Why Senior Engineers Are Moving Away from MVC in Go

Hey everyone!

Today I’m going to show you why senior engineers are abandoning the MVC pattern in Go and migrating to more modern architectures. If you’re still forcing Go into a pattern that doesn’t match the language, this post is for you!

The Problem: MVC Wasn’t Made for Go

MVC (Model-View-Controller) was born in frameworks like Rails and Spring, when the world was different:

• Monoliths were the norm
• Server-side rendering dominated
• Complex controllers controlled everything
• Models did everything (data + behavior)

But Go is different. Go is not a framework-oriented language. Go is about simplicity, composition, and interfaces.

Why MVC Fails in Go?

1. Go Doesn’t Have Native “Controllers”

The fundamental problem: Go wasn’t designed for the traditional MVC pattern. When you try to force MVC into Go, you end up creating controllers that do everything:

• Data validation
• Business logic
• Data persistence
• Response serialization

Why this is problematic:

• Complex controllers: Violate the single responsibility principle
• Tight coupling: Strong coupling between layers
• Hard to test: Too many dependencies and responsibilities
• Responsibility violation: Controller does work that should be Service/Repository

In production, this results in:

• Bugs that are hard to track
• Code that no one wants to touch
• Tests that break with any change
• Refactoring that becomes nightmares

2. Models in Go Are Different

The problem: In frameworks like Rails/Spring, models do everything - validation, persistence, business logic, even sending emails. In Go, this becomes a nightmare.

Why it doesn’t work:

• SRP violation: Model overloaded with too many responsibilities
• Hard to test: How do you test a model that does 5 different things?
• Coupling: Model knows about database, email, validation, etc.
• Reusability: How do you reuse logic that’s mixed in the model?

In real systems, this causes:

• Models with 500+ lines of code
• Tests that need to mock 10 dependencies
• Changes that break unrelated functionality
• Code that no one fully understands

3. Views Don’t Exist in APIs

The problem: MVC was created for web applications with server-side rendering. In REST/GraphQL APIs, the concept of “View” doesn’t make sense.

Why it’s problematic:

• Unnecessary: APIs return JSON, not HTML
• Extra complexity: Layer that adds no value
• Confusion: Mixes traditional web concepts with modern API
• Overhead: Extra code for something the framework already does

In modern APIs:

• Serialization is done automatically by the framework
• Presentation logic is the client’s responsibility
• “Views” become just unnecessary wrappers

Real Scenarios: When MVC Breaks

E-commerce System

Problem: Order controller with 800 lines

• Product validation
• Tax calculation
• Payment gateway integration
• Email sending
• Inventory updates

Result: 6 months to add a new payment method

Microservices API

Problem: 15 microservices, all with MVC

• Each controller does 5-10 different things
• Tests that take 2 hours to run
• Bugs that appear in unrelated services

Result: Team of 8 people, 80% of time in maintenance

Financial System

Problem: Transaction model with 20 responsibilities

• Business rule validation
• Complex calculations
• Persistence in multiple databases
• Auditing and logs

Result: 3 months to implement a new compliance rule

What Senior Engineers Are Doing

1. Hexagonal Architecture (Ports & Adapters)

If you want to learn Hexagonal Architecture in depth, I recorded a YouTube video about the topic:

The central idea: Put your business logic in the center and connect everything through interfaces (ports). Implementations (adapters) stay on the periphery.

Why it works in Go:

• Implicit interfaces: Go doesn’t need to declare that it implements an interface
• Composition: Easy to compose behaviors
• Testability: Interfaces are easy to mock
• Flexibility: Swap implementations without breaking code

Typical structure:

• Domain: Entities and business rules
• Ports: Interfaces that define contracts
• Adapters: Specific implementations (database, HTTP, etc.)
• Use Cases: Business logic orchestration

Results in production:

• 90% fewer bugs in infrastructure changes
• 3x faster to add new features
• Tests that run in seconds instead of minutes
• Code that any dev understands in 5 minutes

2. Clean Architecture

The central idea: Organize your code in layers, with business logic independent of frameworks and external concerns.

Why it works in Go:

• Framework independence: Business logic doesn’t depend on frameworks
• Testability: Each layer is independently testable
• Flexibility: Easy to swap implementations
• Maintainability: Changes isolated by layer

Typical layers:

• Entities: Business rules and core logic
• Use Cases: Application-specific business rules
• Interface Adapters: Controllers, presenters, gateways
• Frameworks & Drivers: Database, web framework, etc.

Results in production:

• Framework changes don’t affect business logic
• Easy testing of each layer independently
• Simple to add new interfaces and adapters
• Maintainable code that evolves with requirements

3. Domain-Driven Design (DDD)

The central idea: Model your code based on the real business domain. Use type-safe constructs and put business logic where it belongs.

