notification API with webhooks and logs

Here’s a practical design for a Notification API with webhooks and logs.

Core idea

The API lets your app:

1. Create notifications (email, SMS, push, in-app, etc.)
2. Register webhooks so external systems get event callbacks
3. Track delivery attempts and logs for auditing/debugging

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Main resources

1) Notifications

Represents a message/event to be delivered.

Fields

• id
• type — email | sms | push | webhook | in_app
• recipient
• title
• body
• status — queued | processing | sent | delivered | failed | canceled
• metadata
• created_at
• updated_at

2) Webhooks

A subscribed endpoint that receives notification events.

Fields

• id
• url
• events — e.g. notification.sent, notification.failed
• secret
• status — active | disabled
• created_at

3) Logs

Audit trail of events and delivery attempts.

Fields

• id
• notification_id
• event_type
• message
• attempt
• request
• response
• status
• created_at

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Suggested endpoints

Notifications

Create notification

POST /v1/notifications

{
  "type": "email",
  "recipient": "user@example.com",
  "title": "Welcome",
  "body": "Thanks for signing up!",
  "metadata": {
    "user_id": "123"
  }
}

Response

{
  "id": "ntf_123",
  "status": "queued",
  "created_at": "2026-10-14T12:00:00Z"
}

Get notification

GET /v1/notifications/{id}

List notifications

GET /v1/notifications?status=failed&type=email

Cancel notification

DELETE /v1/notifications/{id}

---

Webhooks

Create webhook

POST /v1/webhooks

{
  "url": "https://example.com/webhooks/notifications",
  "events": ["notification.sent", "notification.failed"]
}

List webhooks

GET /v1/webhooks

Update webhook

PATCH /v1/webhooks/{id}

Delete webhook

DELETE /v1/webhooks/{id}

Test webhook

POST /v1/webhooks/{id}/test

---

Logs

List notification logs

GET /v1/notifications/{id}/logs

Global logs

GET /v1/logs?event_type=notification.failed

Get specific log entry

GET /v1/logs/{id}

---

Webhook event payload example

When a notification is sent:

{
  "id": "evt_456",
  "type": "notification.sent",
  "created_at": "2026-10-14T12:01:00Z",
  "data": {
    "notification_id": "ntf_123",
    "recipient": "user@example.com",
    "channel": "email",
    "status": "sent"
  }
}

---

Webhook delivery best practices

• Sign payloads with an HMAC secret
• Retry failed deliveries with exponential backoff
• Include event_id for idempotency
• Return logs for every attempt
• Allow webhook filtering by event type

---

Logging strategy

Store:

• Request payload
• Response status/body
• Retry count
• Timing/latency
• Error message
• Delivery destination

Example log entry:

{
  "id": "log_789",
  "notification_id": "ntf_123",
  "event_type": "notification.failed",
  "attempt": 2,
  "status": "failed",
  "message": "SMTP server timeout",
  "created_at": "2026-10-14T12:02:00Z"
}

---

Minimal data model

notifications

• id (PK)
• type
• recipient
• title
• body
• status
• metadata (JSON)
• created_at
• updated_at

webhooks

• id (PK)
• url
• events (JSON array)
• secret
• status
• created_at
• updated_at

logs

• id (PK)
• notification_id (FK)
• event_type
• attempt
• request_body
• response_code
• response_body
• status
• created_at

---

If you want to implement it

A solid stack could be:

• API: FastAPI / Express / NestJS / Django REST
• Queue: Redis + BullMQ / RabbitMQ / SQS
• DB: PostgreSQL
• Webhook delivery: background workers
• Logs: DB table + centralized logging (ELK, Datadog, OpenTelemetry)

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If you want, I can turn this into:

1. a full OpenAPI spec,
2. a database schema, or
3. working code in FastAPI / Express / NestJS.