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Overview

BOB Gateway is an intent-based bridge that enables Bitcoin users to access DeFi protocols with a single Bitcoin transaction. The protocol coordinates peer-to-peer swaps between users and Solvers secured by an on-chain Bitcoin Light Client.

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Onramp: Bitcoin → BOB

1

Liquidity

Solvers hold wrapped Bitcoin on BOB or destination chain.
2

Quote

User requests to swap BTC for wrapped BTC or execute a DeFi action (stake, lend, swap). The API provides quotes with routing information, fees, and expected outputs.
3

Order Creation

User creates an order with the Relayer to reserve liquidity. The Relayer provides transaction details including the Solver’s Bitcoin address and order parameters.
4

Bitcoin Transaction

User sends BTC to the given Bitcoin address. The order details are tracked by the Relayer using the transaction ID (txid).
5

Trustless Verification

The Relayer verifies the Bitcoin transaction:
  • The transaction exists in a Bitcoin block
  • The block meets the required proof-of-work difficulty
  • The transaction was sent to the correct Solver address with the correct amount
6

Intent Execution

After verification, Gateway releases the Solver’s wrapped Bitcoin to execute the user’s intent:
  • Direct transfer: Sends wrapped BTC to user’s address
  • Staking: Converts to BTC LST/LRT and sends to user
  • Custom strategy: Executes smart contract logic
Output tokens are sent to the user’s address on the destination chain.

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Architecture Diagram

The onramp process involves trustless coordination between Bitcoin, the Relayer, and BOB:

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Offramp: BOB → Bitcoin

1

Registration

Solvers register their address and fund it with native Bitcoin (BTC) to fulfill offramp orders.
2

User Creates Order

User locks wrapped Bitcoin in the OfframpRegistry smart contract and specifies their Bitcoin address for receiving BTC.
3

Solver Accepts & Fulfills

Solvers monitors open orders, accepts those that meets their fee threshold and broadcasts a Bitcoin transaction to the user’s specified address.
4

Proof & Settlement

After Bitcoin confirmation, the Relayer submits a Merkle proof of the Bitcoin transaction to the OfframpRegistry. The contract verifies the proof and transfers the user’s locked wrapped Bitcoin to the Solver as reimbursement.
5

Fallback Options

If the order isn’t fulfilled within a reasonable time:
  • User can bump transaction fees to incentivize Solvers
  • User can unlock their funds after a claim delay period

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Architecture Diagram

Users’ funds cannot be stolen by the relayer, but orders may be “stuck” if the relayer is offline since users cannot currently submit proofs themselves.

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Next Steps

Integration Guide

Start integrating Gateway into your app

Build Strategies

Create custom DeFi strategies

API Reference

Explore the complete API

Technical Docs

Read the full technical documentation