BE-014 — Implement Notification & Event Delivery Service

[dDevAhmed]

BE-014 — Implement Notification & Event Delivery Service

📚 Overview

The Notification & Event Delivery Service is responsible for delivering real-time and asynchronous notifications across the TruthBounty ecosystem.

As protocol activity grows, users need immediate awareness of events such as claim submissions, verification requests, disputes, governance proposals, voting deadlines, reputation updates, staking changes, reward distributions, and security alerts.

Rather than allowing every backend module to send notifications independently, this service centralises event processing, notification routing, delivery preferences, and retry mechanisms into a single production-ready infrastructure.

The Notification Service will become the dependency for:

• Frontend Web Application
• Mobile Application
• Governance Dashboard
• Moderator Console
• Administration Portal
• Analytics Platform
• AI Assistant
• External Integrations

Every downstream module assumes notifications are reliable, idempotent, and delivered according to user preferences.

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🧠 Background

TruthBounty V2 contains numerous independent protocol modules capable of producing events.

Examples include:

• new claims
• verification assignments
• dispute creation
• dispute resolution
• reputation updates
• staking changes
• governance proposals
• proposal voting
• reward distributions
• moderation actions
• security alerts

Without a dedicated notification service:

• duplicate notifications may occur
• delivery failures become difficult to recover
• notification preferences become inconsistent
• frontend applications require unnecessary polling

A centralised Notification Service ensures scalable and reliable event delivery while remaining independent of protocol business logic.

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🎯 Objectives

Implement a production-ready Notification Service that:

• consumes protocol events
• delivers notifications
• supports multiple notification channels
• manages user notification preferences
• retries failed deliveries
• records delivery history
• exposes notification APIs
• supports future communication channels

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🧩 Technical Scope

1. Notification API

Implement endpoints supporting:

• list notifications
• unread notifications
• mark as read
• mark all as read
• notification history
• notification deletion

Support pagination and filtering.

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2. Event Consumption

Consume events generated by:

• blockchain indexer
• governance service
• reputation service
• verification service
• dispute service
• reward service
• administration service

The Notification Service must not generate protocol events itself.

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3. Notification Channels

Support delivery through:

• in-app notifications
• WebSocket events
• push notifications
• email
• webhook integrations

Additional channels should be extensible.

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4. User Preferences

Allow contributors to configure:

• enabled notification channels
• notification categories
• email preferences
• governance alerts
• staking alerts
• reward notifications
• security alerts

Preference changes must take effect immediately.

---

5. Delivery Queue

Implement an asynchronous delivery queue supporting:

• retries
• exponential backoff
• dead-letter queues
• delivery prioritisation
• scheduled notifications

Queue processing should be resilient to transient failures.

---

6. Delivery History

Record:

• notification identifier
• recipient
• delivery channel
• delivery timestamp
• delivery status
• retry attempts
• failure reasons

Delivery history should support operational auditing.

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7. Real-Time Delivery

Support:

• WebSocket broadcasting
• Server-Sent Events (SSE)
• event subscriptions
• connection recovery
• reconnect handling

Real-time updates should minimise frontend polling.

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8. Security

Ensure:

• authenticated recipients
• secure event routing
• notification ownership validation
• rate limiting
• webhook signature verification

Sensitive notifications must never be delivered to unauthorised users.

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9. Monitoring

Expose metrics including:

• notifications sent
• delivery success rate
• failed deliveries
• retry counts
• queue depth
• processing latency

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10. Future Extensibility

Design the service to support:

• SMS notifications
• Telegram
• Discord
• Slack
• Microsoft Teams
• enterprise messaging platforms

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✅ Acceptance Criteria

• Notifications can be created successfully.
• User preferences are respected.
• WebSocket notifications function correctly.
• Email delivery operates reliably.
• Retry logic functions correctly.
• Delivery history is recorded.
• Monitoring metrics are available.
• Unit and integration tests pass.

---

🧪 Testing Requirements

Implement tests covering:

• notification creation
• preference management
• WebSocket delivery
• email delivery
• retry behaviour
• queue processing
• webhook delivery
• authentication
• concurrent notification processing
• performance benchmarking

---

📚 Documentation

Update:

• Backend API Documentation
• Notification Service Architecture
• Event Processing Documentation
• OpenAPI Specification
• Operational Runbook

---

🔗 Dependencies

Depends on:

• BE-003 — Implement Blockchain Indexing Service
• BE-004 — Implement Redis Cache & Distributed Session Layer
• BE-010 — Implement Reputation API
• BE-011 — Implement Governance API
• BE-012 — Implement Analytics API

Blocks:

• Frontend Notification Centre
• Mobile Push Notifications
• Governance Dashboard
• Moderator Console
• Administration Portal
• AI Assistant

---

🏷 Labels

• backend
• realtime
• architecture
• protocol-critical
• complexity-medium
• stellar-wave

---

📊 Complexity

Medium

The Notification Service coordinates asynchronous event processing, real-time communication, delivery queues, and user preferences. While it does not influence protocol state, it is essential for delivering a responsive and reliable user experience across all TruthBounty applications.

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⏱ Estimated Effort

5–6 days

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🚀 Definition of Done

• Notification API implemented.
• Event consumers operational.
• WebSocket delivery functioning.
• Email delivery integrated.
• User preferences supported.
• Retry queue operational.
• Monitoring enabled.
• Tests passing.
• Documentation updated.
• Ready for integration with the Frontend, Mobile Application, Governance Dashboard, Moderator Console, Administration Portal, and AI Assistant.

[RemmyAcee]

@RemmyAcee has applied to work on this issue as part of the Stellar Wave Program's 7th wave.

I'd like to be assigned to this issue. I'll deliver a clean, maintainable solution that matches the requirements.

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[VeronicDev]

@VeronicDev has applied to work on this issue as part of the Stellar Wave Program's 7th wave.

Hello maintainer pls assign

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[nafiuishaaq]

@nafiuishaaq has applied to work on this issue as part of the Stellar Wave Program's 7th wave.

I'd like to be assigned to this issue. I'll deliver a clean, maintainable solution

ℹ️ Repo Maintainers: To accept this application, review their application or assign @nafiuishaaq to this issue.

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[drips-wave]

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