🛡️ Hexagonal Architecture (Ports and Adapters)¶

Info

At ConnectSoft, Hexagonal Architecture (also known as the Ports and Adapters pattern) is a core design foundation used to ensure that systems are technology-agnostic, testable, and adaptable to change.
It reinforces the principles of domain purity, dependency inversion, and separation of concerns — enabling resilient, modular, cloud-native, and event-driven platforms.

🎯 Introduction¶

Hexagonal Architecture structures a system around a core domain logic, completely decoupled from external technologies such as databases, web frameworks, messaging systems, or UIs.

The core defines the business rules and application logic.
Ports represent abstract points of interaction — they define how the system communicates with the outside world.
Adapters implement these ports to connect the system to external systems, protocols, or devices.

This ensures that technologies can change without impacting the domain, and testing can be performed purely at the domain level without reliance on infrastructure.

🧠 Core Concepts¶

Concept	Description
Domain Core	Business logic, use cases, and entities that express the real problem space.
Ports	Interfaces that define allowed interactions — inbound and outbound.
Adapters	Concrete implementations of ports to handle real-world technologies.

🏛️ Structure Overview¶

flowchart TD
    ExternalSystem1((User Interface))
    ExternalSystem2((External API))
    ExternalSystem3((Database))
    ExternalSystem4((Message Broker))

    ExternalSystem1 -->|Primary Adapter| PrimaryPort
    ExternalSystem2 -->|Primary Adapter| PrimaryPort

    SecondaryPort -->|Secondary Adapter| ExternalSystem3
    SecondaryPort -->|Secondary Adapter| ExternalSystem4

    PrimaryPort --> CoreDomain
    CoreDomain --> SecondaryPort

Hold "Alt" / "Option" to enable pan & zoom

✅ Primary Adapters: Handle inbound communication (e.g., HTTP Controllers, CLI Interfaces).
✅ Secondary Adapters: Handle outbound communication (e.g., Persistence, Event Publishing).

🌟 Principles¶

Dependency Inversion:
The core defines the contracts (ports); infrastructure depends on the core, not vice versa.
Isolation of Technology:
Frameworks, databases, and external services are kept at the boundary, easily swappable.
Testability by Design:
Core domain can be tested independently using mock adapters.
Adaptability and Resilience:
Changing a database, messaging broker, or API endpoint requires changes only in adapters.

🔗 How It Connects to ConnectSoft’s Platform¶

Hexagonal Architecture underpins many ConnectSoft components:

Microservices — with clean separation between business logic and API/DB layers.
API Gateways — where request routing logic is completely decoupled from infrastructure.
Event-Driven Services — emitting domain events through secondary ports without knowing delivery technology.
AI Agents — interfacing domain logic with AI orchestration layers via adapter strategies.

📌 Hexagonal Architecture is the bridge between ConnectSoft’s domain-driven designs and its scalable, resilient, and cloud-native execution models.

📋 Summary of Core Concepts¶

Area	ConnectSoft Approach
Domain Core	Owns use cases, entities, domain rules
Primary Ports	Define incoming actions (e.g., commands, queries)
Secondary Ports	Define outgoing actions (e.g., repository, events, APIs)
Primary Adapters	Implement inbound ports (e.g., REST controllers, gRPC)
Secondary Adapters	Implement outbound ports (e.g., repositories, brokers)
Isolation Strategy	Domain core is free from any external technology influence

🧱 Components of Hexagonal Architecture¶

In Hexagonal Architecture, systems are organized around roles, not technologies.
At ConnectSoft, each component of the hexagon is designed with strict responsibility boundaries to maximize resilience, testability, and maintainability.

🧠 Domain Core (Inside the Hexagon)¶

The Domain Core encapsulates:

Entities
Represent domain objects with identity and lifecycle.
Value Objects
Model descriptive aspects without identity.
Aggregates
Group domain entities for consistency boundaries.
Domain Services
Contain stateless operations that don't belong to a single entity.
Use Cases (Application Services)
Orchestrate business workflows by invoking domain logic.

The core is completely pure — no frameworks, no infrastructure code, no external dependencies.

public interface IPlaceOrderUseCase
{
    Task PlaceOrderAsync(Guid customerId, List<Guid> productIds);
}

✅ Ports (interfaces) are defined inside the core.

