You’ve probably heard the hype: hexagonal architecture promises cleaner code, better testability, and future-proof systems. But when you actually try implementing those ports and adapters, it feels like building a spaceship to cross the street. I’ve been there—staring at endless abstraction layers, wondering if my “clean” code had become a textbook example of over-engineering.
Let’s cut through the noise.
The Double-Edged Sword of Structure
Hexagonal architecture isn’t broken. We just keep using it wrong.
Think of it like a Swiss Army knife: brilliant when you need specific tools, but ridiculous if you’re just opening a yogurt. The pattern’s critics aren’t wrong—I’ve seen teams drown in UserMapperFactoryAdapter classes for apps smaller than a Twitter thread. But here’s what nobody tells you: the real power lies in knowing what not to build.
Why We Keep Shooting Ourselves in the Foot
Let’s name the elephants in the room:
- The “Template Terror”: Most tutorials show hexagonal architecture with 12 layers because… well, that’s how they learned it. Nobody needs a separate DTO, domain model, and entity for a to-do list app.
- The Copy-Paste Trap: We cargo-cult patterns from enterprise systems into projects where they’re as useful as a snowplow in Hawaii.
- The Boundary Obsession: Yes, explicit interfaces matter. No, you don’t need a unique adapter for every third-party API that’ll retire next quarter.
A startup client once showed me their “perfectly hexagonal” e-commerce platform. It had 23 modules. They’d pivoted to selling digital stickers two months prior.
Keep the Baby, Ditch the Bathwater
Three non-negotiable principles—and where everyone overcomplicates them:
| Core Idea | What We Usually Do | What Actually Works |
|---|---|---|
| Business logic isolation | Create 5 layers of DTOs | Forbid domain entities from importing ANY framework |
| Dependency inversion | Write adapters for every API | Mock third-party services at the HTTP layer |
| Testability | Mock all 17 dependencies | Test domain logic with zero frameworks |
Here’s the golden rule I stole from a fintech architect: “If your tests need Spring to run, you’ve already lost.”
Practical Simplification Tactics (That Won’t Bite You Later)
1. The Lazy Adapter Strategy
Need to integrate Stripe and PayPal? Instead of building two adapters:
“`python
Shared payment port
class PaymentProvider:
def charge(self, amount: float) -> PaymentResult:
raise NotImplementedError
Single adapter with routing
class HybridPaymentAdapter(PaymentProvider):
def init(self, stripe_client, paypal_client):
self.providers = {
“stripe”: stripe_client,
“paypal”: paypal_client
}
def charge(self, provider_type: str, amount: float) -> PaymentResult:
return self.providers[provider_type].process(amount) “`
This violates “pure” hexagonal dogma. It also saves 300 lines of code and hours of debugging.
2. The Framework Friendliness Test
Ask yourself: “Could I replace my web framework in a week?” If yes, your boundaries are clean. If no—but you’re using FastAPI’s magic dependency injection everywhere—that’s okay! Just contain it to API routes.
3. The 80/20 Rule for Test Coverage
A SaaS client reduced testing time by 70% with this approach:
- Domain layer: 100% unit test coverage, no mocks
- Adapters: Contract tests verifying inputs/outputs
- UI/APIs: Only test critical happy paths
They kept deployment pipelines fast while catching 93% of bugs pre-production.
When to Bend (or Break) the Rules
- Prototypes/POCs: Build a “hexagonal-ish” core. Hardcode databases. Refactor when (if) the project survives.
- Legacy Integration: Wrap entire subsystems as single adapters instead of rewriting.
- Tiny Services: Skip ports for non-critical features. Your cat photo API doesn’t need Kafka adapters.
A common mistake: applying the pattern uniformly. Hexagonal architecture shines when protecting valuable, evolving business logic—not for every CRUD endpoint.
The Art of Strategic Complexity
The pattern’s critics miss a crucial point: accidental complexity comes from misapplication, not the architecture itself. By focusing on:
- Tooling: Use codegen tools (think OpenAPI generators) for boilerplate adapters
- Selective Isolation: Only decouple dependencies likely to change
- Architectural Debt Tracking: Log technical debt explicitly when taking shortcuts
You gain the pattern’s benefits without the dreaded “Java Enterprise Sample Project” effect.
Your Decision Framework
Still unsure? Ask these questions:
- How often do our dependencies change?
- Is our domain logic complex enough to justify isolation?
- Are we willing to delete code?
If you answered “rarely,” “no,” or “delete code?!,” consider a simpler layered architecture. That’s not failure—it’s pragmatism.
Final Thought: It’s About Tradeoffs, Not Perfection
I once helped a team “de-hexagonize” 40% of their codebase. Their CTO panicked until deployment times dropped from 18 minutes to 4. Hexagonal architecture isn’t a religion—it’s a tool. Use it where it matters, cheat where it doesn’t, and always keep a refactoring escape hatch.
After all, the best architectures are the ones that let you say, “We changed our minds” without tears.
