Event signature · Stablecoins and issued tokens

UnBlacklisted (USDC) event signature and topic0

The topic0 of the UnBlacklisted (USDC) event is 0x117e3210bb9aa7d9baff172026820255c6f6c30ba8999d1c2fd88e2848137c4e, the keccak-256 hash of UnBlacklisted(address); 1 of its 1 arguments is indexed. Address unfrozen by the token issuer (Circle FiatToken).

Anatomy of a UnBlacklisted (USDC) log

Topics

  • topic00x117e3210bb9aa7d9baff172026820255c6f6c30ba8999d1c2fd88e2848137c4ekeccak256("UnBlacklisted(address)")
  • topic1_account (address)indexed: filterable
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.

NameTypeIn the log
_accountaddresstopic1

Solidity declaration

event UnBlacklisted(address indexed _account);

Canonical signature

UnBlacklisted(address)

topic0

0x117e3210bb9aa7d9baff172026820255c6f6c30ba8999d1c2fd88e2848137c4e

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Who emits it

Contracts we list that emit UnBlacklisted

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

Code

Read UnBlacklisted logs in code

The same filter in viem, ethers and plain JSON-RPC, and the Solidity that emits it. The address is USD Coin (USDC), 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: "0xa0b86991c6218b36c1d19d4a2e9eb0ce3606eb48",
  event: parseAbiItem("event UnBlacklisted(address indexed _account)"),
  fromBlock: "latest",
})

for (const log of logs) console.log(log.args) // { _account }
ethers v6
import { Interface, JsonRpcProvider } from "ethers"

const provider = new JsonRpcProvider(process.env.RPC_URL)
const iface = new Interface(["event UnBlacklisted(address indexed _account)"])

const logs = await provider.getLogs({
  address: "0xa0b86991c6218b36c1d19d4a2e9eb0ce3606eb48",
  topics: [iface.getEvent("UnBlacklisted")!.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": "0xa0b86991c6218b36c1d19d4a2e9eb0ce3606eb48",
      "topics": [
        "0x117e3210bb9aa7d9baff172026820255c6f6c30ba8999d1c2fd88e2848137c4e"
      ],
      "fromBlock": "latest"
    }
  ]
}
Solidity
event UnBlacklisted(address indexed _account);

// inside a function:
emit UnBlacklisted(_account);
Example

An example UnBlacklisted 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("UnBlacklisted(address)")0x117e3210bb9aa7d9baff172026820255c6f6c30ba8999d1c2fd88e2848137c4e
  • topic1_account0x0000000000000000000000001111111111111111111111111111111111111111
  • data0x
Decoded with the ABI
  • _accountaddress · indexed0x1111111111111111111111111111111111111111
FAQ

Frequently asked questions

What is the topic0 of the UnBlacklisted (USDC) event?

0x117e3210bb9aa7d9baff172026820255c6f6c30ba8999d1c2fd88e2848137c4e: the keccak-256 hash of UnBlacklisted(address).

Which UnBlacklisted (USDC) arguments are indexed?

_account is indexed and sit in the log's topics.

How do I get an alert when a contract emits UnBlacklisted (USDC)?

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

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