Error with Permissions-Policy header Unrecognized feature ‘attribution-reporting’

The error Error with Permissions-Policy header Unrecognized feature 'attribution-reporting' indicates that the browser encountered an unrecognized or unsupported feature in the Permissions-Policy HTTP header. This header allows web developers to control which features are enabled or disabled in their web app.

What is Attribution-Reporting?

The attribution-reporting feature is part of a newer API aimed at improving privacy while supporting ad click and conversion tracking without relying on third-party cookies.

Not all browsers currently support attribution-reporting, so when it is included in the Permissions-Policy header, unsupported browsers like Chrome (if the feature is not enabled) will throw this warning.

Why is React Involved?

It’s not. React itself doesn’t set the Permissions-Policy header. However, your server or a middleware (like in Express.js) might be adding it, or it could come from your hosting provider (e.g., Vercel, Netlify, or an HTTP proxy like NGINX).

How to Fix the Error

The error originates from the server configuration, not React itself. To fix the error, you can address the Permissions-Policy header.

---

Three Possible Fixes

Fix 1: Remove the attribution-reporting Directive

If your application does not rely on attribution-reporting, simply remove it from the Permissions-Policy header in your server or hosting configuration.

For Express.js:

Locate the part of your server code where headers are set:

   app.use((req, res, next) => {
       res.removeHeader("Permissions-Policy"); // Remove the header
       next();
   });

Or if you want to set it without attribution-reporting:

   app.use((req, res, next) => {
       res.setHeader("Permissions-Policy", "geolocation=(), microphone=()"); // Replace with supported features
       next();
   });

For NGINX: Edit your NGINX configuration to remove attribution-reporting:

   add_header Permissions-Policy "geolocation=(), microphone=()"; # Example supported features

Fix 2: Ensure Compatibility with Browser Support

If you intend to use attribution-reporting, ensure that it is supported by the browsers accessing your app. Add feature detection or conditional inclusion of the header.

For a Node.js server:

Check for browser support using req.headers['user-agent'] and conditionally add the header:

const userAgent = req.headers['user-agent'];
if (userAgent.includes('Chrome/')) {
  res.setHeader("Permissions-Policy", "attribution-reporting=()");
}

Fix 3: Update or Configure Dependencies

If the header is being added by a dependency (e.g., a library or hosting provider), update the dependency or override its configuration. If you’re using Vercel, you might want to use a vercel.json file:

{
    "headers": [
      {
        "source": "/(.*)",
      "headers": [
          {
            "key": "Permissions-Policy",
          "value": "geolocation=(), microphone=()"
        }
      ]
    }
  ]
}

---

Summary

The error is not caused by React but by a misconfigured Permissions-Policy header. You can resolve the issue by either removing the attribution-reporting directive, ensuring browser compatibility, or updating your dependencies or hosting configurations to handle the header correctly.