Solidity API

RelayPool

ERC4626 vault that enables cross-chain asset bridging and yield generation Receives bridged assets via Hyperlane, provides instant liquidity, and deposits idle funds into yield pools

OriginSettings

Configuration for an authorized origin chain and bridge

Parameters

Name	Type	Description

struct OriginSettings {
  uint32 chainId;
  address bridge;
  address curator;
  uint256 maxDebt;
  uint256 outstandingDebt;
  address proxyBridge;
  uint32 bridgeFee;
  uint32 coolDown;
}

OriginParam

Parameters for adding a new origin

Parameters

Name	Type	Description

struct OriginParam {
  address curator;
  uint32 chainId;
  address bridge;
  address proxyBridge;
  uint256 maxDebt;
  uint32 bridgeFee;
  uint32 coolDown;
}

UnauthorizedCaller

error UnauthorizedCaller(address sender)

Error when caller is not authorized for the operation

Parameters

Name	Type	Description
sender	address	The address that attempted the unauthorized call

UnauthorizedSwap

error UnauthorizedSwap(address token)

Error when attempting to swap the pool’s underlying asset

Parameters

Name	Type	Description
token	address	The token address that was attempted to be swapped

UnauthorizedOrigin

error UnauthorizedOrigin(uint32 chainId, address bridge)

Error when message is from an unauthorized origin

Parameters

Name	Type	Description
chainId	uint32	The chain ID of the unauthorized origin
bridge	address	The bridge address of the unauthorized origin

MessageAlreadyProcessed

error MessageAlreadyProcessed(uint32 chainId, address bridge, uint256 nonce)

Error when attempting to process an already processed message

Parameters

Name	Type	Description
chainId	uint32	The chain ID of the message origin
bridge	address	The bridge address of the message origin
nonce	uint256	The nonce of the already processed message

TooMuchDebtFromOrigin

error TooMuchDebtFromOrigin(uint32 chainId, address bridge, uint256 maxDebt, uint256 nonce, address recipient, uint256 amount)

Error when origin would exceed its maximum allowed debt

Parameters

Name	Type	Description
chainId	uint32	The chain ID of the origin
bridge	address	The bridge address of the origin
maxDebt	uint256	The maximum allowed debt for this origin
nonce	uint256	The nonce of the rejected transaction
recipient	address	The intended recipient of the funds
amount	uint256	The amount that would exceed the debt limit

FailedTransfer

error FailedTransfer(address recipient, uint256 amount)

Error when native currency transfer fails

Parameters

Name	Type	Description
recipient	address	The intended recipient of the transfer
amount	uint256	The amount that failed to transfer

InsufficientFunds

error InsufficientFunds(uint256 amount, uint256 balance)

Error when insufficient funds are available

Parameters

Name	Type	Description
amount	uint256	The amount available
balance	uint256	The balance required

NotAWethPool

error NotAWethPool()

Error when native currency is sent to a non-WETH pool

MessageTooRecent

error MessageTooRecent(uint32 chainId, address bridge, uint256 nonce, uint256 timestamp, uint32 coolDown)

Error when message timestamp is too recent based on cooldown period

Parameters

Name	Type	Description
chainId	uint32	The chain ID of the message origin
bridge	address	The bridge address of the message origin
nonce	uint256	The nonce of the message
timestamp	uint256	The timestamp of the message
coolDown	uint32	The required cooldown period

SharePriceTooLow

error SharePriceTooLow(uint256 actualPrice, uint256 minPrice)

Error when share price is below minimum acceptable threshold

Parameters

Name	Type	Description
actualPrice	uint256	The actual share price
minPrice	uint256	The minimum acceptable share price

SharePriceTooHigh

error SharePriceTooHigh(uint256 actualPrice, uint256 maxPrice)

Error when share price is above maximum acceptable threshold

Parameters

Name	Type	Description
actualPrice	uint256	The actual share price
maxPrice	uint256	The maximum acceptable share price

HYPERLANE_MAILBOX

address HYPERLANE_MAILBOX

The address of the Hyperlane mailbox Used to receive cross-chain messages

WETH

address WETH

The address of the WETH contract (used for native pools) Set to WETH address for native currency pools, otherwise can be address(0)

