I'm building event-driven notifications for account and billing updates

Great use case. Event-driven notifications are a strong fit for account and billing updates because they let you react consistently to changes across your system without tightly coupling everything together.

A solid approach is:

1. Define domain events

Examples:

• AccountCreated
• AccountEmailUpdated
• PaymentMethodAdded
• InvoiceGenerated
• PaymentSucceeded
• PaymentFailed
• SubscriptionCanceled
• BillingAddressChanged

2. Emit events from the source of truth

When the account/billing state changes, publish an event from the service that owns that data. Keep the event payload focused on what consumers need, such as:

• account_id
• user_id
• event_type
• timestamps
• relevant changed fields
• correlation/request ID

3. Build notification consumers

Separate consumers can subscribe to those events and decide what to send:

• Email notifications
• SMS/push alerts
• Internal audit logs
• Support tickets
• Webhooks to customers

4. Make delivery reliable

For billing and account updates, reliability matters:

• Use an outbox pattern or transactional event publishing
• Make consumers idempotent
• Include event IDs for deduplication
• Retry with backoff
• Send failed messages to a dead-letter queue

5. Separate “event” from “notification”

Not every event should produce a user notification. For example:

• InvoiceGenerated might notify the billing contact
• SubscriptionRenewed might only go to email
• BillingAddressChanged might create an audit record but no customer-facing alert

6. Add templates and routing rules

Use a notification service that maps event types to:

• templates
• channels
• recipients
• localization

Example:

• PaymentFailed → email + push to primary account holder
• InvoiceGenerated → email to billing contact
• AccountPasswordChanged → email to user + security log

7. Track notification state

Store:

• event ID
• recipient
• channel
• delivery status
• retry count
• sent timestamp

This helps with observability and support.

If you want, I can help you design:

1. an event schema for account/billing notifications,
2. a system architecture for producer/consumer flow, or
3. example implementation code in your stack.