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vercel.json file

The vercel.json file is Vercel’s configuration file that allows you to customize how your project is built and deployed. It sits in your project’s root directory and controls various aspects of your deployment, including routing, redirects, headers, and build settings. We use the rewrites configuration to proxy requests from your main domain to your documentation. Rewrites allow you to map incoming requests to different destinations without changing the URL in the browser. When someone visits yoursite.com/docs, Vercel will internally fetch content from your-subdomain.mintlify.dev/docs but the user will still see yoursite.com/docs in their browser. This is different from redirects, which would send users to a different URL entirely.

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Configuration

To host your documentation at a custom /docs subpath using Vercel, add the following configuration to your vercel.json file: 
{
  "rewrites": [
    {
      "source": "/docs",
      "destination": "https://[subdomain].mintlify.dev/docs"
    },
    {
      "source": "/docs/:match*",
      "destination": "https://[subdomain].mintlify.dev/docs/:match*"
    }
  ]
}
  • source: The path pattern on your domain that triggers the rewrite.
  • destination: Where the request should be proxied to.
  • :match*: A wildcard that captures any path segments after /docs/.
For more information, see Configuring projects with vercel.json: Rewrites in the Vercel documentation.

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Using external proxies with Vercel

If you’re using an external proxy (like Cloudflare or AWS CloudFront) in front of your Vercel deployment, you must configure it properly to avoid conflicts with Vercel’s domain verification and SSL certificate provisioning. Improper proxy configuration can prevent Vercel from provisioning Let’s Encrypt SSL certificates and cause domain verification failures. See the supported providers in the Vercel documentation.

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Required path allowlist

Your external proxy must allow traffic to these specific paths without blocking, redirecting, or heavily caching:
  • /.well-known/acme-challenge/* - Required for Let’s Encrypt certificate verification
  • /.well-known/vercel/* - Required for Vercel domain verification
  • /mintlify-assets/_next/static/* - Required for static assets
These paths should pass through directly to your Vercel deployment without modification.

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Header forwarding requirements

Ensure that your proxy correctly forwards the HOST header. Without proper header forwarding, verification requests will fail.

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Testing your proxy setup

To verify your proxy is correctly configured:
  1. Test that https://[yourdomain].com/.well-known/vercel/ returns a response.
  2. Ensure SSL certificates are provisioning correctly in your Vercel dashboard.
  3. Check that domain verification completes successfully.