# CCIP v1.5.0 Client Library API Reference Source: https://docs.chain.link/ccip/api-reference/evm/v1.5.0/client CCIP senders and receivers use the CCIP [`Client`](https://github.com/smartcontractkit/ccip/tree/release/contracts-ccip-1.5.0/contracts/src/v0.8/ccip/libraries/Client.sol) library to build CCIP messages. ```solidity import { Client } from "@chainlink/contracts-ccip/src/v0.8/ccip/libraries/Client.sol"; ``` ## Types and Constants ### EVMTokenAmount Use this solidity struct to specify the token address and amount. ```solidity struct EVMTokenAmount { address token; uint256 amount; } ``` | Name | Type | Description | | ------ | ------- | --------------------------------- | | token | address | token address on the local chain. | | amount | uint256 | Amount of tokens. | ### Any2EVMMessage CCIP receivers use this solidity struct to parse the received CCIP message. ```solidity struct Any2EVMMessage { bytes32 messageId; uint64 sourceChainSelector; bytes sender; bytes data; struct Client.EVMTokenAmount[] destTokenAmounts; } ``` | Name | Type | Description | | ------------------- | ------------------------ | ------------------------------------------------------------------------------------ | | messageId | bytes32 | CCIP messageId, generated on the source chain. | | sourceChainSelector | uint64 | Source chain selector. | | sender | bytes | Sender address. `abi.decode(sender, (address))` if the source chain is an EVM chain. | | data | bytes | Payload sent within the CCIP message. | | destTokenAmounts | Client.EVMTokenAmount\[] | Tokens and their amounts in their destination chain representation. | ### EVM2AnyMessage CCIP senders use this solidity struct to build the CCIP message. ```solidity struct EVM2AnyMessage { bytes receiver; bytes data; struct Client.EVMTokenAmount[] tokenAmounts; address feeToken; bytes extraArgs; } ``` | Name | Type | Description | | ------------ | ------------------------ | -------------------------------------------------------------------------------------------------------------------------------- | | receiver | bytes | Receiver address. Use `abi.encode(sender)` to encode the address to *bytes*. | | data | bytes | Payload sent within the CCIP message. | | tokenAmounts | Client.EVMTokenAmount\[] | Tokens and their amounts in the source chain representation. | | feeToken | address | Address of feeToken. Set `address(0)` to pay in native gas tokens such as ETH on Ethereum or POL on Polygon. | | extraArgs | bytes | Users fill in the [EVMExtraArgs struct](#evmextraargs) then encode it to bytes using the [\_argsToBytes function](#_argstobytes) | ### EVM\_EXTRA\_ARGS\_TAG #### EVM\_EXTRA\_ARGS\_V1\_TAG > **NOTE** > > This version (v1) is maintained for backward compatibility. You can already switch to v2. ```solidity bytes4 EVM_EXTRA_ARGS_V1_TAG ``` #### EVM\_EXTRA\_ARGS\_V2\_TAG ```solidity bytes4 EVM_EXTRA_ARGS_V2_TAG ``` ### EVMExtraArgs #### EVMExtraArgsV1 > **NOTE** > > This version (v1) is maintained for backward compatibility. You can already switch to v2. ```solidity struct EVMExtraArgsV1 { uint256 gasLimit; } ``` | Name | Type | Description | | -------- | ------- | ------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------ | | gasLimit | uint256 | specifies the maximum amount of gas CCIP can consume to execute `ccipReceive()` on the contract located on the destination blockchain. Read [Setting gasLimit](/ccip/concepts/best-practices/evm#setting-gaslimit) for more details. | #### EVMExtraArgsV2 ```solidity struct EVMExtraArgsV2 { uint256 gasLimit; bool allowOutOfOrderExecution; } ``` | Name | Type | Description | | ------------------------ | ------- | ------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- | | gasLimit | uint256 | specifies the maximum amount of gas CCIP can consume to execute `ccipReceive()` on the contract located on the destination blockchain. Read [Setting gasLimit](/ccip/concepts/best-practices/evm#setting-gaslimit) for more details. | | allowOutOfOrderExecution | bool | if true, it indicates that the message can be executed in any order relative to other messages from the same sender. This value's default varies by chain. On some chains, a particular value is enforced, meaning if the expected value is not set, the message request will revert. | ## Functions ### \_argsToBytes #### \_argsToBytes (v1) > **NOTE** > > This version (v1) is maintained for backward compatibility. You can already switch to v2. ```solidity function _argsToBytes(struct Client.EVMExtraArgsV1 extraArgs) internal pure returns (bytes bts) ``` It is used to convert the arguments to bytes. ##### Parameters | Name | Type | Description | | --------- | ---------------------------------------- | ---------------- | | extraArgs | [Client.EVMExtraArgsV1](#evmextraargsv1) | Extra arguments. | ##### Return Values | Name | Type | Description | | ---- | ----- | ----------------------------------- | | bts | bytes | Encoded extra arguments in *bytes*. | #### \_argsToBytes (v2) ```solidity function _argsToBytes(struct Client.EVMExtraArgsV2 extraArgs) internal pure returns (bytes bts) ``` It is used to convert the arguments to bytes. ##### Parameters | Name | Type | Description | | --------- | ---------------------------------------- | ---------------- | | extraArgs | [Client.EVMExtraArgsV2](#evmextraargsv2) | Extra arguments. | ##### Return Values | Name | Type | Description | | ---- | ----- | ----------------------------------- | | bts | bytes | Encoded extra arguments in *bytes*. |