🔗 Ports¶

Ports are abstract interfaces that define how the application communicates with the outside world.

Port Type	Purpose	Example
Primary Ports	Allow external systems to invoke core functionality	`IPlaceOrderUseCase` (e.g., API calls)
Secondary Ports	Allow core to communicate outward to external services	`IOrderRepository` (e.g., database access)

Primary Ports¶

Interfaces exposed by the Core, to be called by external actors.

public interface IRegisterUserUseCase
{
    Task RegisterAsync(string email, string password);
}

Adapters like API Controllers or CLI commands implement the wiring to call these ports.

Secondary Ports¶

Interfaces that the Core uses to perform external operations.

public interface ICustomerRepository
{
    Task<Customer> GetByIdAsync(Guid id);
    Task SaveAsync(Customer customer);
}

Adapters like database repositories, message publishers, or HTTP clients implement these interfaces.

🎯 Primary Adapters (Inbound)¶

Primary Adapters implement external inputs, adapting them into port invocations.

Adapter Type	Example
REST API Controller	Exposes HTTP endpoints that call use cases
gRPC Service	Handles remote calls to the system
CLI Command	Accepts console input
Messaging Consumer	Receives event messages

Example: REST API Controller Adapter

[ApiController]
[Route("api/orders")]
public class OrderController : ControllerBase
{
    private readonly IPlaceOrderUseCase _placeOrder;

    public OrderController(IPlaceOrderUseCase placeOrder)
    {
        _placeOrder = placeOrder;
    }

    [HttpPost]
    public async Task<IActionResult> PlaceOrder([FromBody] PlaceOrderRequest request)
    {
        await _placeOrder.PlaceOrderAsync(request.CustomerId, request.ProductIds);
        return Ok();
    }
}

✅ The controller doesn't contain business logic — it delegates to the Core.

🎯 Secondary Adapters (Outbound)¶

Secondary Adapters implement external outputs, fulfilling secondary ports.

Adapter Type	Example
Database Repository	Persists aggregates to a database
Message Publisher	Publishes events to a broker
External API Client	Calls third-party services
File Storage Client	Saves files to blob storage

Example: Repository Adapter

public class CustomerRepository : ICustomerRepository
{
    private readonly ApplicationDbContext _dbContext;

    public CustomerRepository(ApplicationDbContext dbContext)
    {
        _dbContext = dbContext;
    }

    public async Task<Customer> GetByIdAsync(Guid id)
    {
        return await _dbContext.Customers.FindAsync(id);
    }

    public async Task SaveAsync(Customer customer)
    {
        _dbContext.Customers.Update(customer);
        await _dbContext.SaveChangesAsync();
    }
}

✅ Infrastructure details (e.g., EF Core) are hidden from the domain.

🧩 Full Component Diagram¶

flowchart TB
    PrimaryAdapter1((REST Controller))
    PrimaryAdapter2((CLI Command))
    PrimaryAdapter3((gRPC Service))

    SecondaryAdapter1((Database Repository))
    SecondaryAdapter2((Message Broker Publisher))

    PrimaryAdapter1 -->|Invokes| PrimaryPort
    PrimaryAdapter2 -->|Invokes| PrimaryPort
    PrimaryAdapter3 -->|Invokes| PrimaryPort

    PrimaryPort --> CoreDomain
    CoreDomain --> SecondaryPort
    SecondaryPort --> SecondaryAdapter1
    SecondaryPort --> SecondaryAdapter2

Hold "Alt" / "Option" to enable pan & zoom

✅ Ports define the interaction contracts.
✅ Adapters connect real-world concerns to the pure core logic.

📋 Component Responsibilities Summary¶

Component	Responsibility
Domain Core	Business rules and use cases, technology-agnostic
Primary Ports	Expose system capabilities (application services)
Secondary Ports	Request external capabilities (e.g., persistence)
Primary Adapters	Translate external requests into core use case invocations
Secondary Adapters	Implement core output contracts for infrastructure interaction

🧱 Layered Structure and Flow in Hexagonal Architecture¶

At ConnectSoft, every Hexagonal service is built around strict, traceable dependency rules and layered communication flow to maintain system integrity, adaptability, and clean testability.

