Raspberry Pis are great for lots of things, but generally they're used for local stuff. A media player, a home-made tablet, robots, and all sorts of other stuff that requires you to be there using it. The PiTunnel app lets you access your Pi remotely, without compromising on security.
According to PiTunnel's website it only takes a single command to setup remote access, and once you select the network service you want to access (like SSH, VNC, HTTP, FTP, and so on) you'll be able to access your Pi Projects via the PiTunnel website or a remote terminal.
This idea isn't unique but PiTunnel's creator, programmer Dimitri Raftopoulos, has made his own stand out. According to Raftopoulos most remote access apps focus on remote terminal access, but PiTunnel is all about tunnelling. Essentially that means you can access any network service running on your mini computer without having to do a lot of complicated work to set it up. No router configuration, static IP addresses, or VPNs to worry about.
PinTunnel's goal is pretty in line with the Raspberry Pi mission, in that Raftopoulos wants people to be able to use the app to run whatever they want - whether it's strictly for personal use or if it's accessible by others. PiTunnel has HTTPS security, a built-in live device monitor to see how your computer is doing, custom tunnels, HTTP subdomain access, and TLS tunnel encryption.
The downside is that it isn't free. Not if you want to do anything serious with it anyway. The free option restricts you to one device, one custom tunnel, and 100 MB/day transfer limit. The standard $5/£3.74 a month option lets you use two devices, four custom tunnels, a 200MB/day transfer limit, and lets you name your tunnels. The top-tier plan is $15/£11.22 a month, and lets you use 10 devices, 50 custom tunnels, has a 500MB/day transfer limit, priority bandwidth, and named tunnels.