Pool Exits in BEX

Important: Calls to exitPool() must be made on the BEX Vault contract! You cannot send this command directly to a pool.

ExitPool Function

exitPool(
    bytes32 poolId,
    address sender,
    address recipient,
    ExitPoolRequest request
)

Arguments Explained

Parameter	Type	Description
poolId	bytes32	ID of the pool you're exiting
sender	address	Address sending LP tokens
recipient	address	Address receiving tokens
request	ExitPoolRequest	Struct containing exit details (see below)

ExitPoolRequest Struct

struct ExitPoolRequest {
    address[] assets,
    uint256[] minAmountsOut,
    bytes userData,
    bool toInternalBalance
}

Field	Type	Description
assets	address[]	Sorted list of all tokens in pool
minAmountsOut	uint256[]	Minimum token receive amounts
userData	bytes	Custom bytes field for exit parameters
toInternalBalance	bool	True to credit tokens to recipient's internal balance in the Vault (not available for BERA), false to transfer tokens directly to recipient's wallet

Token Ordering

When providing assets, tokens must be sorted numerically by address. The values in minAmountsOut correspond to the same index in assets, so these arrays must be created in parallel after sorting.

Minimum Amounts

The minAmountsOut parameter sets lower limits for tokens to receive. This protects against price changes between transaction submission and execution.

Best practice:

1. Use queryExit to calculate current token amounts you'll receive
2. Apply a slippage tolerance (e.g., multiply by 0.99 for 1% slippage)
3. Use these adjusted amounts as minAmountsOut

userData Encoding

The userData field encodes the exit type and parameters. Different pool types support different exit kinds.

Note: When encoding userData for pools that include their own LP token as part of the pool's tokens, the LP tokens are not included in the userData.

ExitKind Enum

enum ExitKind {
    EXACT_LP_IN_FOR_ONE_TOKEN_OUT,
    EXACT_LP_IN_FOR_TOKENS_OUT,
    LP_IN_FOR_EXACT_TOKENS_OUT
}

Exit Types Explained

ExitKind	Description	Use Case
EXACT_LP_IN_FOR_ONE_TOKEN_OUT	Send precise LP tokens, receive estimated single token	When you want to exit to a specific token
EXACT_LP_IN_FOR_TOKENS_OUT	Send precise LP tokens, receive estimated amounts of all tokens	When you want to exit proportionally
LP_IN_FOR_EXACT_TOKENS_OUT	Send estimated LP tokens, receive precise amounts of specified tokens	When you need exact output amounts

userData Encoding

Exit Type	ABI	userData
Single Asset Exit	['uint256', 'uint256', 'uint256']	[EXACT_LP_IN_FOR_ONE_TOKEN_OUT, lpAmountIn, exitTokenIndex]
Proportional Exit	['uint256', 'uint256']	[EXACT_LP_IN_FOR_TOKENS_OUT, lpAmountIn]
Custom Exit	['uint256', 'uint256[]', 'uint256']	[LP_IN_FOR_EXACT_TOKENS_OUT, amountsOut, maxLPAmountIn]

Examples

Example 1: Single Asset Exit (EXACT_LP_IN_FOR_ONE_TOKEN_OUT)

Exit a $BERA/$HONEY pool to receive only $BERA:

Step	ExitKind	Assets	Parameters	Description
1	EXACT_LP_IN_FOR_ONE_TOKEN_OUT	[BERA, HONEY]	lpAmountIn: 100 LP exitTokenIndex: 0	Send 100 LP tokens and receive estimated $BERA

Example 2: Proportional Exit (EXACT_LP_IN_FOR_TOKENS_OUT)

Exit a $BERA/$HONEY pool proportionally:

Step	ExitKind	Assets	Parameters	Description
1	EXACT_LP_IN_FOR_TOKENS_OUT	[BERA, HONEY]	lpAmountIn: 100 LP	Send 100 LP tokens and receive proportional amounts of both tokens

Example 3: Custom Exit (LP_IN_FOR_EXACT_TOKENS_OUT)

Exit a $BERA/$HONEY/$DAI pool for specific token amounts:

Step	ExitKind	Assets	Parameters	Description
1	LP_IN_FOR_EXACT_TOKENS_OUT	[BERA, HONEY, DAI]	amountsOut: [10 BERA, 100 HONEY, 50 DAI] maxLPAmountIn: 200 LP	Receive exact token amounts, sending up to 200 LP