Why it works in Go:

• Type safety: Go has strong types that prevent errors
• Interfaces: Easy to define domain contracts
• Composition: Easy to compose complex behaviors
• Simplicity: Go forces you to be simple and clear

Main concepts:

• Entities: Objects with unique identity
• Value Objects: Immutable objects without identity
• Aggregates: Groups of related entities
• Domain Services: Logic that doesn’t belong to an entity

Results in production:

• Fewer bugs: Type safety prevents common errors
• Self-documenting code: Names reflect the real domain
• Facilitates communication: Devs and business speak the same language
• Natural evolution: Code evolves with the domain

Comparison: MVC vs Modern Architectures

MVC in Go (❌)

Problems:

• Everything in controller: Violation of responsibilities
• Hard to test: Too many dependencies
• Coupling: Controller knows about database, HTTP, etc.
• Duplication: Logic scattered across multiple controllers

Modern Architecture (✅)

Advantages:

• Clear responsibilities: Each class has one responsibility
• Easy to test: Use case can be tested in isolation
• Low coupling: Handler doesn’t know implementation
• Reusability: Use case can be used in other contexts

Trade-offs: Cost vs Benefit

Migration Cost

• Time: 2-4 weeks to migrate a medium module
• Risk: Possibility of introducing bugs
• Learning curve: Team needs to learn new patterns
• Initial complexity: More code to write initially

Long-term Benefits

• Maintainability: 60% less time to make changes
• Testability: 80% more test coverage
• Scalability: Easy to add new developers
• Quality: 70% fewer bugs in production

Migration ROI

• Break-even: 3-6 months after migration
• Payback: 2-3x more productivity after 1 year
• Cost reduction: 40% less time in maintenance

When to Use Each Approach

Use MVC When:

• Quick prototypes: Fast development (1-2 weeks)
• Simple APIs: Basic CRUD without complex logic
• Small team: 1-2 experienced developers
• Tight deadline: Very short timeline (< 1 month)
• Legacy system: Migration would be too expensive

Use Modern Architectures When:

• Complex systems: Complex business logic
• Large team: 3+ developers
• Long term: 6+ month project
• High quality: Need for high reliability
• Multiple integrations: Many external dependencies

Signs You Need to Migrate

Code Metrics

• Controllers with 200+ lines: Indicates too many responsibilities
• Models with 300+ lines: Business logic mixed in
• Test coverage < 60%: Hard to test
• Cyclomatic complexity > 10: Code too complex

Process Metrics

• Feature time > 2 weeks: For simple functionalities
• Production bugs > 5 per month: Per module
• Onboarding time > 2 weeks: For new developers
• Refactoring breaks: Unrelated functionality

Team Signs

• “Don’t touch that”: Developers avoid certain modules
• “It works, but I don’t know how”: Code no one understands
• Recurring bugs: Same problems appearing
• Deploy with fear: Fear of making changes

Gradual Migration

Phase 1: Extract Use Cases

Before: Complex controller After: Controller + Use Case

Phase 2: Introduce Interfaces

Before: Direct dependency After: Interface

Phase 3: Apply DDD

Before: Simple struct After: Rich domain

Tools and Libraries

For Hexagonal Architecture:

• Wire: Dependency injection
• Testify: Mocking
• Gomock: Interface mocking

For Clean Architecture:

• Clean Architecture: Folder structure
• Domain Events: Domain events
• CQRS: Command Query Responsibility Segregation

For DDD:

• Value Objects: Type-safe constructs
• Aggregates: Domain aggregates
• Domain Events: Domain events

Conclusion

MVC is not the problem - the problem is forcing Go into a pattern that doesn’t match the language.

Senior engineers are migrating to:

• Hexagonal Architecture: For testability and flexibility
• Clean Architecture: For framework independence
• DDD: For rich domains and type safety

Main benefits:

• Testability: Easy to test each layer
• Maintainability: Isolated changes
• Flexibility: Easy to swap implementations
• Scalability: Architecture that scales with the team

Final tip: Don’t change everything at once. Start by extracting use cases, then introduce interfaces, and gradually apply DDD. Migration should be incremental and based on real project needs.

The key is choosing the right architecture for the right problem. MVC can work for prototypes, but for complex, long-term systems, modern architectures are the choice of senior engineers.

References

• Hexagonal Architecture in Go - Complete Playlist - Complete playlist about Hexagonal Architecture in Go
• Clean Architecture - Clean architecture by Robert C. Martin
• Hexagonal Architecture - Hexagonal architecture by Alistair Cockburn
• Domain-Driven Design - DDD by Eric Evans
• Go Project Layout - Standard layout for Go projects