Understanding how frontend systems evolve under pressure.
Most frontend systems do not begin with architecture. They begin with delivery.
Systems rarely fail because of patterns.
They fail because prior decisions stop holding under new pressure.
The domain is protected. The state is centralized.
But deployments are no longer synchronized.
When systems evolve independently, assumptions become liabilities.
Deployment Mode: Coordinated
Frontend bundle: v1
Backend contract: v1
Total rendered: 110
Backend v2 renames total → amount.
Frontend still expects data.total. Rendering fails silently.
No compile-time error. No deployment coordination. Failure only visible at runtime.
CI/CD increases velocity — but introduces temporal coupling.
Backward compatibility is now mandatory. Contracts must evolve safely.
After independent deployment, compatibility is a survival constraint.
// Backend v1
{ total: 110 }
// Backend v2
{ amount: 110 }
// Frontend still expects:
data.total