TMT2 App (software) sVMS2000 ,Can view upto 16 devices.  You do not need to have a VPN it can be accessed from anywhere as long as the ip address is reachable.  The  sVMS software has DDNS capability (what is DDNS, you can get a free account with a Dynamic DNS service that lets you use a domain name to access your home network, you can then access your device by a name instead of remembering the ip address), also would have to configure any firewall to allow the traffic through to your device behind it.