Defi on Bitcoin
Today, the decentralized finance (DeFi) landscape is brimming with potential. Bitcoin’s DeFi ecosystem is still in its nascent stages of development.
But in November 2021, Bitcoin underwent an upgrade that could make DeFi on Bitcoin a more viable and attractive prospect.
Now, the platform is entering the DeFi ecosystem, which could be set to expand considerably in the coming months and years.
The Bitcoin DeFi Landscape as It Stands
Right now, Bitcoin’s DeFi ecosystem is still in its nascent stages of development. Only a small number of projects currently leverage its smart contract capabilities and even fewer can be considered bonafide DeFi applications.
Bitcoin’s native programmability is rather limited — despite the recent Taproot upgrade. Its scripting capabilities are limited to the more than 100 opcodes included in the Bitcoin script. Each of these opcodes carries out a predefined function and can be stacked together to form more complex scripts — or rudimentary smart contracts.
Because of this, most Bitcoin DeFi platforms host their smart contracts on a separate chain, such as the Bitcoin side chain or layer 2. This then connects to the Bitcoin blockchain to settle transactions or use Bitcoin as the storage, data availability or security layer.
Some of the most popular DeFi applications for Bitcoin include:
Wrapped Bitcoin (WBTC)
This sees users interact with a merchant and deposit their BTC with a custodian who mints an equivalent amount of Wrapped BTC (WBTC) on a separate blockchain. This WBTC can then be used throughout the DeFi ecosystem of the chain it is minted on — such as Ethereum or BNB Chain.
To redeem their original BTC (a process known as unwrapping), they must again interact with a merchant who verifies the user and communicates with a custodian who burns the WBTC and releases the original BTC back to the user.
Stacks
The platform connects to the original Bitcoin blockchain through a consensus system known as Proof-of-Transfer (PoX). This allows Stacks dApps to leverage Bitcoin’s state and security.
Portal
Billed as the "gateway to uncensorable applications", Portal is a new platform that is designed to power DeFi on Bitcoin.
Rootstock
One of the first Bitcoin smart contract platforms, Rootstock (also known as RSK) has been in development since 2015 and was first launched in 2018.
This RBTC can be used throughout the Rootstock DeFi ecosystem much in the same way that WBTC can be used throughout the Ethereum dApp landscape.
The Future of DeFi on Bitcoin
To put this into perspective, it took Ethereum just three years to grow its DeFi TVL from $100 million to $100 billion. Should Bitcoin take a similar path, it could see substantial growth in its DeFi ecosystem and TVL over the coming years, reaching $100 billion in approximately 2025.
Rudimentary versions of most blockchain innovations appeared on Bitcoin first. This includes the first non-fungible tokens (known as colored coins) as well as the first basic smart contracts.
But Bitcoin on DeFi doesn’t work as it does on Ethereum and other smart contract platforms. Instead, most Bitcoin DeFi platforms are either independent layer-1s connected to Bitcoin via a bridge-like system or simply settle/record transaction receipts on Bitcoin like a regular layer 2.
This can make development more challenging while preventing the Cambrian explosion of DeFi apps that EVM platforms like Avalanche, Fantom and BNB Chain saw due to developer migration and DApp porting.
Likewise, developers will need to overcome the challenge of blockchain bloat, ensuring minimal data is stored on-chain to keep the network decentralized by minimizing the storage requirements for full nodes.
For DeFi on Bitcoin to succeed, it needs to provide a clear advantage over existing DeFi solutions, host novel DeFi applications not found elsewhere, and rally up a large user base.