The "osu! Tourney Match Displayer" app shows in real-time the stats of an ongoing osu! multiplayer match. It's meant to be used with tournament matches.

The app get's only your public informations and get all the data of the match you are playing. No sensitive data will be managed by the app.
Remember that you must not show your api key to anyone, if this happens generate a new api key from the osu! website.

The app works with most of tournaments but there are some tournaments that have custom rules/mods multipliers, so the supported tournaments are tournaments that are completely supported from the app with the custom rules.
The app will recognize automatically the tournament from the lobby name.

You can get your osu! API key here: osu.ppy.sh/p/api.
This link gets you on the old osu! website because the API key page is not present on the newer website. Once you login on the oldest website you'll be redirected to the newer one, this will be a little tricky but continue to go back and reload again and again the api key link and after a while you'll get the right page!