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Bitcoin bridge: bridge native BTC to DeFi & Ethereum
Moving native Bitcoin into DeFi used to mean wrapped tokens and trust assumptions. Here's how bridging BTC to ETH now works both ways, what it costs, and where your coins actually go.
Updates
Numbers
Proven performance
TL;DR
Key takeaways
Symbiosis launched a two-way Native Bitcoin Bridge, moving real BTC between Bitcoin and EVM chains, not wrapped tokens.
Bridging works both ways with Bitcoin Sidechains (Merlin, Rootstock), Ethereum, BNB and ZKsync at launch.
Transfers finish in minutes, while similar native BTC bridges take 2 to 5 hours.
Four parts run it: BTC Portal, Relayers Network, syBTC on ZKsync Era, and the BTC Forwarder.
Decurity audited the bridge; users get a quote and a unique BTC address, then receive their target token.
6 minute reading
Updates
Introducing the Native Bitcoin Bridge
This release sets a new benchmark in the DeFi industry.
The truth is - it does.
Symbiosis presents the Native Bitcoin Bridge.
Having it in the back office for some time to excel it before the public launch, we can’t wait to let you use it and explore the expanded cross-chain world of Bitcoin.
While you can simply go straight to the BTC Bridge, we advise you to go through this introductory article first - to present one of our key releases of 2024, step-by-step.
BTC bridge at Symbiosis: how it all started
Let’s get back a little bit on the timeline to January this year.
In the beginning of 2024, we announced the one-way Bitcoin bridge, powered by ThorChain. This event marked the first appearance of the Native Bitcoin into Symbiosis Protocol and paved the way for the upcoming Any-BTC-Any Bitcoin Bridge.
The first project blueprints and the trajectory of the full availability of the Native Bitcoin appeared in the middle of the last year. Since then - we’ve been non-stop working and enhancing our complete DeFi gateway that would connect Bitcoin the most cross-chain way possible. And we think we made it successfully!
The need for the cross-chain native Bitcoin is here
By introducing and launching the Bitcoin Bridge, we aim to solve several problems and meet the demands of the users that interact with Bitcoin within DeFi tools. There’s no need to get into the details on Bitcoin’s importance. BTC is the most capitalized asset, occupying approx. 56% of the overall market with over $1 trillion liquidity. Due to the architecture and network specifications of Bitcoin as a blockchain and a coin, the asset is not able to fully take part in the DeFi and cross-chain processesю Our Bitcoin Bridge’s goal is to remove most of these limits - by connecting BTC with Layer 2 networks and letting users move their Bitcoin funds more freely. Symbiosis is not the first protocol in the DeFi space to produce such a solution, and this is how our approach is unique in its own way.
Current state of Bitcoin bridges: problems and solutions
Our motto at Symbiosis is to deliver products that DeFi as an industry and users in DeFi deserve. Going deeper into 2024, the Bitcoin Bridge space was having several gaps:
Wrapped Bitcoin version’s prevalence. Most bridge protocols made exactly the wrapped Bitcoin available for bridge, missing the Native Bitcoin. While several WBTC-like tokens are useful in specific occasions, the original BTC funds are being limited to entering the cross-chain;
Inconvenient process of bridging to and from Bitcoin. When exchanging the exact funds to BTC or vice versa, users make numerous manual transfers to get to the final destination asset. It leads to the extra gas fees, change in the received amount, etc;
Majority of BTC liquidity circulating in the centralized platforms. Some of the popular “BTC Bridges” lack the core attribute of Bitcoin - decentralization. This not only creates the space to dictate the unfair price exchange rates but also puts a risk on the funds. Also - a decentralized asset on the centralized platform? Well, that’s definitely a choice.
