LOG

Supported Network

Network	Supporting
Ethereum Mainnet	✅
Ethereum Testnet (sepolia)	✅
Ethereum Testnet (hoodi)	✅
Base Mainnet	✅
Base Testnet (sepolia)	✅
Polygon Mainnet	✅
Arbitrum Mainnet	✅
Arbitrum Testnet (sepolia)	✅
Optimism Mainnet	✅
Optimism Testnet (sepolia)	✅
Kaia Mainnet	✅
Kaia Testnet (kairos)	✅
Tron Mainnet	✅
Arc Mainnet	✅
Arc Testnet	✅
Aptos Mainnet	❌
Aptos Testnet	❌

Conditions

When eventType is set to LOG, the available condition object fields are listed below.

Key	Type	Description	Required	Example Value
address	String	Contract address where the event to monitor is defined.	true	0xdAC17F958D2ee523a2206206994597C13D831ec7
topics[4]	Array of String	Topic array object for the event log to monitor. Can contain up to 4 strings.	true	["0xddf252ad1be2c89b69c2b068fc378daa952ba7f163c4a11628f55a4df523b3ef", "0x000000000000000000000000b7aa2d3c833a6827c4f39bef9622d7cddf66b7e7", "0x0000000000000000000000003264039cfaa37a70a0e8ccfbf4b7e60bedce5c9f"]

ℹ️I have an event log I want to monitor. What value should I put in the Topic field?

The Topic field for the event you want to monitor is used to filter data associated with smart contract events. Each topic contains the event signature and indexed parameter information for the event.

topics[0]: Event Signature

topics[0] is always the Keccak256 hash of the event signature.
For example, for the Transfer(address indexed from, address indexed to, uint256 value) event, the event signature can be obtained by running the following:
Keccak256("Transfer(address,address,uint256)")
= 0xddf252ad1be2c89b69c2b068fc378daa952ba7f163c4a11628f55a4df523b3ef

topics[1], topics[2], topics[3]: Indexed Parameters

Starting from topics[1], each entry corresponds to an indexed parameter value of the event. Only event parameters declared with the indexed keyword in the smart contract are included in the topics. For the Transfer event above, the from address corresponds to topics[1] and the to address corresponds to topics[2]. To filter only events where a specific address appears as the from address, enter that address value in topics[1]. The remaining non-indexed parameters can be found in the data field of the retrieved log.

How to find Topic values

From the smart contract code: Identify the event definition in the Solidity code, locate the indexed parameters and event signature, then compute the topic value using Keccak256 hashing.
Using a block explorer: Select a sample transaction to trace, navigate to the transaction detail, and find the topic values in the "Logs" section. Below is an example screen from Etherscan (https://etherscan.io) showing the log for a USDC (ERC20) Transfer event.

Response Example

📍 Type: Log (EVM)

Event logs emitted on EVM-based chains.

subscription_connected The user(8350954814192461336) is connected. 
registered messageId: 123,
subscriptionId: 5096
subscription Event :  subscriptionId: 5096,
  eventType: LOG,
  event: {
  "targetAddresses": [
    "0xdAC17F958D2ee523a2206206994597C13D831ec7"
  ],
  "topics": [
    "0xddf252ad1be2c89b69c2b068fc378daa952ba7f163c4a11628f55a4df523b3ef"
  ],
  "messages": [
    {
      "address": "0xdac17f958d2ee523a2206206994597c13d831ec7",
      "topics": [
        "0xddf252ad1be2c89b69c2b068fc378daa952ba7f163c4a11628f55a4df523b3ef",
        "0x0000000000000000000000009696f59e4d72e237be84ffd425dcad154bf96976",
        "0x000000000000000000000000586197da4971fadf8604b8fd81f2a576032402d2"
      ],
      "data": "0x0000000000000000000000000000000000000000000000000000009e52bdc040",
      "block_number": 21570934,
      "transaction_hash": "0x905de51ac1f611942343d1a4b9b913bd392b5b3bcb100f22167ef2670a36df18",
      "transaction_index": 10,
      "log_index": 22,
      "block_hash": "0xc3f7d16da3dd3649e20dfec4346b2a967f9ff369b770d1e1f979fbe58e77e8ce",
      "block_timestamp": 1736232887,
      "removed": false,
      "type": "log"
    }
  ]
}

📍 Type: Log (Tron)

Event logs emitted on the Tron chain. Addresses are provided in Base58 format (starting with T), and topics and data are hex strings without the 0x prefix. Unlike EVM logs, there is no removed field, and tx_id/tx_index are used instead of transaction_hash/transaction_index.

subscription_connected The user(8350954814192461336) is connected.
registered messageId: 123,
subscriptionId: 5097
subscription Event : subscriptionId: 5097,
eventType: LOG,
event: {
  "targetAddresses": [
    "T..."
  ],
  "topics": [
    "ddf252ad..."
  ],
  "messages": [
    {
      "address": "T...",
      "topics": [
        "ddf252ad..."
      ],
      "data": "0000...",
      "log_index": 0,
      "tx_id": "...",
      "tx_index": 323,
      "block_number": 85768711,
      "block_timestamp": 1787978412,
      "block_hash": "00000000051cba07...",
      "type": "log"
    }
  ]
}