eth_callAfter

eth_callAfter — execute eth_call after waiting for an account's nonce to reach a target value.

Executes eth_call after waiting for an account's nonce to reach a target value. Useful for simulating a transaction that depends on prior transactions completing — for example, checking the result of a swap after a preceding approval has been confirmed.

Parameters

Pass params as [request, condition, stateOverride, blockOverrides]. Only request and condition are required.

request

Describes the simulated transaction.

Field	Type	Required	Notes
to	Data (20 bytes)	Yes	Target contract address
from	Data (20 bytes)	No	Sender address. Set explicitly when msg.sender matters
input	Data	No	Calldata. MegaETH also accepts data, but prefer input for portability
value	Quantity	No	Wei to send with the call
gas	Quantity	No	Gas limit for the simulation
gasPrice	Quantity	No	Legacy gas price. Cannot be combined with EIP-1559 fee fields
maxFeePerGas	Quantity	No	EIP-1559 max fee. Cannot be combined with gasPrice
maxPriorityFeePerGas	Quantity	No	EIP-1559 priority fee. Cannot be combined with gasPrice

condition

Field	Type	Required	Notes
account	Data (20 bytes)	Yes	Account address whose nonce to monitor
nonce	Quantity	Yes	Target nonce value to wait for
timeout	Number	No	Max wait time in milliseconds. Default: 3000. Max: 60000

stateOverride

Optional. Temporary account-level overrides applied only for this simulation. Keyed by address.

Field	Type	Notes
balance	Quantity	Override the account balance
nonce	Quantity	Override the account nonce
code	Data	Override the account bytecode
state	Object	Replace the entire storage (slot → value). Cannot be combined with stateDiff
stateDiff	Object	Patch individual storage slots. Cannot be combined with state

blockOverrides

Optional. Temporary block-environment overrides applied only for this simulation.

Field	Type	Notes
number	Quantity	Override block.number
time	Quantity	Override block.timestamp
gasLimit	Quantity	Override block.gasLimit
feeRecipient	Data (20 bytes)	Override block.coinbase
baseFeePerGas	Quantity	Override block.baseFee

Returns

Field	Type	Notes
result	Data	Return data from the executed call — same as eth_call

Errors

Code	Cause	Fix
-32000	Timeout: timeout waiting for nonce condition — nonce did not reach the target within the timeout	Increase timeout, or verify the prior transaction was submitted
-32000	InternalError — internal processing error	Retry the request

See also Error reference.

Example

Execute eth_call after waiting for account nonce to reach 5:

curl -sS https://mainnet.megaeth.com/rpc \
  -X POST -H "Content-Type: application/json" \
  -d '{
    "jsonrpc": "2.0",
    "id": 1,
    "method": "eth_callAfter",
    "params": [
      {
        "from": "0xf39fd6e51aad88f6f4ce6ab8827279cfffb92266",
        "to": "0x1234567890abcdef1234567890abcdef12345678",
        "data": "0x70a08231000000000000000000000000f39fd6e51aad88f6f4ce6ab8827279cfffb92266"
      },
      {
        "account": "0xf39fd6e51aad88f6f4ce6ab8827279cfffb92266",
        "nonce": "0x5",
        "timeout": 30000
      }
    ]
  }'

Successful response:

{
  "jsonrpc": "2.0",
  "id": 1,
  "result": "0x0000000000000000000000000000000000000000000000000de0b6b3a7640000"
}

Timeout response:

{
  "jsonrpc": "2.0",
  "id": 1,
  "error": {
    "code": -32000,
    "message": "Timeout: timeout waiting for nonce condition"
  }
}