🧩 Logical Layering¶

Layer	Description	ConnectSoft Focus
Domain Core	Pure business logic and use cases, no dependencies outward	✅
Ports	Contracts to communicate in and out of the core	✅
Adapters	Technology-specific implementations of ports	✅
Infrastructure	External systems like databases, APIs, queues	✅

🔀 Dependency Rules¶

✅ Adapters and infrastructure depend on Core, never the other way around.

✅ Ports are owned by the Core and implemented by Adapters.

✅ Infrastructure can change without modifying the Domain Core.

flowchart TB
    UIClient --> PrimaryAdapter
    PrimaryAdapter --> PrimaryPort
    PrimaryPort --> DomainCore
    DomainCore --> SecondaryPort
    SecondaryPort --> SecondaryAdapter
    SecondaryAdapter --> ExternalService

Hold "Alt" / "Option" to enable pan & zoom

✅ One-way arrows always point toward the Core.

🔥 Flow of Execution¶

External request hits a Primary Adapter (e.g., API call).
Primary Adapter calls a Primary Port (use case interface).
Core Domain processes business rules.
Core calls Secondary Ports (repository, publisher, client).
Secondary Adapters interact with Infrastructure (DB, message broker).

🧠 C# Code Example: Full Flow¶

1. Primary Port (Use Case Interface)¶

public interface ICreateOrderUseCase
{
    Task<Guid> CreateOrderAsync(Guid customerId, List<Guid> productIds);
}

2. Domain Core Implementation (Use Case)¶

public class CreateOrderService : ICreateOrderUseCase
{
    private readonly IOrderRepository _orderRepository;

    public CreateOrderService(IOrderRepository orderRepository)
    {
        _orderRepository = orderRepository;
    }

    public async Task<Guid> CreateOrderAsync(Guid customerId, List<Guid> productIds)
    {
        var order = Order.Create(customerId, productIds);
        await _orderRepository.SaveAsync(order);
        return order.Id;
    }
}

✅ The domain core only depends on Ports (interfaces).

3. Secondary Port (Repository Interface)¶

public interface IOrderRepository
{
    Task SaveAsync(Order order);
}

4. Secondary Adapter (Infrastructure)¶

public class OrderRepository : IOrderRepository
{
    private readonly AppDbContext _dbContext;

    public OrderRepository(AppDbContext dbContext)
    {
        _dbContext = dbContext;
    }

    public async Task SaveAsync(Order order)
    {
        _dbContext.Orders.Add(order);
        await _dbContext.SaveChangesAsync();
    }
}

✅ The repository depends on EF Core but the core does not.

5. Primary Adapter (REST Controller)¶

[ApiController]
[Route("api/orders")]
public class OrdersController : ControllerBase
{
    private readonly ICreateOrderUseCase _createOrder;

    public OrdersController(ICreateOrderUseCase createOrder)
    {
        _createOrder = createOrder;
    }

    [HttpPost]
    public async Task<IActionResult> CreateOrder([FromBody] CreateOrderRequest request)
    {
        var orderId = await _createOrder.CreateOrderAsync(request.CustomerId, request.ProductIds);
        return Ok(new { OrderId = orderId });
    }
}

✅ Controller knows nothing about the database, message queues, or infrastructure.

📚 Layered Mapping Summary¶

Layer	Example in ConnectSoft
Domain Core	`Order`, `OrderService`
Primary Port	`ICreateOrderUseCase`
Secondary Port	`IOrderRepository`
Primary Adapter	`OrdersController`
Secondary Adapter	`OrderRepository`

🌟 Best Practices for Layering at ConnectSoft¶

✅ Protect the Core at all costs — never let infrastructure leak in.
✅ Define clear Ports for inbound and outbound operations.
✅ Favor Dependency Injection for all Adapter bindings.
✅ Keep Adapters dumb — they only translate requests/responses.

Tip

If an infrastructure change (like switching from SQL to NoSQL) requires changes inside your domain layer,
it signals a violation of Hexagonal principles.

🌟 Benefits and Trade-Offs of Hexagonal Architecture¶

At ConnectSoft, adopting Hexagonal Architecture is not just a preference — it is a strategic choice that aligns every system with domain purity, adaptability, and enterprise resilience.

However, like any powerful architecture, it introduces both significant benefits and some complexities that must be managed wisely.

