Bitcoin, the most secure and decentralized blockchain, has become a cornerstone of trust in the crypto ecosystem. However, its design primarily supports peer-to-peer transactions, leaving its vast liquidity largely untapped for decentralized finance (DeFi). Developers and users often rely on centralized exchanges or multisig bridges to access Bitcoin liquidity, introducing trust issues and vulnerabilities. Meanwhile, Ethereum, the hub of DeFi innovation, lacks Bitcoin’s robust security model. This disconnect creates a fragmented ecosystem where Bitcoin’s unmatched security and Ethereum’s versatile applications operate in silos, hindering the development of secure and decentralized financial solutions.

As a Hybrid Layer 2 blockchain, BOB combines Bitcoin’s security with Ethereum’s innovation. It inherits security from Bitcoin’s Proof of Work while enabling developers to use Ethereum Virtual Machine (EVM) tools to build on Bitcoin seamlessly. By introducing trust-minimized systems powered by BitVM, BOB eliminates reliance on centralized exchanges and bridges. Moreover, it connects the liquidity of Bitcoin and Ethereum, creating a unified ecosystem for next-generation DeFi applications.

What is BOB?

Source: BOB website

BOB, short for Build on Bitcoin, is the first Hybrid Layer 2 (L2) blockchain that combines Bitcoin’s security with Ethereum’s DeFi functionality. It is designed to change how Bitcoin is used in decentralized finance by providing a secure and efficient platform for building decentralized applications (dApps). BOB inherits security from Bitcoin’s Proof of Work and offers compatibility with Ethereum Virtual Machine (EVM) tools, bridging the gap between two major blockchain ecosystems. Developers can use BOB’s Bitcoin developer suite, tooling, and dual liquidity to build fast and reliable solutions. As a Hybrid L2, BOB enables trust-minimized BTC deposits and withdrawals while connecting the liquidity of Bitcoin and Ethereum to support decentralized finance adoption.

The Mission and Vision of BOB

The mission of BOB is to make Bitcoin a cornerstone of decentralized finance by combining its security with scalable and user-friendly solutions. BOB aims to unlock Bitcoin’s full potential, enabling developers and users seamless access to decentralized financial tools.

BOB envisions a blockchain ecosystem in which Bitcoin’s security and decentralization drive the growth of DeFi. By fostering trust-minimized solutions, BOB envisions a future in which Bitcoin plays a central role in open, inclusive, and reliable financial systems.

The Technology Behind BOB

BOB is built on a robust technological stack that combines Bitcoin’s security and Ethereum’s development infrastructure.

Rollup Layer

The foundation of BOB’s technology lies in its Rollup Layer, designed to combine Bitcoin’s Proof-of-Work (PoW) security with Ethereum’s liquidity and flexibility. Initially built on the OP Stack, BOB supports seamless user and asset onboarding via Ethereum’s infrastructure. It incorporates cutting-edge developments like ZK improvements from RiscZero and uses merged mining protocols to connect to Bitcoin’s network. Although Bitcoin-native ZK rollups remain a long-term goal, BOB leverages BitVM for fraud-proof mechanisms and optimistic rollups to achieve secure, scalable transactions in the short term. This approach ensures that Bitcoin’s unmatched security is effectively utilized within a DeFi ecosystem.

EVM Core

At its core, BOB adopts the Ethereum Virtual Machine (EVM) to offer developers access to familiar tools and infrastructure, such as Hardhat, Metamask, and TheGraph. The EVM implementation on BOB mirrors Ethereum’s capabilities, enabling compatibility with Solidity-based smart contracts. This makes it easier for developers to build on Bitcoin without needing to learn a new programming paradigm. Additionally, BOB supports Bitcoin’s Rust zkVM, which facilitates off-chain execution of Bitcoin-based applications using zero-knowledge proofs. This ensures smooth integration between Bitcoin’s technical stack and Ethereum’s expansive developer ecosystem, paving the way for innovation on a unified platform.

