🌐 Netlify Deploy: Pre-flight check and deploy to Netlify...

Validates build config, redirects, environment variables, and deployment readiness for Netlify static/SPA hosting.

Activation

When this skill activates, output:

🌐 Netlify Deploy: Running pre-flight checks...

Then execute the protocol below.

Context	Status
User says "deploy to netlify" or "netlify deploy"	ACTIVE
User says "deploy frontend" or "deploy static site"	ACTIVE
Preparing a React/Vue/Svelte/Next.js static export for hosting	ACTIVE
Deploying a backend service or API server	DORMANT: use railway-deploy
Discussing Netlify pricing or features generally	DORMANT

Anti-patterns

Trap	Reality Check
"I'll configure it in the Netlify UI"	netlify.toml is version-controlled and portable. UI settings get lost across teams.
"Redirects work fine without _redirects"	SPA routing breaks on refresh without /* /index.html 200. Every SPA needs this.
"Environment vars are the same everywhere"	Build-time vars (baked into JS bundle) vs runtime vars (Netlify Functions) are different. NEXT_PUBLIC_ prefix exposes to client.
"The API proxy just works"	/api/* redirects must point to your actual backend URL. Forgetting to update after backend redeploy breaks the frontend.
"I'll check the deploy after pushing"	netlify deploy --build locally catches build failures before they hit production. Always build locally first.

Protocol

Step 1: Check Build Configuration

Look for Netlify config and verify build settings:

# Check for Netlify configuration
ls netlify.toml _redirects _headers 2>/dev/null

# Check package.json for build script
cat package.json | grep -A2 '"scripts"' | grep '"build"'

If netlify.toml exists, verify it:

# Expected structure
[build]
  command = "npm run build"    # or "yarn build", "pnpm build"
  publish = "dist"             # or "build", "out", ".next" (varies by framework)

[build.environment]
  NODE_VERSION = "20"          # Pin Node version for reproducible builds

Framework	Build Command	Publish Directory
React (CRA)	npm run build	build
React (Vite)	npm run build	dist
Next.js (static)	next build && next export	out
Vue	npm run build	dist
Svelte/SvelteKit	npm run build	build
Astro	npm run build	dist
Plain HTML	none	. or public

Flag if: netlify.toml missing or publish directory doesn't match framework default.

Step 2: Verify Redirects and API Proxy

# Check redirect files
cat netlify.toml 2>/dev/null | grep -A5 '\[\[redirects\]\]'
cat _redirects 2>/dev/null

Check for the API proxy pattern (frontend → backend):

# netlify.toml, API proxy to Railway/external backend
[[redirects]]
  from = "/api/*"
  to = "https://your-backend.up.railway.app/api/:splat"
  status = 200
  force = true

Or in _redirects:

/api/*  https://your-backend.up.railway.app/api/:splat  200

Verify:

• ✅ Backend URL is the production URL (not localhost)
• ✅ status = 200 (proxy, not redirect, preserves the URL for the client)
• ✅ force = true if the proxy should override static files at the same path
• ❌ Backend URL still points to localhost:3000: update to production

Flag if: Code references /api/ paths but no proxy redirect is configured.

Step 3: Verify SPA Routing

Single-page apps need a catch-all redirect so deep links and page refreshes work:

# Check for SPA redirect
grep -r "\/\*.*\/index\.html\|\/\*.*200" netlify.toml _redirects 2>/dev/null

Required for SPAs (React Router, Vue Router, etc.):

# In _redirects (must be LAST rule, order matters)
/*  /index.html  200

Or in netlify.toml:

[[redirects]]
  from = "/*"
  to = "/index.html"
  status = 200

Flag if: Project uses client-side routing but no catch-all redirect exists. Symptoms: pages work when navigated to via links, but return 404 on direct URL access or refresh.

Note: Next.js static export handles this differently. Each page is pre-rendered as its own HTML file. SPA redirect is NOT needed for static Next.js.

Step 4: Verify Environment Variables

# Find env vars used in frontend code
grep -rn "process\.env\.\|import\.meta\.env\.\|VITE_\|NEXT_PUBLIC_\|REACT_APP_" --include="*.ts" --include="*.tsx" --include="*.js" --include="*.jsx" . | grep -v node_modules

Build-time vs runtime separation:

Prefix	Framework	When Available	Exposed to Client?
REACT_APP_	CRA	Build time	⚠️ YES: baked into JS bundle
NEXT_PUBLIC_	Next.js	Build time	⚠️ YES: baked into JS bundle
VITE_	Vite	Build time	⚠️ YES: baked into JS bundle
No prefix	Any	Build time only	❌ No, server-side/build scripts only

Critical security check:

# Search for secrets that might be exposed to client
grep -rn "NEXT_PUBLIC_.*SECRET\|NEXT_PUBLIC_.*KEY\|VITE_.*SECRET\|REACT_APP_.*SECRET" --include="*.ts" --include="*.tsx" --include="*.js" --include="*.env*" . | grep -v node_modules

Flag if: Any secret (API keys with write access, database URLs, auth secrets) uses a client-exposed prefix. These are baked into the JavaScript bundle and visible to anyone who opens DevTools.

