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Notification Service API

✉️

A comprehensive notification management REST API built with Java, Spring Boot, and PostgreSQL. Delivers notifications via email, SMS, push notifications, and in-app messages with templating and scheduling support.

Features

Feature Description Icon
Multi-Channel Delivery Send via email, SMS, push notifications, and in-app messages 📨
Template Management Create and manage notification templates with variables 📝
Scheduling Schedule notifications for future delivery ⏰
Delivery Tracking Track delivery status and user interactions 📊
Unsubscribe Management Respect user preferences and unsubscribe requests 🚫
Rate Limiting Prevent notification spam with configurable limits ⚡
Multi-Tenant Support Isolate notifications per tenant 🏢

Architecture Overview

flowchart TD
    A[Client] -->|REST API| B(NotificationController)
    B --> C[NotificationService]
    C --> D[TemplateService]
    C --> E[ChannelService]
    D --> F[TemplateRepository]
    E --> G[EmailProvider]
    E --> H[SMSProvider]
    E --> I[PushProvider]
    F --> J[(PostgreSQL)]
    C --> K[Message Queue]
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API Endpoints

Note: Real API endpoints to be provided and included here.

Method Endpoint Description Notes/Parameters
POST /api/v1/notifications/send Send notification immediately tenantId header, notification data
POST /api/v1/notifications/schedule Schedule notification for later Scheduled time, notification data
GET /api/v1/notifications/{id} Get notification details
POST /api/v1/templates Create notification template Template name, body, variables

Sequence: Send Scheduled Notification

sequenceDiagram
    participant U as User
    participant API as NotificationController
    participant N as NotificationService
    participant T as TemplateService
    participant Q as Message Queue
    participant C as ChannelService
    U->>API: POST /notifications/schedule (template, time)
    API->>N: validate notification
    N->>T: load template
    T-->>N: template loaded
    N->>Q: queue scheduled notification
    Q-->>N: queued
    N-->>API: NotificationResponse
    API-->>U: 201 Created + notification details
    Note over Q,C: At scheduled time...
    Q->>N: trigger notification
    N->>C: send via channels
    C->>C: email + SMS
    C-->>N: delivery confirmed
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Database Schema

erDiagram
    notifications {
        UUID id PK
        UUID tenant_id
        VARCHAR notification_type
        VARCHAR recipient
        VARCHAR channel
        VARCHAR status
        TIMESTAMP scheduled_at
        TIMESTAMP sent_at
        TIMESTAMP created
        TIMESTAMP updated
    }

    notification_templates {
        UUID id PK
        UUID tenant_id
        VARCHAR template_name
        VARCHAR template_type
        TEXT template_body
        TEXT subject
        JSON variables
        TIMESTAMP created
        TIMESTAMP updated
    }

    user_preferences {
        UUID id PK
        UUID user_id
        UUID tenant_id
        BOOLEAN email_enabled
        BOOLEAN sms_enabled
        BOOLEAN push_enabled
        BOOLEAN in_app_enabled
        TIMESTAMP updated
    }

    delivery_logs {
        UUID id PK
        UUID notification_id FK
        VARCHAR delivery_channel
        VARCHAR delivery_status
        TEXT error_message
        TIMESTAMP delivered_at
        TIMESTAMP created
    }

    notifications ||--o{ delivery_logs : "tracked_by"
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Getting Started

Prerequisites

  • Java 17+
  • PostgreSQL
  • Gradle
  • Message Queue (RabbitMQ/Kafka)

Setup

git clone https://github.com/Olanna-tech/notification-service-java.git
cd notification-service-java
./gradlew build

Database

  • Configure your PostgreSQL credentials in src/main/resources/application.yml.
  • Run Flyway migrations (auto on startup).

Run

./gradlew bootRun

Configuration

Set the following environment variables in application.yml: 

notification:
  email-provider: sendgrid
  sendgrid-api-key: your-api-key
  sms-provider: twilio
  push-provider: firebase
  rate-limit-per-user-per-day: 100
  queue-type: rabbitmq

Contributing

Pull requests are welcome! For major changes, please open an issue first.

License

MIT

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