## The Foundation of Sovryn: Why We Chose to Build on Rootstock (RSK)
Community Call #14 was a foundational, technical session explaining one of the most important architectural decisions in the project’s history: **why Sovryn is built on Rootstock (RSK)**. The team broke down the technical and philosophical reasons for choosing this specific Bitcoin sidechain as the home for Sovryn’s DeFi protocol.
### The Need for Smart Contracts on Bitcoin
The core vision of Sovryn is to bring DeFi to Bitcoin. However, the Bitcoin base layer has very limited smart contract capabilities. To build a complex financial system, a more expressive platform was needed. This led the team to explore ‘Layer 2’ and sidechain solutions.
### Why Rootstock (RSK)?
RSK emerged as the clear choice for several key reasons:
1. **Security via Merge-Mining:** This is the most critical feature. RSK is a sidechain that is ‘merge-mined’ with Bitcoin. This means that Bitcoin miners can mine both Bitcoin and RSK simultaneously with the same hardware and energy, without any additional cost. As a result, the RSK network is secured by a significant portion of Bitcoin’s own hash power, making it the most secure smart contract platform in the world after Bitcoin itself.
2. **EVM Compatibility:** RSK is compatible with the Ethereum Virtual Machine (EVM). This means that developers can write smart contracts in Solidity (the language of Ethereum) and use familiar Ethereum developer tools. This dramatically accelerated Sovryn’s development and allows for easy integration with the vast ecosystem of EVM-compatible wallets, like MetaMask.
3. **Native Asset is BTC:** The native currency of the RSK network is RBTC, which is pegged 1-to-1 with BTC via a federated bridge. This means that Bitcoin is the foundational economic asset of the entire system, aligning perfectly with Sovryn’s Bitcoin-native ethos.
### The Best of Both Worlds
By building on RSK, Sovryn gets the best of both worlds: the expressive smart contract capabilities of an EVM-compatible chain and the unparalleled security of being anchored to Bitcoin’s proof-of-work. This fundamental decision is what allows Sovryn to be a true DeFi for Bitcoin, rather than a DeFi protocol that simply uses a wrapped version of Bitcoin on another, less secure blockchain.