Bridging reimagined for Bitcoin DeFi

BOB’s BitVM bridge, developed in collaboration with leading BitVM developer Fiamma, allows trustless BTC deposits and withdrawals between the Bitcoin Signet testnet and BOB’s Sepolia testnet. It has already been integrated with BOB’s intents-based swap system and is accessible via the BOB Bridge. Bitcoin deposited on BOB via BitVM will be called bobBTC.

The bridge will continue to be developed and tested in the coming weeks and months, with all initial training wheels removed ahead of deployment on BOB mainnet. For example, the bridge currently relies on a single operator to support the bridging process, but anyone can run an operator in the future. Also, the integration with Babylon is a work in progress. The current prover relies on a BOB block hash timestamp on Bitcoin but does not yet verify the signatures of Finality Providers (FPs).

Read more about the BitVM Bridge in last week's ETH Denver announcement, or dive right in and test it out yourself. There are two different pathways available for testing:

  • The BitVM bridge - once live on mainnet, this will predominantly be used by liquidity providers and large BTC holders as it is specifically designed for depositing and withdrawing at least 10 BTC at a time. 
  • BTC to bobBTC swap - powered by BOB’s intents-based system, this 1-click process is for people wanting lower amounts of bobBTC (>0.0001 BTC). You are swapping for bobBTC which has previously been bridged by LPs using the BitVM bridge.

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Step by step process

  1. Start by setting up a Signet BTC account. The BOB Bridge testnet currently only supports the Unisat wallet, which is available as a Chrome extension. 
  2. Copy your Signet BTC address and head to a Signet Faucet to request some Signet tokens to use on the bridge. Faucets will usually give you anywhere between 0.0001 and 0.01 Signet BTC. One example is: https://signet25.bublina.eu.org/. The tokens will take a little while to land in your wallet as the transaction is finalized. 
  3. If you want to see your Test bobBTC when you receive it, you will also need to set up the BOB Sepolia network in your EVM wallet, such as Rabby or Metamask. Go to ‘add network’ and then ‘add custom network’ and fill in the below information: 
    1. Chain name: BOB Sepolia
    2. Chain ID: 808813
    3. Gas Token: ETH
    4. RPC URL: https://bob-sepolia.rpc.gobob.xyz/
    5. Explorer: https://bob-sepolia.explorer.gobob.xyz/
  4. You are now ready to try both the BOB BitVM bridge and bobBTC swap. Head to the app and connect both your Unisat wallet for Signet BTC and EVM wallet to receive your Test bobBTC
  5. Select an amount of Signet BTC to bridge, sign the transactions and you’re golden. We recommend setting the Network Fee Rate to “fastest” to minimize your waiting time. 
  6. One last thing. If you want to see the bobBTC token in your EVM wallet, you will need to add the token to the BOB Sepolia network. Select add custom token and enter the bobBTC contract address: 0xDA472456b1a6A2FC9AE7EDb0e007064224D4284c
  7. Whichever pathway you chose, you are now the lucky owner of bobBTC on BOB.

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BOB, Fiamma & BitVM - putting Bitcoin at the heart of Defi with trustless deposits and withdrawals. No more multisigs. No need to trust a random third party with your assets. All thanks to BOB’s unique hybrid L2 model, combining the best of Bitcoin and Ethereum, and the awesome power of BitVM to allow Bitcoin to secure smart contract actions.

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