Singer's meta-ethical position

What is the point of view meta-ethics of Peter Singer? I don't have this clear.
He seems to accept the Hare's universal prescriptivism as background theory.
But what are the implications of accepting this theory?
specifically,
Singer would be:
cognitivist or non-cognitivist?
realist or anti-realist?
internalist or externalist?
Singer is a foundationalist?
What is the role of moral axioms in the construction of their theory?

Thank you,


P. S.: Sorry for the errors of English still starting.