Bitlayer is a Layer-2 solution on Bitcoin, utilizing the BitVM model to enable the execution of fully Turing-complete smart contracts while ensuring security on the Bitcoin network. The network operates on a rollup architecture, where states from L2 are continuously verified on L1 through the Recursive BitVM mechanism, ensuring the validity of the states through the cryptographic strength of Bitcoin. Bitlayer also integrates a Proof-of-Stake consensus mechanism to optimize performance, achieving soft finality times under 1 second and hard finality after about a week. The Bitlayer ecosystem also features the native token BTR for fee payments, staking, governance, and encouraging community development; the total supply is projected to be 1 billion tokens. This solution is viewed as a foundation to promote the robust development of the DeFi system on Bitcoin.