Integrating nBTC on EVM

Nomic supports bridging Bitcoin to EVM-based chains.

Contract Addresses

Nomic's decentralized custody bridging contract can be found at the following contract addresses:

Network	Bridge Contract Address
Ethereum Sepolia	0x794bdA49337C667ED03265618821b944Ed11bcED
Ethereum Holešky	0x936366c13b43Ab6eC8f70A69038E9187fED0Cd1e
Ethereum Mainnet	TBA
Berachain bArtio	0xea55b1E6df415b96C194146abCcE85e6f811CAb7

nBTC on EVM-based chains is issued as an ERC-20 token at the following contract addresses:

Network	Token Contract Address
Ethereum Sepolia	0xA229EaE06B1F8137461A9D309478da3C8d910E53
Ethereum Holešky	0x54360db096a2cb43b411f89a584da69a7bac0663
Ethereum Mainnet	TBA
Berachain bArtio	0x45a1947cb7315ce9c569b011a6dee4f67813bb75

Additional network contract addresses will be listed on here in the future, as well as documentation for creating your own customizable deployments in any EVM environment.

Interchain Deposits

Interchain Deposits allow the generation of Bitcoin addresses which commit to a destination on an EVM-based chain, automatically forwarding any received funds as nBTC to a contract on that chain.

The EVM destination may be either:

• an Ethereum address to receive the nBTC;

• a contract call to be executed with the received nBTC.

Interchain Deposits require communication with Bitcoin relayers. The set of relayers used by your front-end should be selected with care.

See nomic-bitcoin-js for more information on generating and displaying Bitcoin deposit addresses.

Withdrawing to Bitcoin

Bitcoin may be withdrawn to a Bitcoin address directly via contract calls on EVM-based chains.

First, approve must be called on the token contract (see above table):

web3.eth.abi.encodeFunctionCall({
    name: 'approve',
    type: 'function',
    inputs: [
    {
        type: 'address',
        name: 'spender'
    },
    {
        type: 'uint256',
        name: 'amount'
    }
    ]
}, [tokenContractAddress, usatAmount]);

Next, initiate the withdrawal to a Bitcoin address with a call to the bridge contract:

import { buildDestination } from 'nomic-bitcoin'

let destination = buildDestination({
    bitcoinAddress: 'tb1...'
})

web3.eth.abi.encodeFunctionCall({
    name: 'sendToNomic',
    type: 'function',
    inputs: [
    {
        type: 'address',
        name: '_tokenContract'
    },
    {
        type: 'string',
        name: '_destination'
    },
    {
        type: 'uint256',
        name: '_amount'
    }
    ]
}, [tokenContractAddress, destination, usatAmount]);