UTXO metric
Old Spent Value 1y API
Spent prevout value aged at least 52,560 blocks (approximately one year) in each closed interval. Unit: sats (satoshis).
Use GET /v1/metrics/utxo/old_spent_value_1y with X-API-Key authentication, a=BTC, i=10m or 1h or 1d, and optional UTC millisecond bounds.