✅ Key Benefits¶

Benefit	Description
Technology Agnosticism	Core logic is isolated from frameworks, databases, and protocols.
Testability by Default	Core can be tested independently of infrastructure, with mock ports.
Flexibility and Adaptability	Swapping infrastructure (e.g., database, broker) does not impact core business rules.
Clear Responsibility Separation	Adapters focus on translation; Core focuses on business.
Portability	Core logic can be reused across different delivery mechanisms (e.g., API, CLI, Message Bus).
Resilience to Change	Evolving external technologies is simplified — only adapters change.

📈 Diagram: Benefits Mapping¶

flowchart LR
    HexagonalArchitecture --> TechnologyAgnostic
    HexagonalArchitecture --> Testable
    HexagonalArchitecture --> Flexible
    HexagonalArchitecture --> ClearSeparation
    HexagonalArchitecture --> Portable
    HexagonalArchitecture --> Resilient

Hold "Alt" / "Option" to enable pan & zoom

✅ Each benefit strengthens ConnectSoft’s platform evolution strategy.

⚠️ Trade-Offs and Challenges¶

Challenge	Description
Initial Complexity	Setting up layers (ports, adapters, dependency injection) requires careful upfront work.
Overengineering Risk	For small projects, Hexagonal layering can feel heavy or unnecessary.
Developer Onboarding Time	New developers need to learn the internal architecture to navigate effectively.
Multiple Layers of Indirection	Following requests through ports and adapters adds cognitive load.

🔥 Example of Complexity¶

Without discipline, developers might:

Duplicate adapter logic across services.
Leak database entities into the Domain Core.
Violate dependency inversion unintentionally.

Warning

In ConnectSoft platforms, strict architectural linting is enforced to prevent these mistakes.
No direct infrastructure access is permitted from domain layers.

🧠 Best Practices to Maximize Benefits at ConnectSoft¶

✅ Template First
Use ConnectSoft base templates that scaffold ports, adapters, dependency wiring, and testing stubs.

✅ Strict Core Protection
Ensure that all dependencies point inward toward the domain. No accidental outward calls.

✅ Explicit Ports Always
Do not rely on generic services or dynamic bindings. Ports should be clear, versioned, and traceable.

✅ Test Core in Isolation
Build unit tests directly against use cases without real database, queues, or HTTP servers.

✅ Evolve Adapters, Not Core
Adapters can be reworked freely (e.g., from REST to GraphQL) without touching the domain.

✅ Invest in Onboarding
Document and visualize the Hexagonal structure for every new team member.

📋 Benefit vs Trade-Off Summary Table¶

Category	Benefit	Trade-Off
Agility	Infrastructure independence	Requires rigorous layering
Quality	Easy unit testing	Initial learning curve
Flexibility	Easy to adapt to technology shifts	More moving parts to manage
Clarity	Clear separation of concerns	Slight overhead for small apps

Tip

At ConnectSoft, we apply Hexagonal Architecture even for internal tools and microservices —
because small systems today can become mission-critical tomorrow.

🧩 ConnectSoft Hexagonal Architecture Blueprint¶

At ConnectSoft, Hexagonal Architecture is not just a theoretical model —
it is the operational blueprint for how we build SaaS platforms, microservices ecosystems, API gateways, and AI orchestration engines.

Every system we design aligns with the Hexagonal pattern to ensure:

✅ Business-first domain modeling
✅ Technology-agnostic resilience
✅ Infrastructure adaptability
✅ Cloud-native and event-driven enablement

🏛️ Platform-Wide Application of Hexagonal Principles¶

Platform Area	Hexagonal Application Pattern
Microservices	Each service encapsulates domain logic, ports, and adapters.
API Gateway	Gateway routes requests to primary ports of downstream services.
Event-Driven Architecture	Consumers and producers adapt to ports for event handling.
AI Engines (Semantic Kernel)	Core AI logic exposed through ports, adapters integrate storage, APIs.
SaaS Tenant Management	Tenant lifecycle logic isolated via ports; adapters manage DB, auth, billing.

