xDai Chain is a US dollar stable currency blockchain jointly launched by the MakerDAO Foundation and POA Network. It is also a side chain compatible with Ethereum. It uses the stable currency xDai (decentralized stable currency on Ethereum) Dai is exchanged on the side chain at a ratio of 1:1) as the basic token for transactions and payment of gas fees, and through STAKE tokens, with the help of a unique proof-of-stake algorithm—POSDAO for bookkeeping and governance.

The single token used by xDai Chain is used for transactions and payment of gas, which eliminates the need to hold additional ETH to pay gas on the Ethereum mainnet, and can realize low-cost fast payment with stable handling fees. It is suitable for building application scenarios based on payment and DeFi. In the future, this sidechain model will be further extended to other stablecoins other than Dai and other main chains other than Ethereum, and STAKE will still exist as the governance token of these sidechains.