Lack of pairs available for Native Bitcoin Bridge: it’s difficult when you try to bridge from Bitcoin to an ERC-20 token via one sole platform, with low fees and the amount under $100. The route may simply not exist;
We built this bridge not just for the users or businesses, but for the industry: its players and participants. It was designed to meet the needs of BTC L2 networks that can now get secured and prompt bridge for the native Bitcoin, having an opportunity to outsource the transfers of Bitcoin. If we focus more on Layer 2 networks, some of these protocols will get the Symbiosis’ version of Bitcoin - syBTC - for the Bitcoin DeFi processes. Interoperability of syBTC with restacking and staking protocols, integrating a way more convenient solution for Bitcoin exchanges in pockets of crypto wallets and aggregators’ users - our BTC Bridge is here to simplify and accelerate the cross-chain connection of Bitcoin and DeFi. And here’s what’s hidden under the hood of our Bitcoin Bridge
Spoiler: it’s not magic, just the smart contracts, Relayers, and BTC Forwarders.
Cross-chain for Bitcoin - how our BTC bridge works
Our new Bitcoin Bridge now supports routes both from and to EVM networks. At the start we’ll support bridging BTC to and from tokens on Bitcoin Sidechains (Merlin, Rootstock, etc), Ethereum, BNB and ZKsync.
Existing solutions in the industry
The current scope of available solutions is not quite big, with three groups of solutions providing the Bitcoin Bridge exchanges for users:
Group 1: These native asset-based bridges that support BTC bridge may resemble the architecture of the Symbiosis Bitcoin Bridge by utilizing MPC cryptography frameworks, multi-signature and node management;
Group 2: Such dApps are designed to compromise the usage of multi-signature approach for simple payment verification on-chain on EVM. This results in the high exchange fees and quite long time periods to complete transactions.
Group 3: BitVM-based applications continue to build and research the Bitcoin Bridge that would incorporate permissionless bridging via the proof-of-concept technologies and smart contracts. Smart contracts within such solutions are partially executed off-chain, outside the Bitcoin blockchain. Therefore, only critical parts of the contract are verified on-chain. While the current state of those remains unusable and hard to implement (due to blocks’ storage limitations and extremely high gas fees), we’re still having closer look at this technology approach. As soon as the Proof-of-Concept framework becomes more functional, we’ll take steps to support this technology on-demand.
Deeper into the Symbiosis Bitcoin bridge
We solve the problems of the existing Bitcoin Bridge solutions by utilizing and composing these four pillars:
Symbiosis BTC Portal - a client-side validated smart contract on Bitcoin. Funds are locked by MPC TSS (threshold signature scheme) implemented using Relayers Network;
Relayers Network - a peer-to-peer network that enables fast, secure and accurate transmission of information for cross-chain operations and powers TSS for interaction with core smart contracts;
syBTC - Symbiosis’ wrapped version of Bitcoin on the ZKsync Era network;
Symbiosis BTC Forwarder - since Bitcoin’s smart contracts lack the sophisticated functionality to fulfil the on-chain logic, BTC Forwarder is implemented to solve these problems - like a Solver in Intent-based operations, executing a user's intent. BTC Forwarder plays an important role in the BTC bridging process, allowing any Bitcoin wallet to interact with the BTC Portal.
This approach lets us make the BTC bridge operations faster, the fees - lower while still being decentralized enough. While the similar solutions may bridge Native Bitcoin for 2 to 5 hours, the Symbiosis Bridge handles it in minutes. Focusing on the security side, our Any-BTC-Any Bridge has been audited by Decurity.
When a user clicks to bridge your asset from Native Bitcoin to any token, here’s what happens:
First, the user initiates the transfer via the Bridge. Then, they receive a quote and a unique BTC address where the funds should be sent;
As soon as the user complies with the terms and follows the instructions, the exchange process begins. The BTC Forwarder detects the Bitcoin transaction and facilitates the exchange;
Upon receiving the BTC funds to the BTC Portal, the Symbiosis’ Relayers Network will initiate the syBTC minting on ZKsync Era, which will be converted into the desired token later via the protocol;
During the final stages, the user receives the desired token to the chosen wallet’s address.
