scores.fiba3x3.com is an Internet-cloud based web application that connects what is happening on the event venue scoring systems to the global FIBA 3x3 database, enabling automatic feeding of results to the schedules and, for example, live scoring widgets.
Hence, if you plan to use it, you should make sure you have good Internet connection in place.
Scores.fiba3x3.com has been designed to work offline, but for every competition, it needs internet connection to download the competition information (game list) before each stage of the competition. With the initial download, the app downloads the information for the first set of games, such as Pool games, and throughout the advancement of the competition - such as moving from Pool phase to Quarterfinals, or from Quarterfinals to Semifinals - the app needs to download progression information (e.g. who are the teams of the semi-finals)
Now, if the competition information has been downloaded at least once, the Custom Game mode will work despite missing progressions.
Do note that any Internet connection will work for getting the game data. So, for example, if the official venue Internet is down, one can, for example, use any mobile phone to share the hotspot and use that as the connection to launch the app and get the game directory information. Once that is downloaded, the scores app will work in offline mode.
This means that the web app continues to work normally, even if the Internet connectivity goes off for some time during the game. In that situation, the app stores all the game actions to the computer's local database and sends them to the Cloud when the connections is restored. Naturally, the live scoring widget is not updated when the Internet connectivity is not working.