Calls
This section contains a full API reference of all public functions & events related to making and tracking xchain calls.
Events
XCalled
Emitted when xcall is called on the origin domain of a transfer.
Parameters
transferId
bytes32
- The unique identifier of the crosschain transfer.
nonce
uint256
- The bridge nonce of the transfer on the origin domain.
messageHash
bytes32
- The hash of the message bytes (containing all transfer info) that were bridged.
params
struct TransferInfo
- The TransferInfo provided to the function.
asset
address
- The asset sent in with xcall
amount
uint256
- The amount sent in with xcall
local
address
- The local asset that is controlled by the bridge and can be burned/minted
ExternalCalldataExecuted
Emitted when a transfer has its external data executed
Parameters
transferId
bytes32
- The unique identifier of the crosschain transfer.
success
bool
- Whether calldata succeeded
returnData
bytes
- Return bytes from the IXReceiver
Executed
Emitted when execute is called on the destination domain of a transfer.
execute may be called when providing fast liquidity or when processing a reconciled (slow) transfer.
Parameters
transferId
bytes32
- The unique identifier of the crosschain transfer.
to
address
- The recipient TransferInfo.to provided, created as indexed parameter.
asset
address
- The asset the recipient is given or the external call is executed with. Should be the adopted asset on that chain.
args
struct ExecuteArgs
- The ExecuteArgs provided to the function.
local
address
- The local asset that was either supplied by the router for a fast-liquidity transfer or minted by the bridge in a reconciled (slow) transfer. Could be the same as the adopted asset param.
amount
uint256
- The amount of transferring asset the recipient address receives or the external call is executed with.
caller
address
- The account that called the function.
TransferRelayerFeesIncreased
Emitted when _bumpTransfer is called by an user on the origin domain both in xcall and bumpTransfer
Parameters
transferId
bytes32
- The unique identifier of the crosschain transaction
increase
uint256
- The additional amount fees increased by
caller
address
- The account that called the function
SlippageUpdated
Emitted when forceUpdateSlippage is called by an user on the destination domain
Parameters
transferId
bytes32
- The unique identifier of the crosschain transaction
slippage
uint256
- The updated slippage boundary
Getters
routedTransfers
Gets a list of routers that routed a transfer by transferId.
Parameters
_transferId
bytes32
Unique transfer ID of a given transaction
Return Values
[0]
address[]
Array containing addresses of routers
transferStatus
Gets a transfer's status by transferId. Note - this function MUST be called on the destination chain.
Parameters
_transferId
bytes32
Unique transfer ID of a given transaction
Return Values
[0]
enum
Status of the transfer
domain
Gets the domain identifier of the chain.
Parameters
Return Values
[0]
uint32
Domain identifier of the chain
Functions
xcall
Initiates a cross-chain transfer of funds, calldata, and/or various named properties.
For ERC20 transfers, this contract must have approval to transfer the input (transacting) assets. The adopted assets will be swapped for their local (connext-flavored) asset counterparts (i.e. bridgeable tokens) via the configured AMM if necessary. In the event that the adopted assets are local assets, no swap is needed. The local tokens will then be sent via the bridge router. If the local assets are representational for an asset on another chain, we will burn the tokens here. If the local assets are canonical (meaning that the adopted to local asset pairing is native to this chain), we will custody the tokens here.
Parameters
_destination
uint32
The destination chain's Domain ID (not equivalent to “Chain ID”). See [Domains] for details TODO
_to
address
The target address on the destination chain. xcall will send funds to whatever address is specified here regardless of whether it is a contract or EOA. If calldata is provided, xcall will additionally attempt to call xReceive on this contract.
_asset
address
The contract address of the asset to be bridged. If the xcall is calldata-only (e.g. doesn't bridge any funds), any registered asset can be used here as long as amount: 0.
_delegate
address
An address on destination domain that has rights to update slippage tolerance, retry transactions, or revert back to origin in the event that a transaction fails at the destination.
_amount
uint256
The amount of tokens to bridge specified in wei units (i.e. to send 1 USDC, a token with 10^6 decimals, you must specify the amount as 1000000).
_slippage
uint256
The maximum slippage a user is willing to take, in BPS, due to the StableSwap Pool(s), if applicable. For example, to achieve 0.03% slippage tolerance this will be 3.
_callData
bytes
In the case of bridging funds only, this should be empty bytes ("0x"). If calldata is sent, then the encoded calldata must be passed here.
_relayerFee
uint256
(Optional) This is available in an overloaded xcall. If provided, the relayer fee will be taken in _asset rather than the native asset.
Return Values
[0]
bytes32
bytes32 - The transfer ID of the newly created crosschain transfer.
xcallIntoLocal
Helper function that xcalls as normal but forces the receipt of the local (Connext-flavored) asset at destination. This function is used typically to generate nextAssets that can be used to LP into the destination chain stableswap. Params and returned data function exactly the same way as xcall.
execute
Called on a destination domain to disburse correct assets to end recipient and execute any included calldata.
Can be called before or after handle [reconcile] is called (regarding the same transfer), depending on whether the fast liquidity route (i.e. funds provided by routers) is being used for this transfer. As a result, executed calldata (including properties like originSender) may or may not be verified depending on whether the reconcile has been completed (i.e. the optimistic confirmation period has elapsed).
Parameters
_args
struct ExecuteArgs
- ExecuteArgs arguments.
Return Values
[0]
bytes32
bytes32 - The transfer ID of the crosschain transfer. Should match the xcall's transfer ID in order for reconciliation to occur.
bumpTransfer (native asset)
Anyone can call this function on the origin domain to increase the relayer fee for a transfer. MUST be called on the origin domain.
Parameters
_transferId
bytes32
- The unique identifier of the crosschain transaction
bumpTransfer (transacting asset)
Anyone can call this function to increase the relayer fee for a transfer (using the _relayerFeeAsset specified). MUST be called on the origin domain.
Parameters
_transferId
bytes32
- The unique identifier of the crosschain transaction
_relayerfeeAsset
address
- The asset you are bumping fee with
_relayerFee
uint256
- The amount you want to bump transfer fee with
forceUpdateSlippage
Allows a user-specified account (delegate in xcall) to update the slippage they are willing to take on destination transfers. MUST be called on the destination chain.
Parameters
_params
struct TransferInfo
TransferInfo associated with the transfer
_slippage
uint256
The updated slippage
Interfaces
xReceive
Interface that the Connext contracts call into on the _to address specified during xcall. Developers MUST implement this on the destination chain to receive incoming calldata.
Parameters
_transferId
bytes32
Unique id of the xchain transaction
_amount
uint256
Amount of token, if any, passed into the contract in Wei units
_asset
address
Address of token, if any, passed into the contract
_originSender
address
Address of the contract or EOA that called xcall on the origin chain. NOTE: this param will only be populated if the transaction went through the slow path rather than being executed immediately by a Connext router (see TODO for details)
_origin
uint32
Domain ID of the chain that the transaction is coming from
_calldata
bytes
Data, in bytes, that is passed into xcall on the origin chain
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