BOB (“Build on Bitcoin”), a hybrid layer 2 (L2) powered by Bitcoin and Ethereum, has successfully tested a prototype for its first BitVM-powered, trust-minimized Bitcoin bridge, in partnership with Fiamma, a leading BitVM developer and zero-knowledge infrastructure company.
BOB will be among the first Layer 2 solutions to both inherit Bitcoin’s security and develop a prototype BitVM-based bridge. BitVM is a revolutionary system that enables programs to be executed on Bitcoin optimistically, without requiring any forks or protocol changes, unlocking new levels of utility and scalability for BTC.
Existing bridges typically rely on centralized entities—such as Wrapped Bitcoin (wBTC) and Coinbase Wrapped Bitcoin (cbBTC)—or semi-trusted networks like tBTC, where security depends on the honesty of the majority of participants. In contrast, BitVM bridges introduce a superior security model: BTC deposits and withdrawals remain secure as long as at least one party acts honestly. Anyone can raise a challenge to ensure funds remain safe. BOB’s co-founder Alexei Zamyatin is a core research contributor and co-author of the BitVM2 technical paper, providing the BOB team with unparalleled insight into the potential of this approach.
Alexei Zamyatin, BOB Co-Founder and core BitVM research contributor said: “Bitcoin security and trust-minimized BTC bridging is what sets Bitcoin L2s apart from all other chains. Security from the most robust and decentralised network, paired with a way to deposit and withdraw BTC without trusting any third party. So far, this has not been possible, almost all BTC bridges are trusted multisigs. Only now, for the first time in Bitcoin’s history, do we finally have a blueprint and a prototype for achieving this in practice with BitVM2.”
“Bitcoin security and trust-minimized BTC bridging are the two most important pillars of Bitcoin L2s. Previously treated as the unreachable holy grail, this can now be achieved via Bitcoin staking and BitVM2.”
To accelerate its implementation of BitVM2, BOB teamed up with Fiamma, the pioneer behind the first products utilizing BitVM2, including the first BitVM bridge and the first BitVM-powered verification layer on Bitcoin. Together they have deployed key bridge infrastructure and trialled an early version of the prover software to verify BOB’s consensus. Following this prototype’s public delivery, BOB plans to roll out the BitVM bridge on the BOB testnet in early 2025, with the mainnet deployment to follow after successful audit and partner integration.
Cyimon Chen, Fiamma Co-founder and core BitVM contributor said: “We’re excited to announce our partnership with the BOB team! We deeply appreciate Alexei and his team’s valuable insights during our discussions. We look forward to integrating the BitVM Bridge into BOB, making it the first Bitcoin Layer 2 with a trust-minimized bridge. We hope BOB’s BitVM bridge prototype is the first of many impressive announcements that result from our strategic partnership.”
Upon public release, the bridge will allow BOB users to deposit and withdraw BTC without relying on a third party. They will be able to lock BTC on Bitcoin and mint a fully fungible ERC20 bridged BTC on BOB, and then redeem BTC back to Bitcoin at any time. In the ideal case, the bridging process will take less than one hour each way, which is much faster than existing Ethereum L1 or L2 bridges to Bitcoin.
Earlier this week, BOB announced its planned integration with Babylon, the leading BTC staking protocol, which will establish BOB as a Bitcoin-secured network and provide Bitcoin finality to its blockchain. Trust-minimized bridging and Bitcoin finality are essential components of BOB’s hybrid design, which aims to combine Bitcoin’s security and liquidity with Ethereum’s DeFi innovation and versatility, establishing BOB as the home for BTC DeFi. The successful bridge prototype test starts the rollout of phase 2 of BOB’s roadmap, as it becomes an Ethereum L2 with Bitcoin finality, leveraging enhanced security, a trust-minimized BitVM BTC bridge, and faster withdrawals on the native ETH bridge.
BOB supports a thriving ecosystem with $200+ million in DeFi Total Value Locked (TVL), featuring BTC LSTs by Lombard, Solv, Bedrock, and PumpBTC. In addition, BOB’s 1-click staking product, BOB Stake, will make it easy for millions of users to stake BTC in DeFi with just a single Bitcoin transaction, through integrations with third-party staking services like Staking Rewards, Pell, Xverse Earn and Everstake.