nginx.conf

server {
    listen ${NGINX_PORT};
    server_name  ${NGINX_SERVER_NAME};

    root   /usr/share/nginx/html;
    index  index.html index.htm;
    include /etc/nginx/mime.types;

    gzip on;
    gzip_min_length 1000;
    gzip_proxied expired no-cache no-store private auth;
    gzip_types
                text/css
                text/plain
                text/javascript
                application/javascript
                application/json
                application/x-javascript
                application/xml
                application/xml+rss
                application/xhtml+xml
                application/x-font-ttf
                application/x-font-opentype
                application/vnd.ms-fontobject
                image/svg+xml
                image/x-icon
                application/rss+xml
                application/atom_xml;

    location /de/ {
        alias   /usr/share/nginx/html/de/;
        try_files $uri$args $uri$args/ /de/index.html;
    }
    location /en/ {
        alias   /usr/share/nginx/html/en/;
        try_files $uri$args $uri$args/ /en/index.html;
    }

    set $first_language $http_accept_language;
    if ($http_accept_language ~* '^(.+?),') {
        set $first_language $1;
    }

    set $language_suffix 'de';
    if ($first_language ~* 'de') {
        set $language_suffix 'de';
    }
    if ($first_language ~* 'en') {
        set $language_suffix 'en';
    }

    location / {
        rewrite ^/$ http://${NGINX_SERVER_NAME}/$language_suffix/index.html permanent;
    }

    location ~* .(js|css|ttf|ttc|otf|eot|woff|woff2)$ {
        add_header access-control-allow-origin "*";
        expires max;
    }
}