.htaccess

# ----------------------------------------------------------------------
# SERVE PRE-COMPRESSED STATIC FILES
# ----------------------------------------------------------------------
# This block enables serving pre-compressed .gz and .br files if they
# exist and the client supports them. Brotli is preferred over Gzip.

<IfModule mod_rewrite.c>
  RewriteEngine On

  # Rule to serve Brotli (.br)
  # 1. Check if the browser sent the "Accept-Encoding: br" header.
  RewriteCond %{HTTP:Accept-Encoding} br
  # 2. Check if a .br version of the requested file exists on the server.
  RewriteCond %{REQUEST_FILENAME}.br -f
  # 3. If both are true, rewrite the request to serve the .br file.
  RewriteRule ^(.*)$ $1.br [L]

  # Rule to serve Gzip (.gz) as a fallback
  # 1. Check if the browser sent the "Accept-Encoding: gzip" header.
  RewriteCond %{HTTP:Accept-Encoding} gzip
  # 2. Check if a .gz version of the requested file exists on the server.
  RewriteCond %{REQUEST_FILENAME}.gz -f
  # 3. If both are true, rewrite the request to serve the .gz file.
  RewriteRule ^(.*)$ $1.gz [L]
</IfModule>

<IfModule mod_headers.c>
  # For the rules above to work, we must set the correct content encoding
  # and content type headers for the compressed files.

  # Serve .br files with the Brotli content encoding
  <FilesMatch "\.br$">
    Header set Content-Encoding br
  </FilesMatch>

  # Serve .gz files with the Gzip content encoding
  <FilesMatch "\.gz$">
    Header set Content-Encoding gzip
  </FilesMatch>

  # Set content type for the compressed binary file
  <FilesMatch "\.bin\.(gz|br)$">
    Header set Content-Type application/octet-stream
  </FilesMatch>

  # IMPORTANT: Add the Vary header to deal with caches/proxies.
  # This tells caches that the response can be different based on the
  # Accept-Encoding header, preventing them from serving a cached
  # compressed version to a browser that doesn't support it.
  <FilesMatch "\.(js|css|xml|gz|br|bin)$">
    Header append Vary Accept-Encoding
  </FilesMatch>
</IfModule>