Ethereum Address Monitor & Alert — New Transactions & Tokens

Watch any set of Ethereum addresses and get told the moment they move. Each run reads the public chain (keyless) for recent ETH transactions and ERC-20 token transfers and, because it remembers what it saw last time, reports only the NEW events since the previous run — optionally only large USD moves, or one direction. Schedule it + set a webhook and it becomes a standing alarm. Read-only, public chain only — agent-callable.

For on-chain analysts, treasury/ops watching company wallets, researchers tracking known addresses, and AI agents that need a change-trigger on an Ethereum wallet.

What it does

• Reads each watched address's recent ETH transactions and token transfers via the keyless Ethplorer API.
• Diffs against the previous run (state in a named key-value store, stable per watch) and surfaces only what's new.
• Values each event in USD, classifies direction (in/out) and counterparty, and filters out spam-token noise.
• Optional whale filter (minValueUsd) and direction filter.
• First run records a silent baseline; later runs report (and with a webhook, alert) only on new activity.

Output field	Meaning
signal	baseline-established / new-activity / whale-move / no-new-matching-activity
balanceEth	current ETH balance
newEvents[]	each new event: kind (eth/token), asset, amount, usdValue, direction, counterparty, time, txHash
newCount / largestMoveUsd	how many new + the biggest move in USD

Why not just ask an AI agent?

An agent has no memory between runs and no scheduler. This actor keeps durable state per watch, so it distinguishes new from already-seen across days of scheduled runs and fires a webhook exactly when a wallet moves — covering both ETH and token transfers, valued and de-spammed. A standing monitor an agent can't be.

Input

Field	Type	Required	Description
addresses	array of strings	✅	Ethereum addresses to watch.
minValueUsd	integer		Only alert on moves ≥ this many USD (0 = all).
direction	string		both / in / out.
webhookUrl	string		POST new events here when found.

Example input

{
  "addresses": ["0xd8dA6BF26964aF9D7eEd9e03E53415D37aA96045"],
  "minValueUsd": 100000,
  "direction": "both"
}

Output

One record per watched address. Example (a run that found new activity):

{
  "address": "0xd8dA6BF26964aF9D7eEd9e03E53415D37aA96045",
  "signal": "new-activity",
  "balanceEth": 5.7697,
  "newCount": 2,
  "largestMoveUsd": 125000.0,
  "newEvents": [
    {"kind": "token", "asset": "USDC", "amount": 125000.0, "usdValue": 125000.0, "direction": "in", "counterparty": "0x...", "txHash": "0x...", "time": "2026-10-17T01:20:00+00:00"}
  ]
}

The first run instead returns signal: "baseline-established" and alerts on nothing.

Use cases

• Whale watching — alert when a known wallet moves ≥ $N in ETH or tokens.
• Treasury / ops — get pinged the moment funds leave or arrive at a company wallet.
• Investigations — standing watch on an address of interest (ETH + tokens).
• AI agents — a scheduled change-trigger that acts only when the wallet moves.

Alerts / scheduling

1. Set addresses (+ optional minValueUsd / direction) and webhookUrl.
2. Schedule the actor in Apify (e.g. every 10–30 min).
3. First run = silent baseline; after that, runs that find new events POST them to your webhook (Slack/Discord/email via Make/Zapier).

Ready-made tasks

• Ethereum Whale Alert - Large Transfers from Watched Wallets

For AI agents / MCP

https://mcp.apify.com/?tools=actors,docs,centorprat/ethereum-address-monitor-alert

Loads as centorprat--ethereum-address-monitor-alert. Claude Code:

claude mcp add apify -- npx -y @apify/actors-mcp-server --actors centorprat/ethereum-address-monitor-alert

FAQ

Which chain? Ethereum mainnet — both native ETH transactions and ERC-20 token transfers.

Does it need a key? No — keyless public API.

How does it know what's new? It stores the event ids it has seen (per watch) in a named key-value store, so it survives between scheduled runs and diffs against them.

What's a "whale-move"? A new event at or above your minValueUsd (or ≥ $100k if you leave the threshold at 0).

Does it spam me with spam tokens? No — scam/airdrop token transfers are filtered; only real tokens (priced or well-held) count.

Cost? Pay-per-event: a small base per run + a premium per new event alerted — quiet runs cost only the base.

Is it legal? It reads the public Ethereum ledger only. Alerts are factual on-chain events, never accusations.

Data & attribution

Public Ethereum chain data via the keyless Ethplorer API; USD values are indicative. No keys, no personal data. Signals, not advice.

Related actors

• Crypto Address Risk & AML Screener
• Ethereum Wallet & Token Tracer
• Bitcoin Address Monitor & Whale Alert