Bitcoin Address Monitor & Whale Alert — New Transactions

Watch any set of Bitcoin addresses and get told the moment they move funds. Each run reads the public blockchain (keyless) and, because it remembers what it saw last time, reports only the NEW transactions since the previous run — optionally only large "whale" moves, or only one direction. Schedule it + set a webhook and it becomes a standing alarm. Read-only, public ledger only — agent-callable.

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

What it does

• Reads each watched address's recent transactions from a keyless explorer (Blockstream Esplora, mempool.space fallback).
• Diffs against the previous run (state persisted in a named key-value store, stable per watch) and surfaces only what's new.
• Classifies each new transaction: direction (in/out), value (BTC + sats), counterparties, confirmation/time.
• Optional whale filter (minValueBtc) and direction filter.
• First run records a silent baseline (no history spam); 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
balanceBtc	current balance
newTransactions[]	each new tx: direction, valueBtc, counterparties, time, txid
newCount / largestMoveBtc	how many new + the biggest move

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 can tell new from already-seen across days of scheduled runs, and fire a webhook exactly when a wallet moves — a standing monitor an agent can't be, plus the deterministic diff/filtering at scale.

Input

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

Example input

{
  "addresses": ["1A1zP1eP5QGefi2DMPTfTL5SLmv7DivfNa"],
  "minValueBtc": 10,
  "direction": "both"
}

Output

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

{
  "address": "1A1zP1eP5QGefi2DMPTfTL5SLmv7DivfNa",
  "signal": "new-activity",
  "balanceBtc": 57.66512665,
  "newCount": 2,
  "largestMoveBtc": 0.5,
  "newTransactions": [
    {"txid": "c99e446ab2d4...", "direction": "in", "valueBtc": 0.5, "counterparties": ["bc1q..."], "confirmed": true, "time": "2026-10-17T01:40:00+00:00"}
  ]
}

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

Use cases

• Whale watching — alert when a known large wallet moves ≥ N BTC.
• Your own treasury — get pinged the moment funds leave or arrive at a company wallet.
• Investigations — standing watch on an address of interest.
• AI agents — a scheduled change-trigger: the agent acts only when the wallet moves.

Alerts / scheduling

1. Set addresses (+ optional minValueBtc / direction) and webhookUrl.
2. Schedule the actor (e.g. every 10 min or hourly) in Apify.
3. The first run is a silent baseline; after that, each run that finds new transactions POSTs them to your webhook (Slack/Discord/email via Make/Zapier).

Ready-made tasks

• Bitcoin Whale Alert - Large Transfers from Watched Wallets

For AI agents / MCP

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

Loads as centorprat--bitcoin-address-monitor-whale-alert. Claude Code:

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

FAQ

Which chain? Bitcoin mainnet (bech32 bc1… and base58 1…/3…).

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

How does it know what's new? It stores the transaction 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 transaction at or above your minValueBtc (or ≥ 50 BTC if you leave the threshold at 0).

Will the first run spam me with history? No — the first run is a silent baseline.

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

Is it legal? It reads the public Bitcoin ledger only. Alerts are factual on-chain events, never accusations about who owns an address or why funds moved.

Data & attribution

Public Bitcoin blockchain via the keyless Blockstream Esplora API (mempool.space fallback). No keys, no personal data. Signals, not advice.

Related actors

• Bitcoin Wallet & Transaction Tracer
• Crypto Address Risk & AML Screener