---
title: Architecture Patterns
category: product
entity_type: skill
price: $15
canonical: https://forgehouse.ai/skills/architecture-patterns/
lang: en
hreflang_alt: https://forgehouse.ai/tr/skiller/architecture-patterns/
last_updated: 2026-06-20
---

# Architecture Patterns

> Implement proven backend architecture patterns including Clean Architecture, Hexagonal…

An implementation guide for proven backend architecture patterns: Clean Architecture, Hexagonal (Ports & Adapters), and Domain-Driven Design. It shows how to keep business logic independent of frameworks and databases, with full worked code for entities, use cases, repositories, ports, adapters, value objects, and aggregates, plus enterprise resilience patterns like circuit breakers and graceful degradation.

## Use cases
- Designing a new backend system with clear separation of concerns
- Refactoring a tightly coupled monolith for testability and maintainability
- Implementing the dependency rule so the domain doesn't depend on frameworks
- Modeling a domain with bounded contexts, aggregates, and value objects
- Swapping infrastructure (DB, payment provider) without touching the core
- Adding circuit breakers and graceful degradation to external integrations

## Benefits
- A core you can unit-test without a database, UI, or external services
- Freedom to swap technologies by writing a new adapter, not rewriting logic
- Lower cognitive load and cleaner boundaries via bounded contexts
- A resilient system that keeps running when an external service goes down

## What’s included
- Clean Architecture directory structure with full entity/use-case/adapter code
- Hexagonal ports-and-adapters with mockable test implementations
- DDD tactical patterns: entities, value objects, aggregate roots, domain events
- An anti-corruption layer pattern for taming external system models
- A lightweight CQRS variant separating write and read models
- Enterprise resilience patterns: circuit breaker, bulkhead, retry with backoff, health checks

## Who it’s for
Backend engineers and architects building or refactoring complex systems that need to stay testable and maintainable at scale.

## How it runs
Clean Architecture is earned, not defaulted. The first check is whether the domain justifies the layers at all; only then do ports, adapters and DDD tactics go in:
1. Starts with the over-engineering check: simple CRUD does not get clean architecture; every added layer must answer what would be lost without it.
2. Lays the layers so dependencies only point inward: entities and abstract interfaces live in the domain, use cases orchestrate business rules, adapters implement, frameworks and drivers stay at the outermost ring.
3. The domain defines ports (IUserRepository, PaymentGatewayPort, NotificationPort) and infrastructure provides the adapters (Postgres, Stripe, Mock), so the core is testable with zero database or external service.
4. Runs the DDD tactical pass: value objects immutable and self-validating, aggregates as consistency boundaries with the root as the only entry point, repositories defined only on aggregate roots, cross-context communication via domain events.
5. External systems pass through an anti-corruption layer: a Stripe charge.succeeded webhook becomes a domain PaymentCompleted event; foreign data shapes, retries and timeouts never leak into the core.
6. Wraps every external call in resilience patterns: circuit breaker opening after five consecutive failures with a 30-second half-open probe, graceful degradation so the site keeps working, exponential backoff retry that never retries on 4xx.

## FAQ
### Does this assume a particular language or framework?
The patterns are language-agnostic by design, since the whole point is keeping the domain independent of any framework, and they come with full worked code for entities, use cases, repositories, ports, and adapters. The patterns don't dictate a stack; you adapt the examples to yours.

### Won't Clean and Hexagonal just add layers of indirection I don't need?
For a complex system that indirection is what makes the domain testable without a database or framework attached. The cost is real, which is why the guidance aims at systems that need to stay maintainable, not throwaway scripts.

### I'm building a basic CRUD app, is this the right fit?
Probably not; these patterns earn their keep when business logic is complex and long-lived, and on simple CRUD they're overhead. Reach for them when coupling is actively hurting testability, not preemptively.

## Price
$15, one-time, no subscription. VAT included.

Related guide: [AI code review and developer workflow](https://forgehouse.ai/guides/ai-code-review/)