кроссплатформенный(Of, pertaining to, or characteristic of a software application or hardware device that can be run or operated on more than one system platform)
межплатформенный(e.g., that's a cross-platform application. The code is compiled on one platform and the resulting assembly is binary compatible with all other platforms); платформенно-независимый(англ. термин взят из кн.: Ottinger J.B., Minter D., Linwood J. Beginning Hibernate. – Apress, 2014. – 223 р. Alex_Odeychuk)