How Deep Is the Logic Behind an Endpoint?
Spoiler: Swagger Won’t Tell You
When developers and architects examine a REST API, they often turn to the Swagger (OpenAPI) documentation to understand how the system works. Endpoints are listed with methods, parameters, and expected responses. It’s clean, standardized, and comforting.
But it’s also deceptive.
The Illusion of Simplicity
Looking at an endpoint like:
POST /orders/submitmight suggest a straightforward action — you send an order, the system confirms.
But what actually happens behind that single call could be a cascade of:
dozens of domain events,
database writes,
orchestrations between bounded contexts,
external service calls,
and conditional business rules or complex calculation logic (think pricing rules, tax policies, discount hierarchies).
Swagger shows you the surface, but not the depth.
The Question We Should Be Asking
Instead of just:
“What does this endpoint do?”
We should be asking:
“How much happens when this endpoint is called?”
Event Storming: Making the Invisible Visible
One powerful approach is Event Storming (Process Level). It reveals the business logic as a flow of domain events triggered by a command.
For the submit order example, a storming session might uncover:
OrderValidatedStockReservedPaymentAuthorizedInvoiceGeneratedCustomerNotifiedOrderMarkedForShipping
Each event reveals another layer of logic hiding behind the endpoint.
Now you understand a bit more the real cost of calling it.
The Limits of Sticky Notes
Event Storming is fantastic for uncovering process complexity. But it has its drawbacks - it is a manual, relatively long workshop and in addition it often misses one crucial category:
👉 Calculation-heavy logic.
Pricing rules, discount conditions, tax computations, dynamic offers — all the logic that doesn’t show up as discrete events, but can be deeply nested and highly conditional.
Event Storming doesn't show you how complex it is to calculate a price or apply a loyalty discount. It shows the "when," not the "how."
Where Noesis Excels
This is where Noesis comes in. Our fully automatic tool uses static code analysis and a structured P3 model (Three perspectives - Domain, Technology, People) to:
show the key building blocks responsible for the implementation and how they depend on each other
expose how they are organized in modules,
include documentation pages with more detailed diagrams and descriptions, that go way beyond what Swagger or sticky notes can capture.
Here's an example what you can see after clicking a link in Swagger you are brought to this visualization showing the logic depth behind placing an order:
Why This Matters
For developers: you can understand and implement faster
For architects: you can gain more control and take better more informed decisions.
For analysts: you can verify processes in the codebase, without guesswork.
For support engineers: you can faster understand impact of defects.
Fewer assumptions.
Fewer bugs.
Fewer production surprises.
🚀 See what’s really behind your endpoints
Check out Noesis at: https://noesis.vision and/or subscribe to the updates below 👇