EM Field Visualizer is an interactive 3D web app for exploring electric and magnetic fields in real time. Built with React and Three.js, it lets you place, move, and remove charges while instantly seeing how the fields change around them. You can visualize electric field lines and vectors, magnetic fields around current-carrying wires, and common charge setups like dipoles and quadrupoles. A test charge shows force direction, and controls allow you to adjust field strength and animation speed. On mobile, gyroscope support lets you rotate the scene by tilting your phone..