Yes, INTERFACES is a Scrabble word!

Letter values in Scrabble US: I 1, N 1, T 1, E 1, R 1, F 4, A 1, C 3, E 1, S 1.

Is it a valid word?

INTERFACES is a valid word in the official Scrabble dictionary (US), the UK Scrabble Dictionary and Words with Friends (ENABLE).

(chemistry) a surface forming a common boundary between two things (two objects or liquids or chemical phases)
(computer science) a program that controls a display for the user (usually on a computer monitor) and that allows the user to interact with the system
the overlap where two theories or phenomena affect each other or have links with each other
(computer science) computer circuit consisting of the hardware and associated circuitry that links one device with another (especially a computer and a hard disk drive or other peripherals)

Also: user interface.