HTTP Redirects for SEO

Redirects tell browsers and search engines that a page has moved. The status code you choose affects whether search engines transfer ranking signals (PageRank) to the new URL.

"The 301 (Moved Permanently) status code indicates that the target resource has been assigned a new permanent URI and any future references to this resource ought to use one of the enclosed URIs."

Redirect Status Codes

HTTP defines several redirect status codes, each with different semantics and SEO implications. Understanding the difference between 301 and 302 is critical, as using the wrong code can prevent your new URL from inheriting the ranking power of the old one.

The table below summarizes the four main redirect codes you will encounter. Pay special attention to the SEO impact column, as this is where the real differences matter.

Now that you understand the codes, let's look at how to implement redirects across different platforms and frameworks.

Implementation

The implementation varies by platform, but the core concept is the same: respond with the appropriate status code and a Location header pointing to the new URL. Most frameworks provide convenient abstractions so you do not need to handle headers manually.

// Next.js (next.config.js)
module.exports = {
  async redirects() {
    return [
      {
        source: '/old-page',
        destination: '/new-page',
        permanent: true, // 301
      },
      {
        source: '/temporary-move',
        destination: '/temp-page',
        permanent: false, // 302
      },
    ];
  },
};

// Express.js
app.get('/old-page', (req, res) => {
  res.redirect(301, '/new-page');
});

// Nginx
location = /old-page {
  return 301 /new-page;
}

location = /temp-page {
  return 302 /maintenance;
}

Notice how each platform makes the distinction between permanent and temporary redirects clear. Next.js uses a boolean permanent property, Express uses the status code directly, and Nginx uses the return directive with the code.

One critical mistake to avoid is creating chains of redirects. This happens when you redirect A to B, then later redirect B to C, resulting in a chain.

Redirect Chains

Redirect chains occur when one redirect leads to another. This is surprisingly common on sites that have gone through multiple redesigns or CMS migrations without cleaning up old redirects. Each hop in the chain adds latency and historically diluted PageRank.

# BAD: Redirect chain
/page-v1 → 301 → /page-v2 → 301 → /page-v3 → 301 → /page-final

Problems:
- Slower page loads (multiple round trips)
- PageRank dilution (historically)
- Googlebot may stop following after ~5 hops

# GOOD: Direct redirect
/page-v1 → 301 → /page-final
/page-v2 → 301 → /page-final
/page-v3 → 301 → /page-final

The solution is to always redirect to the final destination. When you create a new redirect, check if the destination itself redirects somewhere else. If so, skip the middle step and point directly to the final URL.

With the technical details covered, let's summarize when to use each redirect type based on real-world scenarios.

When to Use Each Code

The following table maps common scenarios to the appropriate redirect code. When in doubt, ask yourself: is this change permanent? If yes, use 301. If the old URL might come back, use 302.

Note the 307 and 303 codes for form submissions. These preserve or change the HTTP method respectively, which matters when redirecting POST requests. Using 301 or 302 for POST requests can cause browsers to change the method to GET, potentially breaking form submissions.