📚 ConnectSoft Example: SaaS Service Hexagon¶

flowchart TD
    WebClient -->|HTTP POST| CreateTenantAdapter
    CLI -->|CLI Command| CreateTenantAdapter
    EventConsumer -->|Event| CreateTenantAdapter

    CreateTenantAdapter --> CreateTenantPort
    CreateTenantPort --> TenantServiceDomainCore

    TenantService --> TenantRepositoryPort
    TenantService --> BillingServicePort
    TenantRepositoryPort --> TenantRepositoryAdapter
    BillingServicePort --> BillingApiAdapter

Hold "Alt" / "Option" to enable pan & zoom

✅ External actors (Web, CLI, Event Consumer) interact via Primary Adapters.
✅ Domain Core enforces business rules through Ports.
✅ Secondary Adapters implement infrastructure-specific operations.

🛠️ Sample Hexagonal Use Case: Tenant Registration¶

Primary Port¶

public interface IRegisterTenantUseCase
{
    Task<Guid> RegisterAsync(string companyName, string adminEmail);
}

Domain Service (Use Case Implementation)¶

public class RegisterTenantService : IRegisterTenantUseCase
{
    private readonly ITenantRepository _tenantRepository;
    private readonly IBillingService _billingService;

    public RegisterTenantService(ITenantRepository tenantRepository, IBillingService billingService)
    {
        _tenantRepository = tenantRepository;
        _billingService = billingService;
    }

    public async Task<Guid> RegisterAsync(string companyName, string adminEmail)
    {
        var tenant = Tenant.Create(companyName, adminEmail);
        await _tenantRepository.SaveAsync(tenant);
        await _billingService.CreateAccountAsync(tenant.Id);
        return tenant.Id;
    }
}

Secondary Ports¶

public interface ITenantRepository
{
    Task SaveAsync(Tenant tenant);
}

public interface IBillingService
{
    Task CreateAccountAsync(Guid tenantId);
}

Secondary Adapters¶

public class TenantRepository : ITenantRepository
{
    // Save to database
}

public class BillingApiClient : IBillingService
{
    // Call external billing API
}

✅ Core logic never touches database or APIs directly.

🌍 Blueprint: Across ConnectSoft Ecosystem¶

Service Type	Ports Exposed	Adapters Implemented
Order Service	`IPlaceOrderUseCase`, `IOrderRepository`	REST Controller, SQL Repo, Kafka Producer
User Management	`IRegisterUserUseCase`, `IUserRepository`	REST API Adapter, Azure AD B2C Adapter
Billing Service	`IChargeTenantUseCase`, `IPaymentGatewayPort`	gRPC Adapter, Stripe API Adapter
AI Orchestration Agent	`IAnalyzeInputUseCase`, `IKnowledgeBasePort`	HTTP Adapter, Blob Storage Adapter
API Gateway	Routes to service primary ports only	Path-to-port routing Adapter

🔗 Hexagonal Across Event-Driven Workflows¶

Events emitted from the Core through Secondary Ports.
Event Consumers wired as Primary Adapters that trigger use cases.
Ports define contracts for publishing and consuming domain events.

sequenceDiagram
    API->>PrimaryAdapter: HTTP Request
    PrimaryAdapter->>UseCase: Execute Command
    UseCase->>DomainEntity: Apply Changes
    UseCase->>SecondaryPort: Publish Event
    SecondaryAdapter->>MessageBroker: Publish Domain Event

Hold "Alt" / "Option" to enable pan & zoom

✅ All event handling is port-driven, not infrastructure-driven.

📋 ConnectSoft Hexagonal Blueprint Principles¶

Principle	ConnectSoft Practice
Isolate Domain Logic	Never depend on frameworks, databases, or brokers inside core
Explicit Ports	Clear, well-defined interfaces for all interactions
Adaptable Adapters	Infrastructure swaps do not impact core functionality
Event and Command Driven	Ports serve both request/response and event-based workflows
Template-First Execution	All new services scaffolded with hexagonal templates

Tip

Hexagonal Architecture at ConnectSoft is not an optional style —
it is the platform enforcement mechanism that guarantees agility, resilience, and scale for every product we deliver.

📦 Real-World Use Cases of Hexagonal Architecture at ConnectSoft¶

Hexagonal Architecture enables ConnectSoft systems to be resilient, modular, and cloud-native, across a wide variety of real-world domains and technical demands.

Below are selected examples showcasing practical applications of ports and adapters in different environments.

🛍️ E-Commerce Microservice: Order Management¶

📖 Scenario¶

Customers place orders via a web app.
Orders must be persisted, inventory adjusted, and events published for further processing.

