This solver can solve all Sudoku puzzles. It can determine if a puzzle is unique or have multiple solutions. There is a counter showing the number of solutions available for a puzzle.
Besides the standard Sudoku, this solver can also handle X-Sudoku and Hyper-Sudoku.
For this free version, some features are not enabled. To have all features, buy the premium version: https://play.google.com/store/apps/details?id=com.zhink.sudokudance