way.",
  "data": {
    "order_id": "A1001"
  }
}

How it works

• One endpoint handles all notifications.
• channels tells the system where to deliver:
  • email
  • in_app
  • or both
• The backend routes the same notification content to the right delivery service.

Recommended structure

1. Notification API
   • Accepts one payload
   • Validates recipient, template, and channels
2. Channel adapters
   • Email adapter sends via SMTP/SendGrid/Mailgun
   • In-app adapter stores alert in your database / websocket stream
3. Template system
   • One logical notification type
   • Channel-specific formatting if needed

Example backend flow

• API receives request
• Creates a notification record
• Queues jobs for each channel
• Email worker sends email
• In-app worker creates unread alert for user

Good design tips

• Keep the notification event separate from the delivery channel
• Use templates per channel if formatting differs
• Add preferences so users can opt out of email but keep in-app alerts
• Track delivery status per channel

If you want, I can show:

• a REST API design
• a database schema
• or an example in Node.js / Python / Java