🧠 Structure¶

Layer	Implementation
Primary Adapters	REST API Controller (HTTP)
Core Ports	`IPlaceOrderUseCase`, `IOrderRepository`, `IEventPublisher`
Secondary Adapters	SQL Database Adapter (EF Core), Kafka Publisher Adapter

🛠️ Flow Diagram¶

flowchart TD
    WebClient -->|HTTP POST| OrderApiController
    OrderApiController --> PlaceOrderUseCase
    PlaceOrderUseCase --> OrderRepository
    PlaceOrderUseCase --> EventPublisher
    OrderRepository --> Database
    EventPublisher --> Kafka

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✅ All infrastructure is accessed through Ports only.

🧩 Key Best Practices¶

Core domain owns Order aggregate lifecycle.
Order placement emits OrderPlacedEvent to Kafka via IEventPublisher.
Event publishing and database saving are fully decoupled.

🤖 AI Workflow Orchestration Service¶

📖 Scenario¶

AI agents execute workflows and store intermediate results.
Responses must be written to both blob storage and exposed via API.

🧠 Structure¶

Layer	Implementation
Primary Adapters	Semantic Kernel Adapter, REST Controller
Core Ports	`IExecuteWorkflowUseCase`, `IStoragePort`
Secondary Adapters	Azure Blob Storage Adapter, Database Adapter

🛠️ Flow Diagram¶

flowchart TD
    SemanticKernelAgent --> SemanticAdapter
    SemanticAdapter --> ExecuteWorkflowUseCase
    ExecuteWorkflowUseCase --> StoragePort
    StoragePort --> AzureBlobStorageAdapter
    StoragePort --> DatabaseAdapter

Hold "Alt" / "Option" to enable pan & zoom

✅ AI engine code only interacts with the core, not with Azure SDKs or APIs directly.

🧩 Key Best Practices¶

Workflow execution logic remains storage-agnostic.
Adapters switchable between Azure, AWS, or even local storage without touching core.

📡 Event-Driven Inventory Service¶

📖 Scenario¶

Inventory Service reacts to OrderPlacedEvent to reserve stock.
Service must handle failures gracefully without affecting ordering flow.

🧠 Structure¶

Layer	Implementation
Primary Adapters	Kafka Consumer Adapter
Core Ports	`IReserveStockUseCase`, `IInventoryRepository`
Secondary Adapters	SQL Repository, Event Publisher Adapter

🛠️ Flow Diagram¶

flowchart TD
    KafkaBroker --> KafkaConsumer
    KafkaConsumer --> ReserveStockUseCase
    ReserveStockUseCase --> InventoryRepository
    InventoryRepository --> SQLDatabase

Hold "Alt" / "Option" to enable pan & zoom

✅ Event consumption acts through a primary adapter into a pure core.

🧩 Key Best Practices¶

Inventory adjustments based only on domain events.
Service idempotency and retry strategies managed at adapter layer.
Side-effects (e.g., publishing confirmation events) are separated via secondary ports.

📚 Recap: Best Practices for Hexagonal Use Cases¶

Practice	Description
Always Separate Adapters	Keep all technologies outside the domain core.
Model Ports Explicitly	Interfaces for both inbound (commands) and outbound (actions).
Isolate Event Handling	Events enter via Primary Adapters, not tangled into core logic.
Favor Port-Based Testing	Core is tested by mocking ports, not infrastructure.
Infrastructure Changes are Adapter Changes	Core remains stable across technology shifts.

Tip

At ConnectSoft, every real-world service — from microservices to AI agents —
is built ports-first, domain-centered, and adapter-isolated to guarantee longevity, maintainability, and speed of innovation.

🧠 Hexagonal Architecture vs Other Architectural Styles¶

At ConnectSoft, we recognize that Hexagonal Architecture did not emerge in isolation —
it evolved alongside other architectures that aim to improve modularity, testability, and adaptability.
Understanding how Hexagonal compares ensures clarity and consistent application across all platforms.

