> 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/messageservice/l1/v1/l1messageservicev1.md](https://docs.linea.build/api/linea-smart-contracts/messageservice/l1/v1/l1messageservicev1.md). # L1MessageServiceV1 # `L1MessageServiceV1` ### nextMessageNumber ```solidity uint256 nextMessageNumber ``` ### _messageSender ```solidity address _messageSender ``` _DEPRECATED in favor of new transient storage with `MESSAGE_SENDER_TRANSIENT_KEY` key._ ### REFUND_OVERHEAD_IN_GAS ```solidity uint256 REFUND_OVERHEAD_IN_GAS ``` _adding these should not affect storage as they are constants and are stored in bytecode._ ### MESSAGE_SENDER_TRANSIENT_KEY ```solidity bytes32 MESSAGE_SENDER_TRANSIENT_KEY ``` _The transient storage key to set the message sender against while claiming._ ### DEFAULT_MESSAGE_SENDER_TRANSIENT_VALUE ```solidity address DEFAULT_MESSAGE_SENDER_TRANSIENT_VALUE ``` The default value for the message sender reset to post claiming using the MESSAGE_SENDER_TRANSIENT_KEY. ### distributeFees ```solidity modifier distributeFees(uint256 _feeInWei, address _to, bytes _calldata, address _feeRecipient) ``` The unspent fee is refunded if applicable. #### Parameters | Name | Type | Description | | --- | --- | --- | | _feeInWei | uint256 | The fee paid for delivery in Wei. | | _to | address | The recipient of the message and gas refund. | | _calldata | bytes | The calldata of the message. | | _feeRecipient | address | | ### claimMessage ```solidity function claimMessage(address _from, address _to, uint256 _fee, uint256 _value, address payable _feeRecipient, bytes _calldata, uint256 _nonce) external ``` Claims and delivers a cross-chain message. #### Parameters | Name | Type | Description | | --- | --- | --- | | _from | address | The address of the original sender. | | _to | address | The address the message is intended for. | | _fee | uint256 | The fee being paid for the message delivery. | | _value | uint256 | The value to be transferred to the destination address. | | _feeRecipient | address payable | The recipient for the fee. | | _calldata | bytes | The calldata to pass to the recipient. | | _nonce | uint256 | The unique auto generated nonce used when sending the message. | 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.