Agent Skills: Replit Production Checklist

Replit Production Checklist

Overview

Complete checklist for deploying Replit apps to production using Autoscale or Reserved VM deployments. Covers configuration, secrets, health checks, custom domains, rollback procedures, and monitoring.

Prerequisites

• Replit Core, Pro, or Teams plan (deployment access)
• App tested and working in Workspace
• PostgreSQL database provisioned (if needed)
• Custom domain (optional) with DNS access

Production Deployment Checklist

Phase 1: Configuration

• [ ] .replit deployment section configured:

[deployment]
run = ["sh", "-c", "npm start"]
build = ["sh", "-c", "npm ci --production && npm run build"]
deploymentTarget = "autoscale"  # or "cloudrun" for Reserved VM

• [ ] replit.nix includes only required system packages (trim dev-only deps)
• [ ] NODE_ENV set to "production" in .replit env section
• [ ] Port reads from process.env.PORT

Phase 2: Secrets

• [ ] All secrets configured in Replit Secrets tab
• [ ] Secrets sync enabled (Workspace <-> Deployment)
• [ ] No hardcoded credentials in source code
• [ ] Startup validates all required secrets:

const REQUIRED = ['DATABASE_URL', 'JWT_SECRET'];
const missing = REQUIRED.filter(k => !process.env[k]);
if (missing.length) {
  console.error(`FATAL: Missing secrets: ${missing.join(', ')}`);
  process.exit(1);
}

Phase 3: Health Check

• [ ] /health endpoint exists and checks dependencies:

app.get('/health', async (req, res) => {
  const checks = {
    db: false,
    uptime: process.uptime(),
    memory: Math.round(process.memoryUsage().heapUsed / 1024 / 1024),
  };

  try {
    await pool.query('SELECT 1');
    checks.db = true;
  } catch {}

  const status = checks.db ? 200 : 503;
  res.status(status).json({ status: status === 200 ? 'healthy' : 'degraded', ...checks });
});

• [ ] Health endpoint does NOT expose secrets or internal paths
• [ ] Health endpoint responds within 5 seconds

Phase 4: Error Handling

• [ ] Global error handler catches uncaught exceptions:

// Never expose stack traces in production
app.use((err: Error, req: Request, res: Response, next: NextFunction) => {
  console.error('Unhandled error:', err.message);
  res.status(500).json({
    error: process.env.NODE_ENV === 'production'
      ? 'Internal server error'
      : err.message,
  });
});

process.on('uncaughtException', (err) => {
  console.error('Uncaught exception:', err.message);
  process.exit(1);
});

process.on('unhandledRejection', (reason) => {
  console.error('Unhandled rejection:', reason);
});

• [ ] Rate limiting on public endpoints
• [ ] Input validation on all user data (Zod, Joi, or manual)

Phase 5: Deploy

Via Replit UI:

1. Click "Deploy" button in top bar
2. Choose type:
   • Static: Frontend-only (HTML/CSS/JS), free
   • Autoscale: Scales to zero, pay per request (best for variable traffic)
   • Reserved VM: Always-on, fixed cost (best for consistent traffic)
3. Select machine size (0.25-8 vCPU)
4. Click "Deploy"

Via .replit config (automatic on push):

[deployment]
run = ["sh", "-c", "node dist/index.js"]
build = ["sh", "-c", "npm ci --production && npm run build"]
deploymentTarget = "autoscale"

Phase 6: Custom Domain

1. Deployment Settings > Custom Domain
2. Enter domain: app.example.com
3. Add DNS record at your registrar:
   CNAME: app -> your-repl-slug.replit.app
4. Wait 1-5 minutes for SSL auto-provisioning
5. Verify: curl -I https://app.example.com

For Replit-purchased domains: manage DNS directly in Replit dashboard.

Phase 7: Post-Deploy Verification

set -euo pipefail
DEPLOY_URL="https://your-app.replit.app"

# Health check
curl -sf "$DEPLOY_URL/health" | jq .

# Response time
curl -s -o /dev/null -w "HTTP %{http_code}, %{time_total}s\n" "$DEPLOY_URL/"

# Headers check
curl -sI "$DEPLOY_URL" | grep -iE "(server|content-type|x-)"

Phase 8: Rollback Plan

Replit Deployments support one-click rollback to any previous successful deployment:

1. Go to Deployment Settings > History
2. Find the last known-good deployment
3. Click "Rollback to this version"
4. Verify health endpoint after rollback

Monitoring Recommendations

| Signal | Warning | Critical | |--------|---------|----------| | Health check | 1 failure | 3 consecutive failures | | Response time (p95) | > 2s | > 5s | | Error rate | > 1% | > 5% | | Memory usage | > 75% of limit | > 90% | | Cold start (Autoscale) | > 5s | > 15s |

Error Handling

| Issue | Cause | Solution | |-------|-------|----------| | Deploy fails at build | Missing dependency | Check build logs, ensure npm ci works | | 503 after deploy | App crashing on start | Check deployment logs, verify secrets | | Cold start too slow | Heavy imports | Lazy-load non-critical modules | | Custom domain not working | DNS not propagated | Wait or verify CNAME record |

Resources

• Replit Deployments
• Deployment Rollbacks
• Custom Domains
• Replit Status

Next Steps

For version upgrades, see replit-upgrade-migration.