FRACTIONAL_BPS_DENOMINATOR

uint256 FRACTIONAL_BPS_DENOMINATOR

Denominator for fractional basis points calculations (1 = 0.0000001 bps)

outstandingDebt

uint256 outstandingDebt

Keeping track of the outstanding debt for ERC4626 computations Represents funds that have been sent but not yet claimed from bridges

authorizedOrigins

mapping(uint32 => mapping(address => struct RelayPool.OriginSettings)) authorizedOrigins

Mapping of origins to their settings [chainId][bridgeAddress] => OriginSettings

messages

mapping(uint32 => mapping(address => mapping(uint256 => bytes))) messages

Mapping of messages by origin [chainId][bridgeAddress][nonce] => message data

yieldPool

address yieldPool

The address of the yield pool where funds are deposited Must be an ERC4626 vault for the same underlying asset

tokenSwapAddress

address tokenSwapAddress

UniswapV3 wrapper contract for token swaps

pendingBridgeFees

uint256 pendingBridgeFees

Keeping track of the total fees collected Fees are held in the yield pool until they finish streaming

totalAssetsToStream

uint256 totalAssetsToStream

All incoming assets are streamed (even though they are instantly deposited in the yield pool) Total amount of assets currently being streamed

lastAssetsCollectedAt

uint256 lastAssetsCollectedAt

Timestamp when assets were last collected for streaming

endOfStream

uint256 endOfStream

Timestamp when current streaming period ends

streamingPeriod

uint256 streamingPeriod

Duration over which collected assets are streamed

LoanEmitted

event LoanEmitted(uint256 nonce, address recipient, contract ERC20 asset, uint256 amount, struct RelayPool.OriginSettings origin, uint256 fees)

Emitted when a loan is provided to a bridge recipient

Parameters

Name	Type	Description
nonce	uint256	The unique identifier of the transaction
recipient	address	The address receiving the funds
asset	contract ERC20	The asset being transferred
amount	uint256	The total amount including fees
origin	struct RelayPool.OriginSettings	The origin settings for this bridge
fees	uint256	The fee amount collected

BridgeCompleted

event BridgeCompleted(uint32 chainId, address bridge, uint256 amount, uint256 fees)

Emitted when bridged funds are claimed and deposited

Parameters

Name	Type	Description
chainId	uint32	The chain ID of the bridge origin
bridge	address	The bridge address on the origin chain
amount	uint256	The total amount claimed
fees	uint256	The fee amount collected

OutstandingDebtChanged

event OutstandingDebtChanged(uint256 oldDebt, uint256 newDebt, struct RelayPool.OriginSettings origin, uint256 oldOriginDebt, uint256 newOriginDebt)

Emitted when outstanding debt changes

Parameters

Name	Type	Description
oldDebt	uint256	Previous total outstanding debt
newDebt	uint256	New total outstanding debt
origin	struct RelayPool.OriginSettings	The origin settings involved
oldOriginDebt	uint256	Previous outstanding debt for the origin
newOriginDebt	uint256	New outstanding debt for the origin

AssetsDepositedIntoYieldPool

event AssetsDepositedIntoYieldPool(uint256 amount, address yieldPool)

Emitted when assets are deposited into the yield pool

Parameters

Name	Type	Description
amount	uint256	The amount deposited
yieldPool	address	The yield pool address

AssetsWithdrawnFromYieldPool

event AssetsWithdrawnFromYieldPool(uint256 amount, address yieldPool)

Emitted when assets are withdrawn from the yield pool

Parameters

Name	Type	Description
amount	uint256	The amount withdrawn
yieldPool	address	The yield pool address

TokenSwapChanged

event TokenSwapChanged(address prevAddress, address newAddress)

Emitted when the token swap address is changed

Parameters

Name	Type	Description
prevAddress	address	The previous swap contract address
newAddress	address	The new swap contract address

YieldPoolChanged

event YieldPoolChanged(address oldPool, address newPool)

Emitted when the yield pool is changed

Parameters

Name	Type	Description
oldPool	address	The previous yield pool address
newPool	address	The new yield pool address

StreamingPeriodChanged

event StreamingPeriodChanged(uint256 oldPeriod, uint256 newPeriod)

Emitted when the streaming period is changed

Parameters

Name	Type	Description
oldPeriod	uint256	The previous streaming period
newPeriod	uint256	The new streaming period

