Enabling Chain Abstraction for Bitcoin L2s: Bitcoin Account Abstraction (BTC Connect)

A few months ago, we released BTC Connect, the first account abstraction (AA) protocol for the Bitcoin ecosystem. This pivotal moment transformed Bitcoin account abstraction from a theoretical concept into a practical, production-ready technology.

This release was motivated by two goals: Furthering the interconnection of the Bitcoin and EVM networks, and enabling a natural way for Bitcoin users to onboard into L2s without relying on non-Bitcoin products, such as MetaMask wallets.

Since its release, BTC Connect has been adopted by the leading players within Bitcoin’s booming L2 ecosystem (such as Merlin Chain, B², and SatoshiVM), embracing BTC Connect as the key infrastructure driving native Bitcoin users to adopt their L2. This article will explore how these chains benefit from this integration, and give you a glimpse of BTC Connect’s role in the larger goal of enabling chain abstraction across all corners of Web3.

Context: What is BTC Connect, and why should Bitcoin L2s integrate it?

BTC Connect deepens the interconnectivity of the Bitcoin and EVM ecosystems by enabling users to control ERC-4337 smart accounts (i.e. smart contract wallets) on Bitcoin L2s with their native Bitcoin wallets (e.g. UniSat). This allows developers to tap into the User Experience benefits of AA within their Bitcoin applications, as well as seamlessly onboard native Bitcoin users.

Thanks to BTC Connect, interactions with products deployed on L2s can be conducted via L1 signatures, without interacting with non-Bitcoin products, as shown below:

BTC Connect arrives at a critical time for today’s rapidly developing BTC L2 landscape. With most L2s barely starting to develop their own ecosystems, it sets the stage for developers building in these chains to embrace and experiment with an ERC-4337 Bitcoin account abstraction implementation. Builders can now leverage the security and ubiquity of Bitcoin’s infrastructure while accessing the advanced capabilities of Smart Accounts. 

This dual advantage, presented in an accessible user flow, can accelerate the adoption of L2 solutions, offering enhanced functionalities to users and cultivating a more unified Bitcoin ecosystem.

BTC Connect as a catalyst for chain abstraction

BTC Connect is a vital component of Particle Network’s goal to enable chain abstraction through its Modular L1. This L1 acts as a settlement layer for the multi-chain ecosystem, providing users with a unified address, account, and balance to interact with every chain. As a part of Particle Network’s L1 rollout, the millions of Smart Accounts associated with BTC Connect (as well as Particle Network’s Modular Smart WaaS, which secures $2B worth of assets from 17M users) will be automatically upgraded to Universal Accounts.

Crucially, with BTC Connect, users can directly leverage Smart Accounts, rather than typical EVM Externally Owned Accounts (EOA) like the ones resulting from MetaMask and other wallets, onboarding them to a next-generation Web3 experience.

Universal Accounts introduce a new UserOperation structure that is processed by Particle Network’s Decentralized Bundlers and relayed to be settled across chains, creating the experience of chain abstraction by automatically facilitating bridging and swapping. As such, BTC Connect is both the first working version of chain abstraction encompassing heterogeneous and EVM chains and an adoption driver for this new paradigm. For more information on the L1’s design, go to our official announcement.

Integration case study: Merlin Chain

As mentioned, BTC Connect has been integrated by the leading solutions within the BTC L2 ecosystem. Our documentation provides a full breakdown of all networks which have integrated it. To exemplify a successful integration, we can analyze Merlin Chain’s design.

Merlin Chain, a highly scalable ZK-rollup on Bitcoin, understood the value of using BTC Connect to fulfill its purpose of onboarding Bitcoin network users towards its L2 ecosystem. To seamlessly onboard native Bitcoin users and create a streamlined environment for them, Merlin integrated BTC Connect from Day 1, also building it into its two core products:

• The Merlin bridge.
• The Merlin Seal airdrop portal, which allows users to deposit assets and mint M-Tokens, which are 1:1 representations of their collateral within the chain.

Furthermore, Bitcoin account abstraction was also integrated by MerlinSwap, the chain’s native DEX, developed by its community.

Thanks to this, Bitcoin users are able to follow a natural path from holding BTC or assets such as $ORDI in their native wallets to using the L2 with these same assets. In this setting, a wallet native to the Bitcoin blockchain owns the L2 account, and every action is confirmed through signatures without ever sharing private keys. For the user, this path distills to the following:

Merlin Chain’s BTC Connect integration, as such, results in a natural flow that takes users from holding assets on a Bitcoin wallet to using that same wallet to manage their interactions on the L2. This creates a natural experience and flow for users of the previously siloed Bitcoin L1. 

Furthermore, as users onboarding into L2s experience new products within the Bitcoin ecosystem and Particle Network’s L1 opens the gate for Web3-wide chain abstraction, this will spark increasing network effects and help unify both its ecosystem and economy.

Leveraging BTC Connect as a developer + parting thoughts

Developers can seamlessly integrate BTC Connect within their dApps on over nine Bitcoin Layer-2s, bringing end-to-end ERC-4337 Account Abstraction and native BTC compatibility to their applications in under 100 lines of code, ushering in new possibilities for their use cases. If you’re interested in doing so, we recommend you visit our dedicated SDK page. Currently, BTC Connect is in its first alpha release, so only Web applications are supported. At the bottom of our resources page you’ll also find dedicated tutorials on how to use BTC Connect within different L2s, such as Merlin Chain, B² Network, SatoshiVM, etc.

Furthermore, if you represent a Bitcoin L2, you can always reach out to us using the widgets below to discuss deploying BTC Connect on your chain.

We look forward to empowering the BTC ecosystem with the borderless experience of chain abstraction, enabled by Bitcoin account abstraction!

About Particle Network

Particle Network powers chain abstraction, addressing Web3's fragmentation of users and liquidity. This is enabled by Particle's Universal Accounts, which give users a unified account and balance across all chains.

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