Event signature · Stablecoins and issued tokens

AddedBlackList (USDT) event signature and topic0

The topic0 of the AddedBlackList (USDT) event is 0x42e160154868087d6bfdc0ca23d96a1c1cfa32f1b72ba9ba27b69b98a0d819dc, the keccak-256 hash of AddedBlackList(address); none of its arguments are indexed. Address frozen by the token issuer (Tether).

Anatomy of a AddedBlackList (USDT) log

Topics

topic00x42e160154868087d6bfdc0ca23d96a1c1cfa32f1b72ba9ba27b69b98a0d819dckeccak256("AddedBlackList(address)")

Data

data_user (address)ABI-encoded, decoded with the ABI

Parameters

Arguments and where they sit in the log

Indexed arguments travel as topics and can be filtered cheaply; the others are ABI-encoded together in the data.

Name	Type	In the log
_user	address	data

Solidity declaration

event AddedBlackList(address _user);

Canonical signature

AddedBlackList(address)

topic0

0x42e160154868087d6bfdc0ca23d96a1c1cfa32f1b72ba9ba27b69b98a0d819dc

Ready-made alerts

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Who emits it

Contracts we list that emit AddedBlackList

Any other contract with the same signature emits a log with the same topic0.

Tether (USDT)

0xdac17f958d2ee523a2206206994597c13d831ec7

Tracker: USDT (Tether)

Code

Read AddedBlackList logs in code

The same filter in viem, ethers and plain JSON-RPC, and the Solidity that emits it. The address is Tether (USDT), a contract we list that emits it.

viem

import { createPublicClient, http, parseAbiItem } from "viem"
import { mainnet } from "viem/chains"

const client = createPublicClient({ chain: mainnet, transport: http() })

const logs = await client.getLogs({
  address: "0xdac17f958d2ee523a2206206994597c13d831ec7",
  event: parseAbiItem("event AddedBlackList(address _user)"),
  fromBlock: "latest",
})

for (const log of logs) console.log(log.args) // { _user }

ethers v6

import { Interface, JsonRpcProvider } from "ethers"

const provider = new JsonRpcProvider(process.env.RPC_URL)
const iface = new Interface(["event AddedBlackList(address _user)"])

const logs = await provider.getLogs({
  address: "0xdac17f958d2ee523a2206206994597c13d831ec7",
  topics: [iface.getEvent("AddedBlackList")!.topicHash],
})

for (const log of logs) console.log(iface.parseLog(log)?.args)

JSON-RPC (eth_getLogs)

{
  "jsonrpc": "2.0",
  "id": 1,
  "method": "eth_getLogs",
  "params": [
    {
      "address": "0xdac17f958d2ee523a2206206994597c13d831ec7",
      "topics": [
        "0x42e160154868087d6bfdc0ca23d96a1c1cfa32f1b72ba9ba27b69b98a0d819dc"
      ],
      "fromBlock": "latest"
    }
  ]
}

Solidity

event AddedBlackList(address _user);

// inside a function:
emit AddedBlackList(_user);

Example

An example AddedBlackList log, encoded and decoded

Placeholder values, not a real transaction: how each argument is stored in the topics and the data, and what decoding gives back.

Encoded (as the node returns it)

topic0keccak256("AddedBlackList(address)")0x42e160154868087d6bfdc0ca23d96a1c1cfa32f1b72ba9ba27b69b98a0d819dc
data0x0000000000000000000000001111111111111111111111111111111111111111

Decoded with the ABI

_useraddress0x1111111111111111111111111111111111111111

FAQ

Frequently asked questions

What is the topic0 of the AddedBlackList (USDT) event?

0x42e160154868087d6bfdc0ca23d96a1c1cfa32f1b72ba9ba27b69b98a0d819dc: the keccak-256 hash of AddedBlackList(address).

Which AddedBlackList (USDT) arguments are indexed?

None: _user is ABI-encoded in the log's data, so a log can only be filtered by address and topic0.

How do I get an alert when a contract emits AddedBlackList (USDT)?

Open one of the ready-made rules on this page, or add any contract and pick AddedBlackList (USDT) from the event list. Conditions can be set on its arguments, and each alert names the contract and links to the transaction.

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