Smart Contract Write
Execute a state-changing function on any smart contract. Provide the contract ABI and function name; the transaction is signed and broadcast from your connected wallet. Use for: staking, governance votes, custom contract interactions.
Catalog action EVM Onchain wallet Gas send
Execute a state-changing function on any smart contract. Provide the contract ABI and function name; the transaction is signed and broadcast from your connected wallet. Use for: staking, governance votes, custom contract interactions.
This action can require a wallet connector, gas, token movement, or an external side effect. Test with simulation or a controlled amount before using it in a live workflow.
At a Glance
| Field | Value |
|---|---|
| Action ID | evm-write |
| Category | EVM Onchain |
| Connector | wallet |
| Requires gas | Yes |
| Funds movement | send |
| Tags | blockchain, evm, write, contract, transaction, execute, custom, abi, defi |
Payload Schema
| Field | Type | Required | Description |
|---|---|---|---|
contractProjectId | string | No | Select a deployed contract project or choose 'Custom' to enter address and ABI manually. |
chainId | number | Yes | Chain ID (1=Ethereum, 137=Polygon, 56=BSC, 8453=Base, etc.) |
contractAddress | string | No | The contract address to interact with |
abi | string | No | The ABI of the contract function(s) as a JSON string array. Can be full contract ABI or just the function signature needed. |
functionName | string | Yes | The name of the function to call |
args | object | No | Arguments for the function call as a JSON string array (e.g., '["0x123...", "1000"]') or a native array. Optional if function has no arguments. |
value | string | No | Amount of native token (ETH, MATIC, etc.) to send with the transaction in Wei. Optional, defaults to '0'. |
gasLimit | string | No | Optional gas limit for the transaction. If not provided, will be estimated. |
maxFeePerGas | string | No | Optional max fee per gas in Wei (EIP-1559). If not provided, will be estimated. |
maxPriorityFeePerGas | string | No | Optional max priority fee per gas in Wei (EIP-1559). If not provided, will be estimated. |
waitForConfirmation | boolean | No | Whether to wait for transaction confirmation. Defaults to true. |
confirmations | number | No | Number of confirmations to wait for. Defaults to 1. |
Result Schema
| Field | Type | Required | Description |
|---|---|---|---|
status | string | Yes | - |
transactionHash | string | Yes | The transaction hash |
blockNumber | number | No | The block number where transaction was mined |
gasUsed | string | No | Gas used by the transaction |
from | string | No | The sender address (Turnkey wallet) |
effectiveGasPrice | string | No | The effective gas price used |
Examples
json{ "type": "evm-write", "payload": { "functionName": "example-functionName", "chainId": 8453 }, "children": [], "connector": { "type": "wallet", "id": "conn_wallet" }}
bashcurl -X POST "https://api.b3os.org/v1/actions/evm-write/test" \ -H "Authorization: Bearer YOUR_API_KEY" \ -H "Content-Type: application/json" \ -d '{ "inputs": { "functionName": "example-functionName", "chainId": 8453 }}'
Payload fields can use workflow expressions such as {{$trigger.body.amount}}, {{$nodes.fetch.result.price}}, and {{$props.asset}} when the value should come from a trigger, prior node, or reusable workflow prop.