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Bitcoin Smart Fee Curve API
x402
Bitcoin Smart Fee Curve API is a paid API for AI agents from api.carbon-cashmere.de, paid per call via x402, $0.02/call, status unknown (last checked 2026-09-14).
Returns Bitcoin smart-fee estimates across 1/3/6/12/24/144-block confirmation targets with trend classification derived from a 2-hour moving average, sourced from an own-node estimatesmartfee call.
Price / call$0.02
Success—
StatusUnknown
How this service works
Bitcoin smart-fee curve for 1/3/6/12/24/144-block confirmation targets + trend classification (rising/stable/falling/surging) from 2h moving average.
Output
A fee curve object containing sat/vByte fee estimates for each of the 1, 3, 6, 12, 24, and 144-block confirmation targets, a trend classification label (rising/stable/falling/surging) derived from a 2-hour moving average, and min relay fee context — all sourced live from an own Bitcoin node's estimatesmartfee RPC.
Example use cases
Example prompt
“What are the current Bitcoin fee rates for 1, 6, and 24-block confirmation targets, and is the fee market trending rising, stable, or falling right now?”
Technical details
Endpoint
GEThttps://api.carbon-cashmere.de/v1/btc-derivatives/fee-curveWhen to prefer
Use this endpoint when an AI agent needs real-time Bitcoin fee data across multiple confirmation horizons in a single call, especially for fee-aware transaction timing or execution planning. Prefer this over generic mempool explorers when you also need trend classification (rising/stable/falling/surging) to decide whether to transact now or wait. Ideal for automated agents that must optimize BTC transaction costs dynamically.
Side effects
- Node connectivity issue — own Bitcoin node temporarily unavailable, returns 503
- Fee estimation unavailable — mempool insufficient data for certain block targets, partial curve returned
- Rate limiting — exceeded call quota, returns 429
- Invalid endpoint path — returns 404
Input
Schema · Request body
| Field | Type | Description |
|---|---|---|
| properties | string |
Output
Schema · Response
{
"type": "json",
"example": {
"trend": "stable",
"sat_vb": {
"1block": 4.2,
"3block": 3.1,
"6block": 2.8,
"12block": 2.5,
"24block": 2.1,
"144block": 1.4
},
"pressure": "low",
"min_relay_fee_sat_vb": 1
}
}Tags
x402
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