📚 High-Level Comparison Table¶

Architecture	Focus	How Hexagonal Relates or Improves
Layered Architecture	Strict vertical layers (UI → Business → Data)	Hexagonal removes layer-to-layer rigidity via Ports/Adapters.
Onion Architecture	Domain Core in center, dependencies inward	Hexagonal formalizes inbound/outbound communication via Ports.
Clean Architecture	Policy-driven design, frameworks at outer circle	Hexagonal is Clean in spirit, but interaction-focused.
Domain-Driven Design (DDD)	Modeling domain with Entities, Aggregates, etc.	Hexagonal hosts DDD tactical patterns inside cleanly.
Microservices Architecture	Independently deployable services with bounded contexts	Hexagonal is inside each microservice to enforce internal consistency.

🏛️ Layered Architecture vs Hexagonal¶

Traditional Layered Architecture:

flowchart TB
    UI --> BusinessLogic
    BusinessLogic --> DataAccess

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Each layer calls the next downward.
Hard to swap infrastructure without touching business logic.
Risk of leaking DB entities into UI layer.

Hexagonal Architecture:

flowchart TB
    PrimaryAdapter1 --> PrimaryPort --> CoreDomain
    CoreDomain --> SecondaryPort --> SecondaryAdapter1

Hold "Alt" / "Option" to enable pan & zoom

No direct layer-to-layer coupling.
Core communicates through Ports only.
Infrastructure is completely isolated.

Warning

Layered architectures often cause infrastructure bleeding into business logic.
Hexagonal locks the business inside protective ports.

🧅 Onion Architecture vs Hexagonal¶

Onion Architecture:

flowchart TB
    UI --> ApplicationService --> DomainModel --> Infrastructure

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Clear inward dependencies.
Strong domain core protection.

Hexagonal Architecture:

Same inward dependency rules.
Adds Ports explicitly:
Define how external world interacts with the Core (not just what depends).

✅ Hexagonal = Onion + Ports/Adapters + Stronger boundary contracts.

🧹 Clean Architecture vs Hexagonal¶

Clean Architecture (by Uncle Bob):

Entities and Use Cases at the center.
Interface Adapters around them.
Frameworks (DB, Web, etc.) at the outermost circle.

Hexagonal Architecture:

Same inside-out dependency rule.
Focuses more on dynamic interaction points (Ports/Adapters) than just static layers.

Aspect	Clean Architecture	Hexagonal Architecture
Layering Focus	Static code organization	Interaction flow (ports)
Domain Protection	✅	✅
External Isolation	✅	✅
Emphasis	Policy/Layered Circles	Interaction Points/Boundaries

✅ Hexagonal emphasizes real-world behavior orchestration, making integration points first-class citizens.

🧱 Domain-Driven Design (DDD) and Hexagonal¶

DDD Tactical Patterns:

Entities
Value Objects
Aggregates
Repositories
Domain Events
Application Services

Where Hexagonal Architecture fits:

DDD Tactical Artifact	Hexagonal Placement
Entity, Aggregate, Value Object	Inside Core Domain
Repository Interface	Secondary Port
Application Service (Use Case)	Primary Port
Domain Event Publisher	Secondary Port

✅ Hexagonal is the architecture model that naturally hosts DDD tactical patterns inside bounded, protected cores.

Info

In ConnectSoft SaaS services, every microservice applies Hexagonal Architecture + DDD together.

🌍 Microservices Architecture and Hexagonal¶

Microservices Aspect	Hexagonal Alignment
Bounded Contexts	One Hexagon per microservice.
Independent Deployment	Primary/Secondary Adapters allow different delivery models per service.
Resilience and Evolution	Ports abstract infrastructure changes without touching Core.

✅ Microservices define service-level boundaries;
✅ Hexagonal Architecture defines internal modular boundaries inside each service.

📈 Visual Summary: How Architectures Evolved¶

graph LR
    LayeredArchitecture --> OnionArchitecture
    OnionArchitecture --> CleanArchitecture
    CleanArchitecture --> HexagonalArchitecture

Hold "Alt" / "Option" to enable pan & zoom

✅ Hexagonal is the next evolution, focusing not only on code structure but on system communication flows.

📚 Quick Takeaways¶

Topic	Quick Insight
Hexagonal vs Layered	Ports break rigid vertical coupling.
Hexagonal vs Onion	Adds dynamic Ports/Adapters to static inner/outer layers.
Hexagonal vs Clean	Similar dependency inversion, but Hexagonal elevates dynamic boundaries.
Hexagonal and DDD	Perfectly hosts Entities, Aggregates, Repositories, Use Cases inside.
Hexagonal in Microservices	Forms the inner architecture of every independently deployable service.

