Solid Explorer is a relatively newer file manager app for Android. It is in the direct competition with ES File Explorer which is another very fine file manager app for the Android devices. One of the features that Solid Explorer offers is a built in FTP server using which you can access the files located on your Android smartphone over the WiFi network through the FTP protocol. This is better than accessing your files using a USB data cable because of many reasons – the WiFi transfer speed is uniform and faster, the WiFi FTP can be accessed from any computer connected to the same WiFi network, and the WiFi FTP method works even when you misplace your trustworthy USB data cable.
In order to use the Solid Explorer FTP server, you have to first install an extension called Solid Explorer FTP server from the Play store. Obviously, you should already have installed Solid Explorer in your Android phone before install the FTP server extension.
After this extension has been installed, you can launch Solid Explorer and tap on the hamburger menu icon and select FTP server from this menu. It will show some of the basic information about your WiFi network and the server status. The server status includes the IP address along with the port number for the FTP server. You can tap on the Start button to start the server. You can use the displayed the IP address and the port number to access the files from any other device connected to the same WiFi network.
You can pull down the ellipses menu to change various options related to the FTP server like the username, password, base folder, the port, anonymous access or to create a shortcut to the FTP server on the Android home screen.
Conclusion: Solid Explorer can be extended to be used as a WiFi FTP server so that you can access your Android files from any other device easily. If you have a rooted device, this server also lets you access the system partitions of your Android device over the FTP server.
You can download Solid Explorer FTP Server from https://play.google.com/store/apps/details?id=pl.solidexplorer.plugins.ftpserver&hl=en.