# Call EVM Function

The Call EVM Function task allows you to obtain any on-chain data to your midpoint by doing a direct RPC call to an on-chain view function. This task is used in a wide variety of workflows, such as cross-chain data bridging and retrieving values from any other chain back onto the chain your application lives on.

## **Definition**

```graphql
chainId: string # required
contractAddress: string # required
functionName: string # required
arguments: [
    {
        name: string
        datatype: string
        value: string
    }
]
returnValues: [ # at least one value is required
    {
        name: string
        datatype: string
    }
]
extracts: [
    {
        name: string
        from: string
    }
]
excludeLogs: [string]
```

**`chainId`: String.** The Chain ID of the chain to request data from. For a complete list of Chain Ids that we currently support, take a look at [chain-ids](https://docs.midpointapi.com/midpoint-documentation/more-reading/chain-ids "mention").

**`contractAddress`: String.** The address of the contract that Call EVM Function calls. This contract address should exist on the chain you are calling.

**`functionName`: String.** This is name of the function you are calling from the Call EVM Function task. 

**`arguments`:** This specifies both the signature of your on-chain function, and any values that are going to be submitted by the Call EVM Function task.

**`arguments.name`: String.** This is the name of the argument that you are passing in. This is a human-readable name that you set: for clarity, it might be best to set this name to the name of the parameter you are calling. 

**`arguments.datatype`: String.** This defines the solidity datatype of the value that is passed into the on-chain function. This datatype must match the datatype of your on-chain function exactly, in the same order as they are defined in the on-chain function.

**`arguments.from`: String.** This defines the value that will be submitted on-chain when your Call EVM Function does a call. If you directly put in a value, it will be a constant that is always submitted. We recommend entering a variable name that will be interpolated during runtime after it is extracted from a previous source or task.

**`returnValues`: String**This specifies the return values that will be returned after you call your EVM function. These values will be automatically extracted as a variable to be used by downstream tasks.

**`returnValues.name`: String.** This is the name of the argument that is being returned in. This is a human-readable name that you set, which will be the name of the variable that is generated.

**`returnValues.datatype`: String.** This defines the solidity datatype of the value that is returned by the on-chain function. This datatype must match the datatype of your on-chain function's return values exactly, in the same order as they are defined in the on-chain function.

**`extracts`: See** [**extracts**](https://docs.midpointapi.com/midpoint-documentation/core-concepts/midpoints/source-and-task-definitions/extracts)**.** Legal values:

* **`Timestamp`** Unixtime of execution.

**`excludeLogs`: See** [**exclude logs**](https://docs.midpointapi.com/midpoint-documentation/core-concepts/midpoints/source-and-task-definitions/exclude-logs)**.** Legal values:

* **`TaskDefinition`** The complete definition of this task at runtime.
* **`TaskOutputData`** The complete set of returned values from this task.

## Returned Values

This task returns any values extracted using the `extracts` which are outlined above. Additionally, this task returns any values defined in returnValues, where the name of the variable created is the name specified by the user.

## Examples

This section is incomplete.

## Tips for Using Call Evm Function

* Use a variable from a source or a previous task for the value of an argument. This makes the values that you submit back on-chain dynamic.
* Use your [midpoint-id](https://docs.midpointapi.com/midpoint-documentation/core-concepts/midpoints/midpoint-id "mention") as your first argument to ensure your smart contracts [security](https://docs.midpointapi.com/midpoint-documentation/tasks/transact-to-evm-function/security "mention").
* Use a variable for your chainId, and have it originate from on-chain. If you use the implicit **Chain\_ID** from your [startpoint-called](https://docs.midpointapi.com/midpoint-documentation/sources/startpoint-called "mention")source, you can have a chain-agnostic data bridge that uses the same midpoint.