I am using Stockfish ( https://stockfishchess.org/ ) chess engine in the backend to analyze games and create puzzles.
I am using Chess.com and Lichess public APIs to allow users to fetch their own games.
I have used this icon https://www.flaticon.com/free-icon/strategy_1322264?term=chess%20piece&related_id=1322264 to create a loader icon in the app.

In this application, you can fetch your own or somebody else's games from Chess.com and Lichess public APIs and filter them using various options like openings, the colour of the piece, the result of the game and then select the games you want to be analysed by Stockfish in the backend.
After the games are analysed on the backend you can then start improving your tactical skills on the situations from your games and not games of some grandmaster so that you can actually get familiar with positions that you face yourself.