BCDEx is a cross-chain exchange network that uses the HTLC script of Bitcoin and Lightning Network to build a C2C trading protocol using smart contracts. This enables users to complete asset exchanges in a decentralised and non-custodial environment, such as BTC and ETH. BCDEx not only supports fully decentralised on-chain exchanges, but also provides payment channels for cross-chain paths and automatic exchanges. The traded content includes homogeneous tokens (FT), non-homogeneous tokens (NFT), and Inscription assets issued by the Ordinals protocol, thus enabling multi-chain asset interoperability and value conversion.