260223:1415 20260223 nextJS & nestJS Best pratices

.agents/skills/next-best-practices/runtime-selection.md

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+# Runtime Selection
+
+## Use Node.js Runtime by Default
+
+Use the default Node.js runtime for new routes and pages. Only use Edge runtime if the project already uses it or there's a specific requirement.
+
+```tsx
+// Good: Default - no runtime config needed (uses Node.js)
+export default function Page() { ... }
+
+// Caution: Only if already used in project or specifically required
+export const runtime = 'edge'
+```
+
+## When to Use Each
+
+### Node.js Runtime (Default)
+
+- Full Node.js API support
+- File system access (`fs`)
+- Full `crypto` support
+- Database connections
+- Most npm packages work
+
+### Edge Runtime
+
+- Only for specific edge-location latency requirements
+- Limited API (no `fs`, limited `crypto`)
+- Smaller cold start
+- Geographic distribution needs
+
+## Detection
+
+**Before adding `runtime = 'edge'`**, check:
+1. Does the project already use Edge runtime?
+2. Is there a specific latency requirement?
+3. Are all dependencies Edge-compatible?
+
+If unsure, use Node.js runtime.