# Bitcoin Fee Estimator Accuracy Scoreboard

> Bitcoin Fee Estimator Accuracy Scoreboard is a paid API for AI agents from cdp.bitcoinsapi.com, paid per call via x402, $0.005/call, status down (last checked 2026-09-15).

Returns a ranked leaderboard of Bitcoin fee estimation sources ordered by historical accuracy (mean absolute error in sat/vB) over a configurable lookback window.

## Facts

- Endpoint: GET https://cdp.bitcoinsapi.com/api/v1/fees/observatory/scoreboard
- Price: $0.005/call
- Payment: x402
- Status: down
- Last checked: 2026-09-15
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/cdp-bitcoinsapi-com-5d638419
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_98II4ks4wDcWiIPSkzkBZ

Status and success rate cover calls made through Zero and Zero's own probes. Third-party monitors may report differently.

## How to call it through Zero

Zero handles the 402 payment challenge and records the run. With the Zero CLI installed (`npm i -g @zeroxyz/cli`):

```sh
zero fetch --capability cdp-bitcoinsapi-com-5d638419
```

Example prompt: Which Bitcoin fee estimator has been most accurate over the past 7 days — show me the full scoreboard ranked by how closely each source predicted actual fees?

## When to prefer this

Use this endpoint when you need to decide which Bitcoin fee estimation source to trust before making a fee-sensitive transaction decision. Ideal for agents that aggregate multiple fee sources and need to weight or select the most historically accurate one. Prefer this over raw fee endpoints when you need meta-level accuracy analytics rather than a current fee estimate.

## Known failure modes

- Invalid hours parameter (non-numeric) returns 400 error
- Very short lookback windows (e.g. hours=1) may return sparse sample counts or empty results
- Service unavailable (503) if underlying fee data pipeline is down
- Payment required (402) if x402 micropayment header is missing or insufficient

## How this service works

Satoshi API fee estimator scoreboard: accuracy analytics for choosing which Bitcoin fee source to trust.

## Output

An array of ranked fee-source objects, each with: rank (integer), source name (string), sample count (integer), and mean absolute error in sat/vB (float). Lower MAE = higher rank. Default lookback is 168 hours (7 days).

## Request schema (JSON Schema)

```json
{
 "type": "object",
 "input": {
  "type": "http",
  "method": "GET",
  "resource": "https://cdp.bitcoinsapi.com/api/v1/fees/observatory/scoreboard",
  "queryParams": {
   "hours": {
    "type": "number",
    "default": 168,
    "required": false,
    "description": "Lookback window in hours (default 7 days)"
   }
  }
 },
 "output": {
  "type": "json",
  "schema": {
   "type": "array",
   "items": {
    "type": "object",
    "required": [
     "source",
     "rank"
    ],
    "properties": {
     "rank": {
      "type": "integer"
     },
     "source": {
      "type": "string"
     },
     "sampleCount": {
      "type": "integer"
     },
     "meanAbsoluteErrorSatVb": {
      "type": "number"
     }
    }
   }
  },
  "example": [
   {
    "rank": 1,
    "source": "satoshi-api",
    "sampleCount": 144,
    "meanAbsoluteErrorSatVb": 2.1
   }
  ],
  "mimeType": "application/json"
 },
 "properties": {
  "input": {
   "type": "object",
   "properties": {
    "queryParams": {
     "hours": {
      "type": "number",
      "default": 168,
      "required": false,
      "description": "Lookback window in hours (default 7 days)"
     }
    }
   }
  },
  "output": {
   "type": "object",
   "required": [
    "type",
    "mimeType",
    "example"
   ],
   "properties": {
    "type": {
     "type": "string"
    },
    "schema": {
     "type": "object"
    },
    "example": {
     "type": "object"
    },
    "mimeType": {
     "type": "string"
    }
   }
  }
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/cdp-bitcoinsapi-com-5d638419/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from cdp.bitcoinsapi.com](https://www.zero.xyz/host/cdp.bitcoinsapi.com/llms.txt)