Ark is a Bitcoin Layer 2 protocol designed to scale transactions through a shared UTXO model, enabling fast, low-cost, and private off-chain payments. Utilizing virtual UTXOs (vTXOs) and Ark Service Providers (ASPs), Ark simplifies liquidity management by eliminating the need for payment channel setup, unlike the Lightning Network. Recent developments include Virtual Channels for off-chain contracts and Taproot Assets integration, enhancing BTCfi applications. Ark supports trustless, unilateral on-chain redemption, ensuring user control over funds.