Ive seen some apps where you can open your computers web-browser, type in the local IP address to the android device, and access a homepage that hosts from the device.

An example is this app: [Finger Timer - play.google.com](https://play.google.com/store/apps/details?id=tw.url.omega.fingertimerfree&feature=search_result#?t=W251bGwsMSwxLDEsInR3LnVybC5vbWVnYS5maW5nZXJ0aW1lcmZyZWUiXQ)

Does anyone know how this is done? Does Google have an API for this, or do you have any examples that I can start with? Im not a professional developer, so I prefer to keep it simple (few technologies). 

What I had in mind was something like this:

* Create a HTML or PHP page on my device
* Feed it with some information from my app somehow
* Host that page, so it can be accessed from any web-browser on any device on a local network.