🧩 Conclusion¶

At ConnectSoft, Hexagonal Architecture is not a trend — it is a core operating model that ensures our systems are:

🔥 Business-centered, not technology-driven
🔒 Resilient and isolated from infrastructure volatility
🚀 Adaptable to change without heavy refactoring
🔍 Highly testable and observable from day one
🛠️ Cloud-native and microservice-ready at all levels

By enforcing Ports and Adapters boundaries,
we create systems that scale, evolve, and integrate seamlessly with new technologies, frameworks, and platforms —
without touching the domain logic that powers our business.

✅ Whether building a SaaS product, an AI engine, a platform microservice, or a gateway,
✅ Hexagonal Architecture enables ConnectSoft teams to focus on what matters most: the business capabilities we deliver.

🛡️ Hexagonal Architecture (Ports and Adapters)¶

🎯 Introduction¶

🧠 Core Concepts¶

🏛️ Structure Overview¶

🌟 Principles¶

🔗 How It Connects to ConnectSoft’s Platform¶

📋 Summary of Core Concepts¶

🧱 Components of Hexagonal Architecture¶

🧠 Domain Core (Inside the Hexagon)¶

🔗 Ports¶

Primary Ports¶

Secondary Ports¶

🎯 Primary Adapters (Inbound)¶

🎯 Secondary Adapters (Outbound)¶

🧩 Full Component Diagram¶

📋 Component Responsibilities Summary¶

🧱 Layered Structure and Flow in Hexagonal Architecture¶

🧩 Logical Layering¶

🔀 Dependency Rules¶

🔥 Flow of Execution¶

🧠 C# Code Example: Full Flow¶

1. Primary Port (Use Case Interface)¶

2. Domain Core Implementation (Use Case)¶

3. Secondary Port (Repository Interface)¶

4. Secondary Adapter (Infrastructure)¶

5. Primary Adapter (REST Controller)¶

📚 Layered Mapping Summary¶

🌟 Best Practices for Layering at ConnectSoft¶

🌟 Benefits and Trade-Offs of Hexagonal Architecture¶

✅ Key Benefits¶

📈 Diagram: Benefits Mapping¶

⚠️ Trade-Offs and Challenges¶

🔥 Example of Complexity¶

🧠 Best Practices to Maximize Benefits at ConnectSoft¶

📋 Benefit vs Trade-Off Summary Table¶

🧩 ConnectSoft Hexagonal Architecture Blueprint¶

🏛️ Platform-Wide Application of Hexagonal Principles¶

📚 ConnectSoft Example: SaaS Service Hexagon¶

🛠️ Sample Hexagonal Use Case: Tenant Registration¶

Primary Port¶

Domain Service (Use Case Implementation)¶

Secondary Ports¶

Secondary Adapters¶

🌍 Blueprint: Across ConnectSoft Ecosystem¶

🔗 Hexagonal Across Event-Driven Workflows¶

📋 ConnectSoft Hexagonal Blueprint Principles¶

📦 Real-World Use Cases of Hexagonal Architecture at ConnectSoft¶

🛍️ E-Commerce Microservice: Order Management¶

📖 Scenario¶

🧠 Structure¶

🛠️ Flow Diagram¶

🧩 Key Best Practices¶

🤖 AI Workflow Orchestration Service¶

📖 Scenario¶

🧠 Structure¶

🛠️ Flow Diagram¶

🧩 Key Best Practices¶

📡 Event-Driven Inventory Service¶

📖 Scenario¶

🧠 Structure¶

🛠️ Flow Diagram¶

🧩 Key Best Practices¶

📚 Recap: Best Practices for Hexagonal Use Cases¶

🧠 Hexagonal Architecture vs Other Architectural Styles¶

📚 High-Level Comparison Table¶

🏛️ Layered Architecture vs Hexagonal¶

🧅 Onion Architecture vs Hexagonal¶

🧹 Clean Architecture vs Hexagonal¶

🧱 Domain-Driven Design (DDD) and Hexagonal¶

🌍 Microservices Architecture and Hexagonal¶

📈 Visual Summary: How Architectures Evolved¶

📚 Quick Takeaways¶

🧩 Conclusion¶

📚 References¶

📖 Internal ConnectSoft Documentation¶

📖 External References¶