Core Architecture Patterns

Layered Architecture Pattern

Three-Tier Structure Implementation

Apply layered architecture with strict separation of concerns:

1. •Presentation Layer: User interface components
2. •Business Logic Layer: Domain rules and operations
3. •Data Access Layer: Database and external service interactions

Enforce unidirectional dependencies:

• •Presentation Layer → Business Logic Layer
• •Business Logic Layer → Data Access Layer
• •Never allow reverse dependencies

Domain Boundaries Enforcement

Separate domain logic from infrastructure:

• •Keep business rules independent of frameworks
• •Use dependency injection for infrastructure concerns
• •Apply Domain-Driven Design principles
• •Define clear bounded contexts for complex domains

Interface segregation requirements:

• •Create specific interfaces for different client needs
• •Avoid fat interfaces with multiple responsibilities
• •Use repository pattern for data access abstraction
• •Implement service interfaces for business operations

Microservices Pattern Guidelines

Service Decomposition Rules

Apply single responsibility principle at service level:

• •Each service owns one business capability
• •Design services around business domains
• •Ensure loose coupling between services
• •Implement high cohesion within services

Communication patterns enforcement:

• •Prefer synchronous communication for critical operations
• •Use asynchronous messaging for event-driven workflows
• •Implement circuit breakers for resilience
• •Apply API gateway pattern for external access

Data Consistency Patterns

Implement eventual consistency where appropriate:

• •Use saga pattern for distributed transactions
• •Apply event sourcing for audit trails
• •Implement CQRS for read/write separation
• •Ensure data ownership boundaries are clear

Event-Driven Architecture Implementation

Event Design Principles

Design immutable, atomic events:

• •Each event represents a single business fact
• •Use past tense for event names (UserRegistered, OrderPlaced)
• •Include all required data in the event payload
• •Apply idempotency handling for duplicate events

Event handling patterns:

• •Implement event handlers as pure functions
• •Use correlation IDs for request tracing
• •Apply dead letter queues for failed events
• •Monitor and log event processing metrics

Message Broker Integration

Configure reliable messaging infrastructure:

• •Set up topic/exchange hierarchies
• •Implement message versioning strategies
• •Configure appropriate quality of service levels
• •Apply backpressure handling for overload protection

Enterprise Integration Patterns

API Design Standards

RESTful API Implementation

Follow REST architectural constraints:

• •Use appropriate HTTP methods (GET, POST, PUT, DELETE)
• •Implement proper status codes for all responses
• •Apply resource-based URL naming conventions
• •Use content negotiation for format handling

API documentation requirements:

• •Generate OpenAPI/Swagger specifications
• •Include comprehensive request/response examples
• •Document error codes and handling procedures
• •Provide authentication and authorization details

GraphQL Integration Patterns

Schema-first development approach:

• •Define clear type system with strong typing
• •Implement proper resolver chains
• •Apply authorization at field level
• •Use data loaders to prevent N+1 queries

Performance optimization techniques:

• •Implement query complexity analysis
• •Apply query depth limiting
• •Use persisted queries for frequently used operations
• •Monitor and log query performance metrics

Security Architecture Patterns

Zero Trust Security Model

Implement defense-in-depth security:

• •Apply least privilege access control
• •Use mTLS for service-to-service communication
• •Implement JWT/OIDC for authentication
• •Apply API throttling and rate limiting

Security monitoring and auditing:

• •Log all security-relevant events
• •Implement intrusion detection systems
• •Apply security information and event management (SIEM)
• •Conduct regular security assessments

Secure API Gateway Configuration

Apply API gateway security patterns:

• •Implement request/response transformation
• •Apply JSON Web Token validation
• •Use web application firewall (WAF) rules
• •Implement distributed tracing for security monitoring

Architecture Quality Attributes

Scalability Patterns

Horizontal Scaling Implementation

Design for stateless services:

• •Externalize session state using distributed caches
• •Use database connection pooling efficiently
• •Implement auto-scaling policies based on metrics
• •Apply blue-green deployment strategies

Performance optimization techniques:

• •Implement caching at multiple levels (CDN, application, database)
• •Use read replicas for database scaling
• •Apply asynchronous processing for non-critical operations
• •Implement sharding strategies for large datasets

Resilience and Fault Tolerance

Implement self-healing mechanisms:

• •Use health checks for service monitoring
• •Apply exponential backoff for retry logic
• •Implement circuit breakers to prevent cascading failures
• •Use chaos engineering for resilience testing

Disaster recovery planning:

• •Implement multi-region deployment strategies
• •Use backup and restore procedures
• •Apply data replication across geographic locations
• •Document and test recovery procedures

Maintainability and Evolution

Technical Debt Management

Apply architectural fitness functions:

• •Define measurable quality metrics
• •Implement automated architecture compliance checks
• •Use architectural decision records (ADRs)
• •Regularly review and refactor architectural decisions

Evolutionary architecture principles:

• •Design for change with loose coupling
• •Use abstraction layers to isolate volatility
• •Implement feature flags for safe deployments
• •Apply strangler fig pattern for legacy system migration

Documentation and Communication

Maintain architectural documentation:

• •Create context diagrams for system overviews
• •Document data flows and integration points
• •Maintain architectural decision records
• •Provide deployment and runbooks

Cross-functional collaboration:

• •Conduct regular architecture reviews
• •Use pair programming for critical components
• •Implement knowledge sharing practices
• •Provide training on architectural standards