Textwell supports several URL schemes which allow other apps to call methods of Textwell remotely and to make Textwell callback other apps to pass some data. See the reference for more information.
Because Textwell is just a text box actually, its high customizability is the premise of convenience. Textwell has some pre-installed useful actions, but they are no more than examples. Adding new actions or modifying the existing actions to make them fit different user contexts is truly expected in the design concept of Textwell. See the reference for more information.