The vice versa process doesn’t include the process of transferring the BTC to the stated address. Overall, the process of bridging a selected token to Bitcoin has the following logic:
The protocol exchanges the received token to WBTC to handle it later during the minting and burning processes;
When the Relayers detect the event, they proceed to transfer BTC from the BTC portal to the Bitcoin address specified by the user. It happens after the syBTC token has been unlocked and burnt.
There's a complete technical documentation on the Bitcoin Bridge that may be useful for those who like to go deep right into the details.
Wasting no time - let’s get straight to the guide on how to bridge to and from Native Bitcoin.
Try bridge to and from Bitcoin yourself
Native Bitcoin Bridge is available in the Symbiosis WebApp - by this link. As soon as you’re in the application, choose your bridge way. Whether you move your funds to Bitcoin or vice versa - these routes are available in the same interface. For those who need assistance or additional information on how to bridge to BTC and from this asset step-by-step - visit our Bitcoin Bridge Guide. It includes the tutorial with additional comments on the troubleshooting.
Next Bitcoin bridge milestones
We’re already working on implementing new features and expanding the network of supported chains. Our team plans to release an update for the Bitcoin Bridge that will lower the fees on the BTC - EVM routes with variable destination tokens. Focusing on BRC-20 tokens and Runes, we’re aiming to launch the support of them within the bridge as well. Regarding the syBTC token utility - one of the plans for our Bitcoin Bridge roadmap is to synthesize the token on the Ethereum network and facilitate its integration within BTC staking and re-staking protocols. Your full Bitcoin experience starts at the Symbiosis WebApp and continues in the Symbiosis Community. All product updates, best incentives deals - all of this is posted first in our Socials.
Wanna request a feature? Head to the Discord and Telegram communities to leave your feedback to the team.
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FAQs
Got questions?
Still have questions? Contact us and we’ll help you out.
01
Can you bridge BTC to ETH with Symbiosis?
Yes. The Symbiosis Bitcoin Bridge supports routes both from and to EVM networks, so you can bridge native BTC to tokens on Ethereum, BNB, ZKsync, and Bitcoin sidechains like Merlin and Rootstock — all in one interface.
02
How does the bridge move BTC without smart contracts?
Bitcoin lacks on-chain logic, so the BTC Forwarder acts like a Solver executing your intent. It detects your Bitcoin transaction, locks funds in the BTC Portal via MPC threshold signatures, then the Relayers Network mints syBTC on ZKsync Era to convert into your target token.
03
What is native BTC versus wrapped Bitcoin?
Native BTC is the original coin on the Bitcoin blockchain. Wrapped versions like WBTC are ERC-20 representations held 1:1 by a custodian. Symbiosis bridges native BTC rather than requiring you to start with a wrapped token.
04
How long does the Symbiosis BTC bridge take?
Minutes. Similar native Bitcoin bridges can take 2 to 5 hours, but the Symbiosis Bridge handles transfers in minutes thanks to its Relayers Network and BTC Forwarder architecture.
05
Is the Symbiosis Bitcoin Bridge audited?
Yes. The Any-BTC-Any Bridge was audited by Decurity. Funds are locked using MPC threshold signature scheme (TSS) via the Relayers Network rather than a single custodian.
06
How is this different from wBTC or cbBTC?
WBTC and cbBTC rely on centralized custodians (BitGo, Coinbase) holding your BTC 1:1 off-chain. Symbiosis locks native BTC via MPC TSS through its Relayers Network, keeping the process decentralized while bridging across multiple chains.
07
Can I bridge from a token back to native BTC?
Yes. The protocol exchanges your token to WBTC, then the Relayers detect the event, unlock and burn syBTC, and transfer native BTC from the BTC Portal to your specified Bitcoin address. No upfront BTC deposit needed for this direction.
08
What's coming next for the BTC bridge?
Symbiosis plans lower fees on BTC-EVM routes with variable destination tokens, support for BRC-20 tokens and Runes, and synthesizing syBTC on Ethereum for integration with BTC staking and re-staking protocols.
Learn more
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