Trustless Bitcoin Bridges

BOB offers trustless Bitcoin bridges that provide secure access to Bitcoin block and transaction data. These bridges enable peer-to-peer swaps, Ordinal auctions, and advanced tokenization models using tBTC v2 and other threshold-based systems. Through its ETH L1/L2 native bridge, BOB connects Ethereum’s market-leading assets with Bitcoin’s decentralized infrastructure. Future plans include introducing a two-way light-client BTC bridge powered by BitVM, making cross-chain transactions more secure and efficient. This functionality positions BOB as a critical player in bridging the two largest blockchain ecosystems.

BOB SDK

To simplify development on Bitcoin, BOB provides a powerful SDK that includes prebuilt Solidity contracts for interacting with Bitcoin features such as Ordinals, BRC20 tokens, and Lightning. It also enhances the user experience by supporting unified BTC and EVM wallets, enabling users to manage Bitcoin-based assets in familiar tools like MetaMask. With this SDK, developers can seamlessly integrate Bitcoin functionality into decentralized applications, advancing the broader adoption of Bitcoin as a foundational layer for DeFi.

BOB Gateway

BOB Gateway provides a seamless, one-click solution for using Bitcoin in decentralized finance. The Gateway eliminates complex interfaces and enhances the user experience by bridging Bitcoin and Ethereum. With BOB Gateway, users can swap BTC into tBTC, wBTC, and more assets on BOB through a unified interface. This innovation transforms Bitcoin’s role in DeFi, allowing instant integration into yield products, stablecoin swaps, and staking protocols. The Gateway represents a significant step forward in usability, unlocking Bitcoin’s potential as a versatile asset in DeFi while streamlining cross-chain interactions for users and developers alike.

How BOB Gateway Works

BOB Gateway’s heart is a trustless, RFQ-based cross-chain swap protocol connecting users with liquidity providers (LPs). This protocol ensures that neither users nor LPs need to trust each other, as swaps are secured by BOB’s Bitcoin light client. LPs handle bridging complexities, enabling smooth asset transitions while users only pay a fee for the service. Beyond swaps, the Gateway supports advanced DeFi integrations such as direct BTC staking into protocols like Solv and Pell. Future developments aim to enhance transaction speed, expand lending use cases, and introduce off-ramping capabilities. BOB Gateway is not just a bridge—it’s a foundation for Bitcoin’s active participation in decentralized ecosystems.

BOB Pay

BOB Pay is the revolutionary solution that makes sending Bitcoin and stablecoins as easy as sending an email. Gone are the days of managing complex wallets, apps, and seed phrases. With BOB Pay, sending and receiving crypto is simpler, faster, and more secure than ever before. Whether you’re sending Bitcoin or stablecoins, BOB Pay streamlines the process, opening the door for everyday users to enter the crypto world effortlessly.

How BOB Pay Works

BOB Pay’s interface is designed with simplicity in mind. To send crypto, users simply connect their Bitcoin wallet, enter the recipient’s email address and the amount, and click send. Transactions are completed in seconds, with fees as low as $0.01. The recipient can easily claim their funds by logging in with their email, making the process seamless for both senders and receivers.

Behind the scenes, BOB Pay uses cutting-edge technology, including wallet abstraction, smart accounts, and paymasters. Additionally, transaction fees can be paid in the currency being sent—whether it’s wBTC, USDT, or another asset. This flexibility enhances the user experience while maintaining the non-custodial nature of the transactions.

Why BOB Pay Matters

BOB Pay removes the barriers to entry that often deter new users from adopting Bitcoin. No more complicated wallet setups, seed phrase backups, or technical hurdles—just instant, low-cost transactions with an easy-to-understand interface. Users can export their keys afterward, ensuring full control over their assets.

Partnering with Dynamic, ZeroDev, and Pimlico, BOB Pay integrates seamless wallet management, smart accounts, and efficient paymasters, ensuring a top-notch experience.

BOB Fundraising Journey

Build on Bitcoin (BOB) has successfully secured $11.6 million in funding to fuel its development of a revolutionary hybrid Layer 2 protocol. This funding has come from a diverse group of investors, including prominent venture capital firms and industry leaders.

