HTTP 301 Moved Permanently — SEO Redirects & Best Practices

When to Return 301

Use for permanent URL changes: domain migrations, URL restructuring, HTTP → HTTPS upgrades (though your web server usually handles that). The Location header must be an absolute URL.

Common Causes

• Domain migration (old.com → new.com)
• URL path restructuring (/blog/post → /articles/post)
• Adding or removing www subdomain

HTTP Response Example

HTTP/1.1 301 Moved Permanently
Location: https://www.example.com/new-path
Cache-Control: max-age=31536000

Code Examples

// Redirect old URL to new URL permanently
app.get('/old-path', (req, res) => {
  res.redirect(301, '/new-path')
})

// Redirect HTTP to HTTPS (usually handled by nginx/Cloudflare)
app.use((req, res, next) => {
  if (!req.secure) return res.redirect(301, `https://${req.hostname}${req.url}`)
  next()
})

// next.config.ts
export default {
  redirects: async () => [
    {
      source: '/old-path',
      destination: '/new-path',
      permanent: true, // sets 308 (Next.js default for permanent)
    },
  ],
}

// Or in middleware.ts for dynamic redirects:
export function middleware(request: NextRequest) {
  return NextResponse.redirect(new URL('/new-path', request.url), 301)
}

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