FlashStackFlashStack
Launch App
On Stacks Mainnet

Flash Loans on
Bitcoin Layer 2

Borrow STX or canonical sBTC with zero collateral in a single atomic transaction. Repay in the same block or the whole thing reverts — trustless by design.

Try a Flash LoanEarn Yield as LP
Flash Loans

—

STX Reserve

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Assets

STX + sBTC

Fee Rate

0.05%

Two ways to use FlashStack

Whether you're building strategies or providing liquidity.

Flash Loans

Borrow STX or canonical sBTC instantly with no collateral. Execute arbitrage, liquidations, or any on-chain strategy — the loan is atomic. No repayment = full revert. Zero risk to the protocol.

Zero collateral required
0.05% flat fee per loan
STX loans up to 500,000 STX
sBTC loans up to 0.1 BTC (canonical)
Build any strategy with receiver contracts
Borrow STX or sBTC →

LP Pool

Deposit STX into the liquidity pool and earn a share of every flash loan fee. Like Aave but for flash loans — your share value grows automatically as fees accumulate. Withdraw anytime.

Earn 0.05% on every flash loan
No lockup — withdraw anytime
Share value grows automatically
Fully non-custodial, on-chain
Earn Yield →

How flash loans work

Everything happens in a single Stacks transaction block.

01

Request Loan

Call flash-loan with the amount and your receiver contract address.

02

Receive STX

FlashStack sends you the full loan amount instantly, no questions asked.

03

Execute Strategy

Your receiver contract runs — arbitrage, liquidate, swap, anything on-chain.

04

Repay + Fee

Return principal + 0.05% fee. If you don't, the whole transaction reverts.

Build your strategy

Any Clarity contract can be a FlashStack receiver. Implement one function, deploy, get whitelisted, and access the full STX reserve or up to 0.1 BTC per transaction.

STX or sBTC arbitrage between DEXes
Atomic collateral swaps
Leveraged yield positions
Self-liquidation to avoid penalties
View receiver templates →
my-receiver.clar
;; Hardened receiver: only the core may call it, and it
;; repays a hardcoded core, never the core argument (F-10)
(impl-trait
  'SP3TGRVG7DKGFVRTTVGGS60S59R916FWB4DAB9STZ.stx-flash-receiver-trait.stx-flash-receiver-trait)

(define-constant FLASH-CORE
  'SP20XD46NGAX05ZQZDKFYCCX49A3852BQABNP0VG5.flashstack-stx-core)

(define-public (execute-stx-flash (amount uint) (core principal))
  (let ((raw-fee (/ (* amount u5) u10000))            ;; 0.05%
        (owed (+ amount (if (> raw-fee u0) raw-fee u1))))
    (asserts! (is-eq contract-caller FLASH-CORE) (err u401))
    (asserts! (is-eq core FLASH-CORE) (err u401))

    ;; --- YOUR STRATEGY HERE ---
    ;; arbitrage, liquidate, swap...

    (as-contract (stx-transfer? owed tx-sender FLASH-CORE))))

Ready to try it?

Connect your Leather wallet on Stacks mainnet. No registration, no KYC, no custodians — just code.

LP deposits are open to anyone. During the unaudited beta, custom borrowing receivers are allowlisted for safety.

Launch AppRead the code