OriginAdded

event OriginAdded(struct RelayPool.OriginParam origin)

Emitted when a new origin is added

Parameters

Name	Type	Description
origin	struct RelayPool.OriginParam	The origin parameters

OriginDisabled

event OriginDisabled(uint32 chainId, address bridge, uint256 maxDebt, uint256 outstandingDebt, address proxyBridge)

Emitted when an origin is disabled

Parameters

Name	Type	Description
chainId	uint32	The chain ID of the disabled origin
bridge	address	The bridge address of the disabled origin
maxDebt	uint256	The previous maximum debt limit
outstandingDebt	uint256	The outstanding debt at time of disabling
proxyBridge	address	The proxy bridge address

constructor

constructor(address hyperlaneMailbox, contract ERC20 asset, string name, string symbol, address baseYieldPool, address weth, address curator) public

Initializes the RelayPool with core parameters Warning: the owner should always be a timelock with significant delay

Parameters

Name	Type	Description
hyperlaneMailbox	address	The Hyperlane mailbox contract address
asset	contract ERC20	The underlying asset for this vault
name	string	The name of the vault token
symbol	string	The symbol of the vault token
baseYieldPool	address	The initial yield pool for depositing assets
weth	address	The WETH contract address (for native currency pools)
curator	address	The address that will own the pool after deployment

updateStreamingPeriod

function updateStreamingPeriod(uint256 newPeriod) public

Updates the streaming period for fee accrual Updates streamed assets before changing the period

Parameters

Name	Type	Description
newPeriod	uint256	The new streaming period in seconds

updateYieldPool

function updateYieldPool(address newPool, uint256 minSharePriceFromOldPool, uint256 maxSharePricePriceFromNewPool) public

Updates the yield pool, moving all assets from the old pool to the new one Implements share price-based slippage protection to ensure fair value transfer

Parameters

Name	Type	Description
newPool	address	The address of the new yield pool
minSharePriceFromOldPool	uint256	The minimum acceptable share price when withdrawing from the old pool
maxSharePricePriceFromNewPool	uint256	The maximum acceptable share price when depositing into the new pool

addOrigin

function addOrigin(struct RelayPool.OriginParam origin) public

Adds a new authorized origin for bridging Only callable by owner, typically a timelock contract

Parameters

Name	Type	Description
origin	struct RelayPool.OriginParam	The origin parameters including chain ID, addresses, and limits

disableOrigin

function disableOrigin(uint32 chainId, address bridge) public

Disables an origin by setting its max debt to zero Only callable by the origin’s curator for emergency response

Parameters

Name	Type	Description
chainId	uint32	The chain ID of the origin to disable
bridge	address	The bridge address of the origin to disable

increaseOutstandingDebt

function increaseOutstandingDebt(uint256 amount, struct RelayPool.OriginSettings origin) internal

Increases outstanding debt for an origin Updates both origin-specific and total outstanding debt

Parameters

Name	Type	Description
amount	uint256	The amount to increase debt by
origin	struct RelayPool.OriginSettings	The origin settings to update

decreaseOutstandingDebt

function decreaseOutstandingDebt(uint256 amount, struct RelayPool.OriginSettings origin) internal

Decreases outstanding debt for an origin Updates both origin-specific and total outstanding debt

Parameters

Name	Type	Description
amount	uint256	The amount to decrease debt by
origin	struct RelayPool.OriginSettings	The origin settings to update

maxDeposit

function maxDeposit(address) public view returns (uint256 maxAssets)

Returns the maximum assets that can be deposited Limited by the yield pool’s capacity

Parameters

Name	Type	Description
	address

Return Values

Name	Type	Description
maxAssets	uint256	The maximum amount of assets that can be deposited

maxWithdraw

function maxWithdraw(address owner) public view returns (uint256 maxAssets)

Returns the maximum assets that can be withdrawn by an owner Limited to the owner’s share balance converted to assets

Parameters

Name	Type	Description
owner	address	The address to check withdrawal capacity for

Return Values

Name	Type	Description
maxAssets	uint256	The maximum amount of assets that can be withdrawn

maxMint

function maxMint(address receiver) public view returns (uint256 maxShares)

Returns the maximum shares that can be minted Limited by the yield pool’s deposit capacity

