Onchain Data

Onchain activity detected

Triggered when onchain activity matching your subscription filters is detected. Your API will receive a POST request at the webhook URL you configured. Use labels on your webhook subscription to filter which onchain events are delivered (see the Create Webhook Subscription endpoint for allowed labels).

postWebhookonchainActivityDetected

Payload

block_numberinteger required

The block number containing the transaction that emitted the event.

contract_addressstring required

The contract address that emitted the event.

event_namestring required

The name of the decoded contract event.

event_signaturestring required

The canonical event signature used to decode the log, including parameter types (e.g., Transfer(address,address,uint256)).

log_indexinteger required

The zero-based index of the log within the transaction.

networkstring required

The blockchain network where the activity was detected.

parametersOnchainActivityEventParameters required

Decoded event parameters from the contract event. Keys correspond to the named arguments in the event signature (e.g., from, to, value for an ERC-20 Transfer). Values are returned as strings to preserve precision for large integers and to avoid loss for address types. The exact set of keys depends on the contract event.

timestampstring date-time required

The block timestamp of the transaction (ISO 8601 format).

transaction_fromstring required

The address that initiated the transaction (the transaction sender).

transaction_hashstring required

The hash of the transaction that emitted the event.

transaction_tostring required

The address the transaction was sent to (typically a contract address).

Example payload

{
  "block_number": 46218191,
  "contract_address": "0x940181a94A35A4569E4529A3CDfB74e38FD98631",
  "event_name": "Transfer",
  "event_signature": "Transfer(address,address,uint256)",
  "log_index": 29,
  "network": "base-mainnet",
  "parameters": {
    "from": "0xF33a96b5932D9E9B9A0eDA447AbD8C9d48d2e0c8",
    "to": "0x61040E143A77F165Ba44543AF4A079F2C809D14b",
    "value": "474891138228179365"
  },
  "timestamp": "2026-05-19T21:22:10Z",
  "transaction_from": "0x3E16D476D8Df15e3E776EAa5A46f37EC44C830cD",
  "transaction_hash": "0xa58e4471bcce875b1ea49cc0864a620d3a484b9b7c1b0b4fd18ce83f5b30e5e0",
  "transaction_to": "0x61040E143A77F165Ba44543AF4A079F2C809D14b"
}

Response

Webhook received and processed successfully. Return a 200 status code to acknowledge receipt. If your endpoint does not return a 2xx status code, the webhook will be retried with exponential backoff.

Changes

Webhooks have no change history: a webhook is keyed by its event name rather than a path and method, so no recorded change can name it.