TypeScript End-to-End

StackSwap uses TypeScript in strict mode across every layer: React components, API routes, server-only modules (`lib/server/*`), and the Supabase access layer. Shared types (e.g. StackscanReport, StackTransformationPlanRow, VerdictRow) live in `lib/` and are imported by both the UI and the API/worker code, so the same contract describes a report whether it is being written to Supabase, rendered in a component, or returned from a JSON endpoint.

Because every boundary is typed, a schema change in the StackScan pipeline propagates to the UI, paid results page, and API at compile time. Types for intake, verdicts, and recommendations flow through `scanStack()` → `verdictsToToolSavingsRows()` → `buildStackTransformationPlanRows()` → `applyLlmRecommendationsToRows()` without `any` escape hatches. Branded types (report ids, tool names) catch misuses that would otherwise only surface at runtime.

Strict, end-to-end TypeScript is the safety net that lets StackSwap ship large refactors (adding paid results, wiring Stripe, rebuilding intake) without a fleet of manual regression tests. The type system is the first reviewer on every change.