Nginx reverse proxy with caching for Next.js with imgproxy

nginx.conf

# Based on https://steveholgado.com/nginx-for-nextjs/

# - /var/cache/nginx sets a directory to store the cached assets
# - levels=1:2 sets up a two‑level directory hierarchy as file access speed can be reduced when too many files are in a single directory
# - keys_zone=STATIC:10m defines a shared memory zone for cache keys named “STATIC” and with a size limit of 10MB (which should be more than enough unless you have thousands of files)
# - inactive=7d is the time that items will remain cached without being accessed (7 days), after which they will be removed
# - use_temp_path=off tells NGINX to write files directly to the cache directory and avoid unnecessary copying of data to a temporary storage area first
proxy_cache_path /var/cache/nginx levels=1:2 keys_zone=STATIC:10m inactive=7d use_temp_path=off;

upstream nextjs_upstream {
  server localhost:3000;
}

upstream imgproxy_upstream {
  server localhost:8080;
}

server {
  listen 80 default_server;

  server_name _;

  server_tokens off;

  gzip on;
  gzip_proxied any;
  gzip_comp_level 4;
  gzip_types text/css application/javascript image/svg+xml;

  proxy_http_version 1.1;
  proxy_set_header Upgrade $http_upgrade;
  proxy_set_header Connection 'upgrade';
  proxy_set_header Host $host;
  proxy_cache_bypass $http_upgrade;

  # Imgproxy paths can contain multiple slashes (e.g. local:///image/file.jpg)
  merge_slashes off;

  location /img/ {

    proxy_cache STATIC;

    proxy_pass http://imgproxy_upstream/;

    # For testing cache - remove before deploying to production
    add_header X-Cache-Status $upstream_cache_status;
  }

  location /_next/static {
    proxy_cache STATIC;
    proxy_pass http://nextjs_upstream;

    # For testing cache - remove before deploying to production
    add_header X-Cache-Status $upstream_cache_status;
  }

  location /static {
    proxy_cache STATIC;

    # Ignore cache control for Next.js assets from /static, re-validate after 60m
    proxy_ignore_headers Cache-Control;
    proxy_cache_valid 60m;

    proxy_pass http://nextjs_upstream;

    # For testing cache - remove before deploying to production
    add_header X-Cache-Status $upstream_cache_status;
  }

  location / {
    proxy_pass http://nextjs_upstream;
  }
}