Attribution
TactiKing is built on open data and open-source software.
Puzzles
The tactical positions come from the public Lichess puzzle database, released under the Creative Commons CC0 licence. Lichess does not endorse TactiKing.
Engine
Position analysis uses Stockfish, distributed under the GNU General Public License v3.
Other software
TactiKing also uses open-source libraries such as chess.js and react-chessboard, under their respective licences.