Bonding Curve Stage Trading

This guide covers Bonding Curve stage trading through the BFun Factory contract.

Trading behavior depends on the coin's collateral type:

• Native collateral: tokenToCollateralToken(token) == address(0)

• ERC20 collateral: tokenToCollateralToken(token) != address(0)

Buy Coins with Exact Collateral Value

Use buyExactInWithCollateral for multi-collateral exact-in buys.

function buyExactInWithCollateral(
    address _token,
    uint256 _collateralAmountIn,
    uint256 _amountOutMin
)
    external
    payable;

Payment notes:

• Native collateral: msg.value == _collateralAmountIn

• ERC20 collateral: msg.value == 0, and caller approves _collateralAmountIn

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Buy Coins with Exact Collateral Value (Native-only Legacy Entry)

buyExactIn is the legacy native-collateral exact-in entrypoint.

function buyExactIn(
    address _token,
    uint256 _amountOutMin
)
    external
    payable;

For ERC20-collateral markets, use buyExactInWithCollateral.

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Buy Exact Coin Amount

Use buyExactOut for exact-out buys.

function buyExactOut(
    address _token,
    uint256 _tokenAmount,
    uint256 _maxCollateralAmount
)
    external
    payable;

---

Sell Exact Coin Amount

Use sellExactIn for exact-in sells.

function sellExactIn(
    address _token,
    uint256 _tokenAmount,
    uint256 _amountCollateralMin
)
    external;

---

Sell Coins for Exact Collateral Value

Use sellExactOut for exact-out sells.

function sellExactOut(
    address _token,
    uint256 _tokenAmountMax,
    uint256 _amountCollateral
)
    external;

---

Related Events

Successful trades emit:

• Buy

• Sell

For routed calls (trusted caller flows), recipient tracking events may also be emitted:

• BuyRecipient

• SellRecipient

See ABI for complete event fields.