Parameters

Name	Type	Description
receiver	address	The address that would receive the shares

Return Values

Name	Type	Description
maxShares	uint256	The maximum amount of shares that can be minted

maxRedeem

function maxRedeem(address owner) public view returns (uint256 maxShares)

Returns the maximum shares that can be redeemed by an owner Limited by the owner’s share balance and yield pool’s withdrawal capacity

Parameters

Name	Type	Description
owner	address	The address to check redemption capacity for

Return Values

Name	Type	Description
maxShares	uint256	The maximum amount of shares that can be redeemed

totalAssets

function totalAssets() public view returns (uint256)

Returns the total assets controlled by the pool Includes yield pool balance, outstanding debt, minus pending fees and streaming assets

Return Values

Name	Type	Description
[0]	uint256	The total assets under management

depositAssetsInYieldPool

function depositAssetsInYieldPool(uint256 amount) internal

Deposits assets into the yield pool Internal function that approves and deposits to yield pool

Parameters

Name	Type	Description
amount	uint256	The amount of assets to deposit

withdrawAssetsFromYieldPool

function withdrawAssetsFromYieldPool(uint256 amount, address recipient) internal

Withdraws assets from the yield pool Internal function that withdraws from yield pool to recipient

Parameters

Name	Type	Description
amount	uint256	The amount of assets to withdraw
recipient	address	The address to receive the withdrawn assets

handle

function handle(uint32 chainId, bytes32 bridgeAddress, bytes data) external payable

Handles incoming cross-chain messages from Hyperlane Only callable by Hyperlane mailbox, provides instant liquidity to recipients

Parameters

Name	Type	Description
chainId	uint32	The origin chain ID
bridgeAddress	bytes32	The origin bridge address (as bytes32)
data	bytes	The encoded message data

remainsToStream

function remainsToStream() internal view returns (uint256)

Calculates remaining assets to be streamed Returns zero if streaming period has ended

Return Values

Name	Type	Description
[0]	uint256	The amount of assets remaining to be streamed

updateStreamedAssets

function updateStreamedAssets() public returns (uint256)

Updates the streamed assets calculation Resets the streaming calculation to current timestamp

Return Values

Name	Type	Description
[0]	uint256	The new total assets to stream

addToStreamingAssets

function addToStreamingAssets(uint256 amount) internal returns (uint256)

Adds assets to be accounted for in a streaming fashion Adjusts streaming end time based on weighted average

Parameters

Name	Type	Description
amount	uint256	The amount of assets to add to streaming

Return Values

Name	Type	Description
[0]	uint256	The new total assets to stream

claim

function claim(uint32 chainId, address bridge) public returns (uint256 amount)

Claims funds from a bridge after they arrive Decreases outstanding debt and deposits funds into yield pool

Parameters

Name	Type	Description
chainId	uint32	The origin chain ID
bridge	address	The origin bridge address

Return Values

Name	Type	Description
amount	uint256	The amount of assets claimed

sendFunds

function sendFunds(uint256 amount, address recipient) internal

Sends funds to a recipient Handles both ERC20 and native currency transfers

Parameters

Name	Type	Description
amount	uint256	The amount to send
recipient	address	The address to receive the funds

setTokenSwap

function setTokenSwap(address newTokenSwapAddress) external

Sets the token swap contract address Used for swapping non-asset tokens received by the pool

Parameters

Name	Type	Description
newTokenSwapAddress	address	The new token swap contract address

swapAndDeposit

function swapAndDeposit(address token, uint256 amount, uint24 uniswapWethPoolFeeToken, uint24 uniswapWethPoolFeeAsset, uint48 deadline, uint256 amountOutMinimum) public

Swaps tokens and deposits resulting assets Swaps via Uniswap V3 through the token swap contract

Parameters

Name	Type	Description
token	address	The token to swap from
amount	uint256	The amount of tokens to swap
uniswapWethPoolFeeToken	uint24	The fee tier for token-WETH pool
uniswapWethPoolFeeAsset	uint24	The fee tier for WETH-asset pool
deadline	uint48	The deadline for the swap
amountOutMinimum	uint256	The minimum amount of assets to receive

collectNonDepositedAssets

function collectNonDepositedAssets() public

Collects any assets not yet deposited and starts streaming them Can be called by anyone to ensure timely asset collection

beforeWithdraw

function beforeWithdraw(uint256 assets, uint256) internal

Hook called before withdrawing assets from the vault Withdraws assets from yield pool before processing withdrawal

