Build on Bitcoin (BOB), a rapidly growing Bitcoin Layer 2 protocol, is making waves in the space. Their current campaign, #BOBFusion Season 1, which started on March 27, has already attracted:

• 3,600+ participants

• $120M+ in Total Value Locked (TVL)

Curious to learn more about this protocol?

In this article, I'll cover the essentials of BOB and how you can get involved.

What is Build on Bitcoin (BOB)?

BOB (Build on Bitcoin) is a new Bitcoin L2 stack that combines Bitcoin's security and adoption with Ethereum's programmability and scalability.

It enhances Bitcoin's functionality by supporting existing Bitcoin tech (Ordinals, Lightning, Nostr), EVM smart contracts, and Ethereum rollups, while using Bitcoin L1 for settlement, custody, and storage.

Use cases

There are several potential use cases and ideas for building on top of Bitcoin such as:

• Decentralized Bitcoin interest - Converting staking rewards from other tokens into Bitcoin

• Zap money - Enabling fast, micro Bitcoin transfers

• Account abstraction for BTC wallets

• BRC20 - Bridging assets to Bitcoin as BRC20 tokens (BRC21 standard)

• Bridging BRC20 tokens from Bitcoin to other ecosystems (BRC42 standard)

• AI & Bitcoin integrations

Tech Stack

The BOB tech stack supports the existing Bitcoin tech stack, incl. Ordinals, Lightning and Nostr and can be applied on different verticals such as DeFi, wallets and gaming.

Let’s deep dive on the different components of the BOB tech stack:

Rollup Layer

• Bitcoin PoW security, native Ethereum bridge

• Launches on OP stack (incl. zkVM improvements by RiscZero), can be rolled up to Ethereum

• Can inherit Bitcoin security via a novel merged mining protocol (re-staking for Bitcoin).

• Goal: settle directly on Bitcoin L1 via optimistic rollup with BitVM

EVM Core

• Smart contracts, Solidity programming language

• Compatible with existing developer tooling, wallets, and infrastructure

Rust zkVM

• Supports Bitcoin's Rust libraries via RISC Zero zkVM

• Future avenue for ZK rollups directly on Bitcoin

Bitcoin Bridges

• Trustless access to BTC data via light client

• Supports decentralized and institutional bridges (wBTC, tBTC v2)

• Goal: 2-way light-client BTC bridge powered by BitVM

BOB SDK

• Universal toolkit for building on Bitcoin

• Solidity contracts for interacting with Bitcoin components

• Improved inscription APIs and tools for unified BTC/EVM wallet experience

• Account Abstraction with bridged BTC

Roadmap

The BOB (Build on Bitcoin) L2 rollup will launch in multiple phases to gradually improve its security.

Phase 1 - Optimistic BOB

BOB will launch as an optimistic ETH rollup using the OP stack, with settlement on Ethereum L1.

It will track Bitcoin state via a light client and import Bitcoin assets through trust-minimized and trusted bridges.

OP Stack was chosen because it aligns with BOB's values of experimentation, real-world impact, and freedom of choice.

It allows developers to quickly deploy new protocols without reimplementing existing ones in new languages.

BOB benefits from the OP’s stack infrastructure, marketing, and business development support.

This BOB OP-Stack deployment can eventually be made Superchain-compatible, allowing users to move seamlessly between different Superchain rollups.

Phase 2 - Bitcoin PoW Security + ETH Optimistic Rollup

BOB will introduce Bitcoin PoW security to the ETH rollup using a new merged mining technique, minimizing trust in sequencers.

Phase 3 - Bitcoin Optimistic Rollup + ETH ZK/Optimistic Rollup

Aiming to introduce Bitcoin as the settlement layer for BOB using BitVM to encode fraud proofs in Bitcoin script without requiring forks.

This will allow a set of operators to act as sequencers, ensuring rollup security as long as at least one operator is honest and online.

The transition to an optimistic rollup settling on Bitcoin will involve designing a BOB light client in BitVM, creating a 2-way bridge between Bitcoin and BOB using bi-directional light clients, and finally expanding the BitVM program to fully validate the BOB rollup state and accept fraud proofs.

BOB’s Ecosystem

The BOB ecosystem currently has around 50 projects, including DeFi dAPPS, infrastructure, and wallets.

Recently, BOB has announced it’s partnership with Velodrome, which blends the MetaDEX capabilities of Velodrome in BOB.

Investors

𝐁𝐎𝐁 𝐡𝐚𝐬 𝐬𝐞𝐜𝐮𝐫𝐞𝐝 𝐚 $𝟏𝟎𝐌 𝐬𝐞𝐞𝐝 𝐫𝐨𝐮𝐧𝐝 led by Castle Island Ventures, alongside other leading investors.

On-chain Metrics

It’s current campaign #BOBFusion Season 1 has (started on 27 March) and has:

• 3.6k+ participants

• $120M+ TVL locked

TVL highlights (as of 4 April 2024):

• $46M in $BTC assets

• $19.8M in $ETH assets

• $8.8M in stables

• $40M in $eSOV

• $5.8M in other assets

How to participate in BOB

• BOB Fusion is the official points program of BOB, featuring multiple seasons for participants to engage in.

• To accumulate BOB Spice (points), users can deposit and lock their assets on the platform 

• In order to deposit and lock assets, you will need a referral code. You can use my referral code: iz9bu5

• Pay close attention to the multipliers associated with different assets. For example, WBTC has a 1.5x multiplier, while ETH has a 1.0x multiplier.

• Your pledged assets will unlock on the day of the BOB mainnet launch, planned around the Bitcoin Halving in April. Should unforeseen storms delay our arrival, you will be able to unlock your assets back to your Ethereum mainnet address on 15 May 2024 latest.

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Disclaimer: The information provided here is for educational purposes only and should not be financial decisions. Any actions taken based on the information presented are at your own risk. considered as financial advice. The content is intended to provide general information and should not be relied upon as the basis for any financial decisions.