His works represent the Sturm und Drang style, virtuosity and briliance.  His music resembles of C.P.E. Bach who exiested in the same period of composition.  His compositions were born of improvisation. He state in his letter that with him often “only an outline exists”, and awaits to be developed.  He was the first to use the term fortepiano in a published work, in the title of his Duetto für 2 Clavier, 2 Flügel, oder 2 Fortepiano (1771)

‘I have devised many a piece when in good humour and a cheerful mood, but only in outline, and the pieces await a happy disposition of my mind for further work to be done, for I do not care to work when I am not disposed to it. And that true cheerfulness of mind I require to work visits me only rarely’. - The extract from a letter by Müthel