Enterprise Forum API | Clean Architecture & AWS Serverless

Building a robust forum management system required handling complex business logic while maintaining clean separation of concerns and enterprise-grade reliability.

The system needed to support:

User authentication with role-based access control (Students/Instructors)

Question and answer management with best answer selection

Real-time comment system for questions and answers

File attachment handling with cloud storage

Notification system for user interactions

API documentation and automated testing

Cost-effective serverless deployment

I designed and implemented a forum API using NestJS with clean architecture principles, deployed on AWS infrastructure with Infrastructure as Code.

The solution follows Domain-Driven Design with clear separation between domain logic, application use cases, and infrastructure concerns.

The serverless architecture leverages AWS Lambda functions running NestJS with API Gateway for HTTP routing. The application is deployed within a private VPC across multiple availability zones for high availability.

Architecture Layers: Domain entities use AggregateRoot pattern with domain events for side effects. Value Objects like Slug and QuestionDetails ensure type safety and encapsulate business rules. The WatchedList pattern manages attachment collections with automatic synchronization.

Advanced Patterns: Domain events trigger notifications automatically when answers are created or best answers are chosen. The Either/Left/Right pattern provides explicit error handling throughout the application, eliminating runtime exceptions.

Infrastructure: The entire AWS infrastructure is provisioned via Terraform, managing VPC configuration, Lambda functions, RDS PostgreSQL database, ElastiCache Redis cluster, and S3 storage. A custom solution handles Prisma migrations within the private VPC using Lambda functions.

Testing Strategy: Unit tests cover all domain entities and use cases with 90%+ coverage. E2E tests validate complete user workflows, including event handling. In-memory repositories enable isolated testing with factory patterns for test data generation.

The forum API delivers a production-ready solution with enterprise-grade architecture:

✓ Scalable serverless architecture handling high traffic with cost optimization ✓ Maintainable codebase following SOLID principles and DDD patterns ✓ Reliable system with 90%+ test coverage and automated quality assurance ✓ Secure infrastructure with VPC isolation and proper access controls ✓ Automated CI/CD pipeline with Infrastructure as Code ✓ Real-time notification system enhancing user engagement ✓ Advanced domain modeling with proper business logic encapsulation