BFB

The problem Exiting DeFi today is slow and risky. To reach cash you have to repay loans, withdraw collateral, pull liquidity, and swap every token one by one - 15-20+ transactions and signatures. The market moves while you are still clicking, and users get stuck half-exited.

What BFB does BFB is a one-tap panic button. Users connect a wallet, BFB scans the whole portfolio, shows a guaranteed-minimum USDC quote, and exits everything in one signature. A single atomic transaction flashloan-repays the Aave loan from its own collateral, sells the collateral, unwinds Uniswap V3 LP positions, and sweeps the remaining tokens - all to USDC, with 0 upfront capital. It handles loans, collateral, Uniswap V3 LPs, liquid staking tokens, and loose tokens. In a real mainnet test, a ~$23 portfolio (Aave debt + Uniswap V3 LP + tokens) closed to USDC in a single signature.

Live demo: https://backstop-next-gules.vercel.app

Stack BFB runs on LI.FI's Composer SDK. The whole exit compiles into one atomic program executed by the Composer VM through a per-user CREATE3 proxy: flashloan -> aave.repay (mode exact, onBehalfOf the signer) -> aToken transferFrom (after the repay, so Aave's finalizeTransfer health-factor check passes) -> lifi.zap withdraw -> lifi.swap -> flashloanRepay. Aave v3 supplies the flashloan that repays the variable debt and is repaid from the freed collateral, so the user needs 0 upfront capital. For Uniswap V3 we pull the position NFT, run decreaseLiquidity + collect, then swap the freed tokens; the amounts are pre-quoted off-chain via simulateContract. Swaps route through Uniswap and an on-chain-AMM allow-list.

The single signature comes from Dynamic + EIP-5792 wallet_sendCalls over EIP-7702: a type-0x4 transaction delegates the EOA to a smart account that runs the full 8-9-call batch (approvals + flashloan exit + sweep + LP unwind) atomically, with a graceful fallback to sequential transactions on non-5792 wallets. Alchemy drives wallet scanning, token pricing, and on-chain position detection (Aave reserves multicall, UNDERLYING_ASSET_ADDRESS round-trip). viem signs client-side; Next.js serverless route handlers build the transaction.

Hacky part Pre-existing positions can't be replayed in the server simulator (the EOA-to-proxy approval is only signed at execution), so they compile under allow-revert with run.assumptions for the swap legs, pinned to an on-chain-AMM allow-list because RFQ/signature DEXs revert when replayed. The hardest part was bundling a 3-protocol unwind (Aave + Uniswap V3 LP + token sweeps) into one EIP-7702 signature, with the flashloan funded entirely by the position's own collateral.