Channels

The Notification Service supports seven delivery channels. Each channel implements the NotificationChannel interface and is responsible for formatting and delivering the notification through its specific transport.

Channel Architecture

public interface NotificationChannel {
    void send(Notification notification, RenderedTemplate template);
    boolean supports(Notification.Channel channel);
}

All channels are auto-discovered by Spring and routed based on the notification's channel field.

Email Channel

The EmailChannel sends emails via SMTP with support for HTML templates, attachments, and tracking pixels.

spring:
  mail:
    host: ${SMTP_HOST}
    port: ${SMTP_PORT}
    username: ${SMTP_USERNAME}
    password: ${SMTP_PASSWORD}
    properties:
      mail.smtp.auth: true
      mail.smtp.starttls.enable: true

Slack Channel

The SlackChannel sends messages to Slack channels via incoming webhooks.

public class SlackChannel implements NotificationChannel {
    // Posts Block Kit formatted messages to Slack webhook URLs
}

Microsoft Teams Channel

The TeamsChannel sends adaptive card messages to Microsoft Teams via webhook connectors.

Push Channel

The PushChannel sends mobile push notifications via Firebase Cloud Messaging (FCM) or Apple Push Notification service (APNs).

In-App Channel

The InAppChannel stores notifications in the database for retrieval by the frontend application. These notifications appear in the user's notification center.

Webhook Channel

The WebhookChannel delivers notifications to arbitrary HTTP endpoints configured by the tenant. It supports custom headers, retry logic, and signature verification.

Channel Selection

When sending a notification, specify the channel in the request:

{
  "channel": "EMAIL"
}

Valid channel values: EMAIL, SMS, PUSH, SLACK, TEAMS, IN_APP, WEBHOOK