> For the complete documentation index, see [llms.txt](https://docs.osmosworks.com/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.osmosworks.com/business-modules/notifications.md).

# Notifications

This module covers how Osmos sends emails and other asynchronous notifications.

## Outbox pattern

Osmos uses the outbox pattern to ensure notifications are sent reliably without blocking the main transaction. When the application needs to send a notification, it writes an `OutboxEvent` to the database and commits. A background scheduler processes pending events asynchronously.

```mermaid
sequenceDiagram
    autonumber
    participant App as Service Layer
    participant DB as PostgreSQL
    participant Worker as OutboxProcessingJob (Scheduled 2s)
    participant Resend as Resend Email API

    Note over App,DB: ACID Transaction
    App->>DB: INSERT / UPDATE Business Entity (e.g. Member invited)
    App->>DB: INSERT OutboxEvent (status: PENDING, availableAt: NOW)
    App->>DB: COMMIT Transaction

    Note over Worker,Resend: Asynchronous Reliable Processing
    Worker->>DB: SELECT PENDING events WHERE availableAt <= NOW (Batch: 20)
    Worker->>DB: UPDATE status = PROCESSING (Optimistic Lock)
    Worker->>Resend: Send email using template (e.g. re_staff_invite)
    
    alt Email delivered successfully
        Worker->>DB: UPDATE status = COMPLETED
    else Network failure / API Error
        Worker->>DB: UPDATE status = PENDING, attempts++, availableAt = NOW + exponentialBackoff
    else Max retries exceeded (3 attempts)
        Worker->>DB: UPDATE status = FAILED
    end
```

## Outbox event lifecycle

* `PENDING` — waiting to be processed.
* `PROCESSING` — currently being handled.
* `COMPLETED` — successfully processed.
* `FAILED` — failed after the maximum number of retries.

## Processing

The `OutboxProcessingJob` runs at a configured interval (default 2 seconds) and processes batches of pending events (default 20). It:

1. Selects pending events whose `availableAt` time has passed.
2. Marks them as `PROCESSING` with optimistic locking.
3. Dispatches them to the appropriate handler.
4. Marks them `COMPLETED` or schedules a retry with exponential backoff.

A separate recovery task resets events that have been stuck in `PROCESSING` for longer than the timeout. A cleanup task removes completed events older than the configured retention.

## Retry policy

* Maximum attempts: 3
* Initial delay: 10 seconds
* Maximum delay: 1 hour

## Email provider

Email notifications are sent through Resend. The backend stores Resend API configuration and template IDs in `application.yml`.

## Notification templates

Configured templates include:

* `re_org_verify` — organization onboarding verification.
* `re_staff_invite` — staff invitation.
* `re_password_reset` — password reset.
* `re_customer_setup` — customer account setup.
* `re_payment_succeeded` / `re_payment_failed` — payment results.
* `re_customer_paid` — customer payment confirmation.
* `re_sub_activated` / `re_sub_receipt` / `re_sub_failed` / `re_sub_grace` / `re_sub_downgraded` / `re_sub_changed` / `re_sub_canceled` — subscription lifecycle.
* `re_tier_warning` / `re_tier_blocked` — tier limit notifications.

## Manual retry

Platform or tenant administrators can retry a failed outbox event:

`POST /api/v1/admin/outbox/{eventId}/retry`

## Configuration

| Setting                              | Default               | Description                       |
| ------------------------------------ | --------------------- | --------------------------------- |
| `OUTBOX_PROCESSING_ENABLED`          | `true`                | Enable outbox processing.         |
| `OUTBOX_PROCESSING_INTERVAL_MS`      | 2000                  | Interval between processing runs. |
| `OUTBOX_PROCESSING_BATCH_SIZE`       | 20                    | Events processed per run.         |
| `OUTBOX_RETRY_MAX_ATTEMPTS`          | 3                     | Maximum retry attempts.           |
| `OUTBOX_RETRY_INITIAL_DELAY_SECONDS` | 10                    | Initial retry delay.              |
| `OUTBOX_RETRY_MAX_DELAY_SECONDS`     | 3600                  | Maximum retry delay.              |
| `RESEND_API_KEY`                     | test key              | Resend API key.                   |
| `RESEND_FROM_EMAIL`                  | `support@example.com` | From address.                     |

## Needs clarification

* The exact mapping of template IDs to Resend template names in the live account is configuration-dependent.
* SMS, push, and in-app notification channels are not implemented in the current codebase.


---

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