Balance changes — balance

Subscribe to the balance channel to follow an address's balance. By default you receive the confirmed balance after each block; add pending: true to receive the pending (mempool) balance delta instead.

{ "action": "subscribe", "channel": "balance", "address": "bc1qw508d6qejxtdg4y5r3zarvary0c5xw7kv8f3t4" }
{ "action": "subscribe", "channel": "balance", "address": "bc1qw508d6qejxtdg4y5r3zarvary0c5xw7kv8f3t4", "pending": true }

balance — confirmed

Sent once per block in which the address's balance changed.

{
  "type": "balance",
  "address": "bc1qw508d6qejxtdg4y5r3zarvary0c5xw7kv8f3t4",
  "confirmedSat": "12395678"
}

Field	Type	Description
type	string	Always "balance".
address	string	The subscribed address.
confirmedSat	string	New confirmed balance in the smallest unit (satoshis), as a string — the same field name the REST address-balance endpoint returns. Divide by 100,000,000 for whole coins.

pending_balance — pending (pending: true)

Sent whenever the address's pending balance changes — a new pending transaction touches it, or one of its pending transactions confirms or expires.

{
  "type": "pending_balance",
  "address": "bc1qw508d6qejxtdg4y5r3zarvary0c5xw7kv8f3t4",
  "pendingSat": "-50000"
}

Field	Type	Description
type	string	Always "pending_balance".
address	string	The subscribed address.
pendingSat	string	Signed pending delta in the smallest unit (satoshis), as a string; negative if net-spending. "0" when there are no pending transactions.

Optional & native-value only

Pending events are an optional feature and may not be available on every network. They cover native value only — fees are not reflected in the delta. Subscribing where pending tracking is unavailable succeeds, but no pending events arrive.