> For the complete Linea documentation index, see [llms.txt](/llms.txt). > Agents can fetch this page as Markdown at [https://docs.linea.build/api/linea-smart-contracts/interfaces/imessageservice.md](https://docs.linea.build/api/linea-smart-contracts/interfaces/imessageservice.md). # IMessageService # `IMessageService` ### MessageSent ```solidity event MessageSent(address _from, address _to, uint256 _fee, uint256 _value, uint256 _nonce, bytes _calldata, bytes32 _messageHash) ``` Emitted when a message is sent. #### Parameters | Name | Type | Description | | --- | --- | --- | | _from | address | The indexed sender address of the message (msg.sender). | | _to | address | The indexed intended recipient address of the message on the other layer. | | _fee | uint256 | The fee being being paid to deliver the message to the recipient in Wei. | | _value | uint256 | The value being sent to the recipient in Wei. | | _nonce | uint256 | The unique message number. | | _calldata | bytes | The calldata being passed to the intended recipient when being called on claiming. | | _messageHash | bytes32 | The indexed hash of the message parameters. | ### MessageClaimed ```solidity event MessageClaimed(bytes32 _messageHash) ``` Emitted when a message is claimed. #### Parameters | Name | Type | Description | | --- | --- | --- | | _messageHash | bytes32 | The indexed hash of the message that was claimed. | ### FeeTooLow ```solidity error FeeTooLow() ``` _Thrown when fees are lower than the minimum fee._ ### ValueSentTooLow ```solidity error ValueSentTooLow() ``` ### MessageSendingFailed ```solidity error MessageSendingFailed(address destination) ``` _Thrown when the destination address reverts._ ### FeePaymentFailed ```solidity error FeePaymentFailed(address recipient) ``` _Thrown when the recipient address reverts._ ### sendMessage ```solidity function sendMessage(address _to, uint256 _fee, bytes _calldata) external payable ``` Sends a message for transporting from the given chain. #### Parameters | Name | Type | Description | | --- | --- | --- | | _to | address | The destination address on the destination chain. | | _fee | uint256 | The message service fee on the origin chain. | | _calldata | bytes | The calldata used by the destination message service to call the destination contract. | ### claimMessage ```solidity function claimMessage(address _from, address _to, uint256 _fee, uint256 _value, address payable _feeRecipient, bytes _calldata, uint256 _nonce) external ``` Deliver a message to the destination chain. Is called by the Postman, dApp or end user. #### Parameters | Name | Type | Description | | --- | --- | --- | | _from | address | The msg.sender calling the origin message service. | | _to | address | The destination address on the destination chain. | | _fee | uint256 | The message service fee on the origin chain. | | _value | uint256 | The value to be transferred to the destination address. | | _feeRecipient | address payable | Address that will receive the fees. | | _calldata | bytes | The calldata used by the destination message service to call/forward to the destination contract. | | _nonce | uint256 | Unique message number. | ### sender ```solidity function sender() external view returns (address originalSender) ``` Returns the original sender of the message on the origin layer. #### Return Values | Name | Type | Description | | --- | --- | --- | | originalSender | address | The original sender of the message on the origin layer. | Contributions not accepted These reference pages are automatically generated based on Linea's [smart contracts](https://github.com/Consensys/linea-monorepo/tree/main/contracts/src). To ensure they accurately match the deployed smart contracts, we cannot accept any contributions that edit these pages.