Options
X-DNS-Prefetch-Control
This header controls DNS prefetching, allowing browsers to proactively perform domain name resolution on external links, images, CSS, JavaScript, and more. This prefetching is performed in the background, so the DNS is more likely to be resolved by the time the referenced items are needed. This reduces latency when the user clicks a link.
 {
  key: 'X-DNS-Prefetch-Control',
  value: 'on'
}
Strict-Transport-Security
This header informs browsers it should only be accessed using HTTPS, instead of using HTTP. Using the configuration below, all present and future subdomains will use HTTPS for a max-age of 2 years. This blocks access to pages or subdomains that can only be served over HTTP.
If you're deploying to Vercel, this header is not necessary as it's automatically added to all deployments unless you declare headers in your next.config.js.
 {