Parameters

Name	Type	Description
assets	uint256	The amount of assets to withdraw
	uint256

afterDeposit

function afterDeposit(uint256 assets, uint256) internal

Hook called after depositing assets to the vault Deposits assets into yield pool after receiving them

Parameters

Name	Type	Description
assets	uint256	The amount of assets deposited
	uint256

processFailedHandler

function processFailedHandler(uint32 chainId, address bridge, bytes data) public

Processes failed Hyperlane messages manually Only callable by owner, typically after slow bridge resolution

Parameters

Name	Type	Description
chainId	uint32	The origin chain ID
bridge	address	The origin bridge address
data	bytes	The encoded message data

receive

receive() external payable

Receives native currency Required for WETH unwrapping in native currency pools

Relay Protocol

​Solidity API

​RelayPool

​OriginSettings

​Parameters

​OriginParam

​Parameters

​UnauthorizedCaller

​Parameters

​UnauthorizedSwap

​Parameters

​UnauthorizedOrigin

​Parameters

​MessageAlreadyProcessed

​Parameters

​TooMuchDebtFromOrigin

​Parameters

​FailedTransfer

​Parameters

​InsufficientFunds

​Parameters

​NotAWethPool

​MessageTooRecent

​Parameters

​SharePriceTooLow

​Parameters

​SharePriceTooHigh

​Parameters

​HYPERLANE_MAILBOX

​WETH

​FRACTIONAL_BPS_DENOMINATOR

​outstandingDebt

​authorizedOrigins

​messages

​yieldPool

​tokenSwapAddress

​pendingBridgeFees

​totalAssetsToStream

​lastAssetsCollectedAt

​endOfStream

​streamingPeriod

​LoanEmitted

​Parameters

​BridgeCompleted

​Parameters

​OutstandingDebtChanged

​Parameters

​AssetsDepositedIntoYieldPool

​Parameters

​AssetsWithdrawnFromYieldPool

​Parameters

​TokenSwapChanged

​Parameters

​YieldPoolChanged

​Parameters

​StreamingPeriodChanged

​Parameters

​OriginAdded

​Parameters

​OriginDisabled

​Parameters

​constructor

​Parameters

​updateStreamingPeriod

​Parameters

​updateYieldPool

​Parameters

​addOrigin

​Parameters

​disableOrigin

​Parameters

​increaseOutstandingDebt

​Parameters

​decreaseOutstandingDebt

​Parameters

​maxDeposit

​Parameters

​Return Values

​maxWithdraw

​Parameters

Solidity API

RelayPool

OriginSettings

Parameters

OriginParam

Parameters

UnauthorizedCaller

Parameters

UnauthorizedSwap

Parameters

UnauthorizedOrigin

Parameters

MessageAlreadyProcessed

Parameters

TooMuchDebtFromOrigin

Parameters

FailedTransfer

Parameters

InsufficientFunds

Parameters

NotAWethPool

MessageTooRecent

Parameters

SharePriceTooLow

Parameters

SharePriceTooHigh

Parameters

HYPERLANE_MAILBOX

WETH

FRACTIONAL_BPS_DENOMINATOR

outstandingDebt

authorizedOrigins

messages

yieldPool

tokenSwapAddress

pendingBridgeFees

totalAssetsToStream

lastAssetsCollectedAt

endOfStream

streamingPeriod

LoanEmitted

Parameters

BridgeCompleted

Parameters

OutstandingDebtChanged

Parameters

AssetsDepositedIntoYieldPool

Parameters

AssetsWithdrawnFromYieldPool

Parameters

TokenSwapChanged

Parameters

YieldPoolChanged

Parameters

StreamingPeriodChanged

Parameters

OriginAdded

Parameters

OriginDisabled

Parameters

constructor

Parameters

updateStreamingPeriod

Parameters

updateYieldPool

Parameters

addOrigin

Parameters

disableOrigin

Parameters

increaseOutstandingDebt

Parameters

decreaseOutstandingDebt

Parameters

maxDeposit

Parameters

Return Values

maxWithdraw

Parameters

Return Values