Introduction

Alchemy's Bitcoin Address Activity webhook notifies your app when a transaction in a new block spends from or pays to one of the addresses that you configure. Each notification gives the transaction from the point of view of your address: whether the address received or sent BTC, its net balance change, the fee, and every input and output of the transaction.

The webhook supports all standard address types: legacy (1...), P2SH (3...), and SegWit and Taproot (bc1...). It is available on Bitcoin Mainnet and Bitcoin Testnet4.

How activity is reported

Bitcoin uses unspent transaction outputs (UTXOs), not account balances. A transaction spends one or more earlier outputs (its inputs) and creates new outputs, so one transaction can involve many addresses. For this reason the webhook reports one activity entry per transaction and tracked address, not one entry per transfer.

• Direction. incoming if your address does not spend any input of the transaction. self if it spends an input and every output with an address pays back to it. outgoing in all other cases.
• Net value. The total of the outputs that pay your address, minus the total of the inputs that it spends. A negative value means that the balance of the address went down.
• Inputs and outputs. The full lists for the transaction, so that you can identify change outputs and the other parties.
• Amounts. Integer strings in satoshis (1 BTC = 100,000,000 satoshis).

Example response

When a transaction in a new block involves one of the addresses that you track, you receive a response like this:

{
  "webhookId": "wh_k2p9xw4mz7qv1ndt",
  "id": "whevt_5tq8rmc2xwz0jh6b",
  "createdAt": "2026-11-10T00:56:04.512Z",
  "type": "ADDRESS_ACTIVITY",
  "event": {
    "network": "BITCOIN_MAINNET",
    "source": "bitcoin-core",
    "activity": [
      {
        "address": "3KMmeqPeQcngyTehdfSwsGqvxfU7J7qtc8",
        "txid": "bd5dff8db6e16d9fd823b0e03e7cfe680f7d67414ca1a7aca58c697da00cf6e2",
        "blockHeight": 975230,
        "blockHash": "0000000000000000000194f9d869aacbcc933214cf1e5eacadaf42aabe509da0",
        "blockTimestamp": "2026-11-10T00:55:51Z",
        "confirmations": 1,
        "status": "confirmed",
        "direction": "incoming",
        "netValue": "27654",
        "fee": "536",
        "coinbase": false,
        "inputs": [
          {
            "address": "39tnEqBuDFPhvRVyB4DooenynzD5bXvv1f",
            "value": "28190",
            "prevTxid": "3dfeda50839a9aa10e0de6ec712e56958a7d1fa67e5a63a45d8d966a57138ae4",
            "prevVout": 54
          }
        ],
        "outputs": [
          {
            "address": "3KMmeqPeQcngyTehdfSwsGqvxfU7J7qtc8",
            "value": "27654",
            "vout": 0,
            "scriptType": "scripthash"
          }
        ],
        "removed": false
      }
    ]
  }
}

Field definitions

Below you can find descriptions for each field of the response.

How to set up a Bitcoin Address Activity webhook

Events start with the next block after you create the webhook. Earlier transactions are not sent.

Useful endpoints