On December 8, 2021, Ethereum scale-up solution xDai announced that the proposal to merge with Gnosis has been approved, and the replacement of STAKE tokens with GNO tokens will officially begin, and xDai Chain will change its name to Gnosis Chain. Like Ethereum, xDai is also a chain, because xDai is derived from ethereum chain, xDai is mainly used to share the overflow transactions on Ethereum, has the nature of subordination, so many people call xDai as the sister chain, side chain of Ethereum. The idea of xDai was proposed by POA Network founder Igor Barinov during an Ethereum hackathon in 2018. At the time, the crypto community was trying to figure out a crypto bank for payments that could not be as volatile as BTC or as expensive as USDT, which operates on the Ethereum and Bitcoin networks. So Igor Barinov came up with the idea of connecting the Secure coin bridge to the side chain. Therefore, in the same year, POA Network and MakerDAO jointly released Safe Coin blockchain xDai. XDai mainly has four characteristics: Safe coin blockchain, fast/cheap, compatible with Ethereum, and many old project support. First, xDai's original intention is to connect the Safe coin bridge to another chain to reduce the cost of buying and selling online. Secure coin xDai on xDai is generated according to Dai on Ethereum. Transactions and payments on xDai chain are made using xDai. So just as Flow focuses on NFT, xDai is a blockchain based on Dai, an ecosystem based on Safe Coin. Secondly, xDai uses a consensus mechanism similar to PoS (PoSDAO), so the speed on the chain is relatively fast, the transaction cost is low and stable. The cost of a transaction on Ethereum can vary widely due to fluctuating ETH prices and network congestion, with a simple transaction costing anywhere from a few dollars to several hundred dollars. On xDai, 500 trades cost about $0.10. Third, xDai is compatible with Ethereum. The advantages of chain and chain compatibility are now well demonstrated in the process of ecological (DApp and composability between projects) relocation. Polygon's success and Arbitrum's false start all benefit from their compatibility with Ethereum to a certain extent. The xDai network follows the same protocol updates, block size limits, and virtual machine parameters as Ethereum, making it relatively easy for developers and users to move between xDai and Ethereum across the chain in both directions. It is also benefited from this point, now xDai ecology has been relatively rich. Fourth, xDai is supported by a number of established projects, including MakerDAO, Gnosis, Chainlink, Sushi, Curve, Circles, Metamask, etc. The reason for this reverse, on the one hand, may be because the multi-layer 2 layout itself is the right choice for the project side, which can reduce the risk and make it easier to bet on the future of the head of the Layer2 ecosystem. On the other hand, the team on the back of xDai may be a big draw for other project parties to deploy on xDai. Igor Barinov is a technology giant with a lot of recognition. Aside from Igor, most of the xDai center team members are veteran blockchain developers, and xDai is consistently among the top 10 liveliest teams on GitHub.