Introduction : What is Polygon Fx-Portal? ✍️The Fx-Portal is Polygon’s permission-less, highly flexible meta-bridge built on top of the State Sync and Checkpointing mechanisms to facilitate the movement of data and asset across ethereum and Polygon. The key tunneling smart contracts: ✍️The Fx-Portal works through 4 important smart contracts - FxRoot, FxChild, FxBaseRootTunnel and FxBaseChildTunnel.