osTicket does not officially support nginx (why the *** not?) and a official maintainer seems to be missing at github -> 998 open issues, 196 pull requests. Open Source is a hard work these days - People request things you would never think of and people are not really independent. Asking the easiest questions you could think of instead of using google.

Despite that OsTicket is a really easy to use ticket system - And everything else would be overkill - Or do you know another small ticket system?

B2T - I migrated OsTicket (v1.10) from Apache to nginx (1.10.0), but I ran into some problems with the nginx configuration respectively the fastcgi params. So here is my working nginx configuration

server {
...

    set $path_info "";

    location ~ /include {
        deny all;
        return 403;
    }

    if ($request_uri ~ "^/api(/[^\?]+)") {
        set $path_info $1;
    }

    location ~ ^/api/(?:tickets|tasks).*$ {
        try_files $uri $uri/ /api/http.php?$query_string;
    }

    if ($request_uri ~ "^/scp/.*\.php(/[^\?]+)") {
        set $path_info $1;
    }

    location ~ ^/scp/ajax.php/.*$ {
        try_files $uri $uri/ /scp/ajax.php?$query_string;
    }

    location ~ ^/ajax.php/.*$ {
        try_files $uri $uri/ /ajax.php?$query_string;
    }

    location ~ ^/kb/ajax.php/.*$ {
        try_files $uri $uri/ /kb/ajax.php?$query_string;
    }

    location / {
        try_files $uri $uri/ index.php;
    }

    location ~ \.php$ {
        fastcgi_param  SCRIPT_FILENAME  $document_root$fastcgi_script_name;
        include fastcgi_params_ost;
        fastcgi_pass unix:/run/php/php7.0-fpm.sock;
        fastcgi_param  PATH_INFO        $path_info;
    }

}

_/etc/nginx/fastcgi_paramsost

fastcgi_param   QUERY_STRING            $query_string;
fastcgi_param   REQUEST_METHOD          $request_method;
fastcgi_param   CONTENT_TYPE            $content_type;
fastcgi_param   CONTENT_LENGTH          $content_length;

fastcgi_param   SCRIPT_FILENAME         $request_filename;
fastcgi_param   SCRIPT_NAME             $fastcgi_script_name;
fastcgi_param   REQUEST_URI             $request_uri;
fastcgi_param   DOCUMENT_URI            $document_uri;
fastcgi_param   DOCUMENT_ROOT           $document_root;
fastcgi_param   SERVER_PROTOCOL         $server_protocol;

fastcgi_param   GATEWAY_INTERFACE       CGI/1.1;
fastcgi_param   SERVER_SOFTWARE         nginx/$nginx_version;

fastcgi_param   REMOTE_ADDR             $remote_addr;
fastcgi_param   REMOTE_PORT             $remote_port;
fastcgi_param   SERVER_ADDR             $server_addr;
fastcgi_param   SERVER_PORT             $server_port;
fastcgi_param   SERVER_NAME             $server_name;

fastcgi_param   HTTPS                   $https if_not_empty;

# PHP only, required if PHP was built with --enable-force-cgi-redirect
fastcgi_param   REDIRECT_STATUS         200;