Output: List each variable with where to set it:

• Netlify UI: Site Settings → Environment Variables (for secrets)
• netlify.toml [build.environment] (for non-sensitive build config like NODE_VERSION)

Step 5: Check Custom Domain and SSL

# Check for domain configuration
cat netlify.toml 2>/dev/null | grep -A5 '\[context\]'

Verify in Netlify dashboard:

• ✅ Custom domain added (Domain Management → Add domain)
• ✅ DNS points to Netlify (CNAME to *.netlify.app or A record to Netlify load balancer)
• ✅ SSL certificate provisioned (automatic via Let's Encrypt: check HTTPS section)
• ✅ Force HTTPS enabled (redirects http → https)
• ✅ www redirect configured (www → apex or apex → www: pick one, be consistent)

Flag if: Domain is added but DNS hasn't propagated or SSL shows "Waiting for DNS verification."

Step 6: Check for Netlify Functions

# Check for serverless functions
ls netlify/functions/ functions/ 2>/dev/null
cat netlify.toml 2>/dev/null | grep 'functions'

If functions exist, verify:

• Function directory is specified in netlify.toml: [functions] directory = "netlify/functions"
• Functions have correct export pattern: export const handler = async (event, context) => { ... }
• Environment variables needed by functions are set in Netlify dashboard (these are runtime, not build-time)
• Functions are not importing large dependencies that exceed Netlify's 50MB bundle limit

Step 7: Check Headers Configuration

# Check for security headers
cat netlify.toml 2>/dev/null | grep -A10 '\[\[headers\]\]'
cat _headers 2>/dev/null

Recommended security headers:

# netlify.toml
[[headers]]
  for = "/*"
  [headers.values]
    X-Frame-Options = "DENY"
    X-Content-Type-Options = "nosniff"
    Referrer-Policy = "strict-origin-when-cross-origin"
    Permissions-Policy = "camera=(), microphone=(), geolocation=()"

Step 8: Pre-Deploy Checklist

Build locally to catch errors before Netlify builds:

# Local build test
npm run build

# Check output directory exists and has content
ls -la dist/  # or build/, out/, etc.

# Check for common issues
grep -rn "http://localhost\|http://127\.0\.0\.1" dist/ 2>/dev/null

Check	Command	Pass Criteria
Build passes	npm run build	Exit code 0, no errors
Output directory exists	ls dist/	Has index.html and assets
No localhost in build	grep dist/ for localhost	Zero matches
_redirects in output	ls dist/_redirects	Exists if using _redirects approach
Env vars documented	Check .env.example	All client vars listed
No secrets in client code	grep for exposed secrets	Zero matches
Git clean	git status	All changes committed

Output pre-deploy summary:

🌐 Netlify Deploy: Pre-flight Complete

Project: [name] ([framework])
Build: ✅ passes → [publish directory]
Redirects: ✅ SPA routing + API proxy configured
Env vars: ✅ 8 build-time vars, no secrets exposed
Domain: ✅ [domain] with SSL
Functions: ✅ 2 functions in netlify/functions/
Headers: ✅ security headers configured

Ready to deploy.
  Preview:    netlify deploy --build
  Production: netlify deploy --build --prod

Step 9: Post-Deploy Verification

After deployment completes:

1. Preview deploy: Netlify generates a unique URL for every deploy: test there first
2. Check build log: Netlify dashboard → Deploys → click deploy → Build Log
3. Test SPA routing: Navigate directly to a deep route (e.g., /dashboard/settings): should load, not 404
4. Test API proxy: Open DevTools Network tab, trigger an API call, verify it reaches backend
5. Check SSL: Visit https://[domain], padlock should appear, no mixed content warnings
6. Test redirects: Visit http://[domain]: should redirect to https://

Rollback plan:

• Netlify keeps every deploy as an immutable snapshot
• Dashboard → Deploys → click any previous deploy → "Publish deploy"
• Instant rollback, no rebuild required

Level History

• Lv.1: Base: Build config validation, redirect/proxy verification, SPA routing, env var security audit, domain/SSL checks, Netlify Functions, security headers, pre/post-deploy checklists. Based on AdminStack marketing site, GreenAcres frontend, and other Netlify deployments. (Origin: MemStack Pro v3.2, Mar 2026)