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explore / Web & frontend / mozg / Next.js App Router

Next.js · Guides

Answer questions from the Next.js guides: authentication, caching, data fetching patterns, migration, deployment and testing.

1,378 notes · updated 2026-08-05 · trained 89%

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> use mozg/nextjs-guides — …
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Ask it things like

answers 25/28 on its latest exam · anti-bluff 1/2
What should I do to re-verify user permissions inside a Server Action that modifies data?Authentication & Server Actions✓
What is the Data Access Layer pattern and why is it recommended?Data Access Patterns✓
How do I ensure a Server Action prevents CSRF attacks?Authentication & Server Actions✓
Why are closure variables in Server Actions automatically encrypted?Authentication & Server Actions✓
How do I prevent IDOR (Insecure Direct Object Reference) vulnerabilities in my application?Authorization & Access Control✓
What is the difference between time-based and on-demand ISR revalidation?Caching & Revalidation✓
Can I use environment variables directly in a Client Component?Data Access Patterns✓
Before passing data from a Server Component to a Client Component, what must I do?Data Security & Sanitization✓

What it can answer

28 checks
89%
✓Caching & Revalidation4 / 4
✓Data Access Patterns4 / 4
▲Authentication & Server Actions3 / 4
✓Data Security & Sanitization3 / 3
✓Deployment & Infrastructure2 / 2
✓Input Validation2 / 2
▲Next.js 16 Migration2 / 3
▲Security Headers & CSP2 / 3
✓Testing & Debugging2 / 2
✓Authorization & Access Control1 / 1
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Inside

  • NEXT_PUBLIC_ variables are frozen at build time · deployment
  • Environment variable load order · deployment
  • .env files should not be committed to version control · deployment
  • Variable referencing in .env files · deployment
  • Loading environment variables outside Next.js runtime with @next/env · deployment
  • .env.test.local should not be committed but .env.test should be · deployment
  • Loading environment variables from .env files · deployment
  • NEXT_PUBLIC_ prefix for browser-accessible environment variables · deployment
  • Multiline environment variables in .env files · deployment
  • .env file location with /src directory · deployment
  • Dynamic lookups of environment variables are not inlined · deployment
  • Runtime environment variables in dynamic rendering · deployment
  • Test environment variables with .env.test · deployment
  • Default NODE_ENV values in Next.js · deployment

Licence

CC BY-NC-SA 4.0

Use it, copy it, build on it, with credit. Selling it is not allowed.