The most recent funding round, a strategic investment of $1.6 million, was led by Ledger, a renowned provider of hardware wallets.

Among the angel investors are leaders from major blockchain projects and financial institutions, including BlackRock, Rarible, Aave, Curve Finance, Magic Eden, and many more. Their support underscores BOB’s potential to unlock Bitcoin’s programmability while leveraging Ethereum’s innovative capabilities.

A significant portion of the raised funds, $1 million, will be allocated to a BOB incubator aimed at fostering new startups in the Bitcoin infrastructure and BOB dApp space. The goal is to bridge the gap between Bitcoin’s global adoption and Ethereum’s innovation, creating a seamless platform for dApp development.

BOB Roadmap

The BOB Hybrid L2 roadmap outlines the gradual phases of its development, aimed at combining the security of Bitcoin with the scalability and innovation of Ethereum’s DeFi ecosystem. Here’s an overview of the roadmap

Phase 1: Bootstrapping as an Ethereum L2

Launch Date: BOB first launched as an Ethereum L2 in May, using the OP stack. It includes a native Ethereum bridge and integrates third-party Bitcoin bridges.

Key Features:

• Supports Ethereum and Bitcoin assets.
• Enhances transaction speed and introduces fee token abstraction.
• Uses a BTC light client to track Bitcoin state in real time.

Phase 2: Bitcoin “Soft” Finality

Goal: BOB adds Bitcoin finality to its Ethereum L2 setup. This includes incorporating the Bitcoin finality protocol, where participants validate BOB chain states once per epoch.

Security Enhancements: It leverages BitVM for a trust-minimized Bitcoin bridge, securing the system against attacks by requiring corruption of most Bitcoin finality participants.

Improved Withdrawals: It will drastically reduce Ethereum bridge withdrawal delays from 7 days to a few minutes or hours.

Phase 3: Full Bitcoin Security

Key Goal: Integrate Bitcoin’s security model by using Bitcoin’s main chain for data availability.

Optimistic Rollups via BitVM: This step will require transitioning from Ethereum-based bridges to fully leverage Bitcoin’s security, making it the backbone of BOB’s infrastructure.

Challenges: The cost of data availability will be high, and the transition will occur once BOB reaches a scale where the additional fees won’t hurt transaction competitiveness.

Phase 4: ZK-Rollups (If Bitcoin Implements the Necessary Opcode)

Future Consideration: This phase will involve using ZK-rollups for scalability, but it depends on Bitcoin supporting necessary opcodes, which is a speculative aspect at the moment.

Key Vision and Future Goals:

• Bitcoin’s Role in DeFi: BOB aims to unlock Bitcoin’s full potential in DeFi by combining Bitcoin’s security with Ethereum’s developer tools and DeFi ecosystem.
• Hybrid Bridge: The Ethereum bridge will be secured by Bitcoin finality, making Ethereum’s DeFi more robust and secure.
• Trust-minimized Bitcoin bridging: This will enable trust-minimized BTC deposits and withdrawals using Bitcoin security.

Future Impact

Interoperability: BOB will enable trust-minimized, Bitcoin-secured bridges to other blockchains like Ethereum, Solana, and others, making Bitcoin the anchor of a decentralized and interoperable DeFi ecosystem.

Developer Opportunities:

The BOB Foundation will offer grants and support for developers building Bitcoin-based applications. Developers are encouraged to explore the BOB SDK to create solutions at the intersection of Bitcoin and Ethereum.

Conclusion

BOB’s phased approach—from bootstrapping as an Ethereum L2 to introducing Bitcoin finality and eventually inheriting Bitcoin’s complete security—ensures that the platform evolves, emphasizing scalability and user trust. As the platform grows, BOB aims to unlock Bitcoin’s full potential in DeFi, positioning it as the backbone of an interoperable, decentralized financial ecosystem. With an open invitation to developers and innovators, BOB is poised to reshape the landscape of blockchain finance, offering exciting possibilities for the future.