# Bitcoin Fee Market Analytics API

> Bitcoin Fee Market Analytics API is a paid API for AI agents from api.carbon-cashmere.de, paid per call via x402, $0.02/call, status down (last checked 2026-09-14).

Returns current Bitcoin mempool fee-tier estimates for 1/3/6/12/24/144-block confirmations plus historical fee percentiles, SegWit adoption, UTXO delta, and fee elasticity metric

## Facts

- Endpoint: GET https://api.carbon-cashmere.de/v1/bitcoin/fee-market
- Price: $0.02/call
- Payment: x402
- Status: down
- Last checked: 2026-09-14
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/api-carbon-cashmere-de-8bc1b3f6
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_jBvSszZd9mioIQ9c2kECI

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 api-carbon-cashmere-de-8bc1b3f6
```

Example prompt: What are the current Bitcoin mempool fee estimates for 1-block and 144-block confirmation targets, and what does the fee elasticity ratio look like right now — plus SegWit adoption and UTXO delta?

## When to prefer this

Choose this endpoint when you need a comprehensive, node-backed snapshot of the Bitcoin fee market combining real-time mempool fee tiers with historical percentile context and fee elasticity, SegWit adoption, and UTXO delta — all in one call. Prefer this over generic blockchain explorers when you need structured analytics for fee estimation decisions, mempool research, or trend monitoring.

## Known failure modes

- Node connectivity issue — Bitcoin node unreachable, returns 503 or timeout
- Invalid query parameters — returns 400 with validation error
- Payment not processed — x402 payment required before data is returned
- Rate limit exceeded — too many requests in short window, returns 429
- Historical N blocks parameter out of range — returns 400 if N exceeds max allowed

## How this service works

Professional crypto market intelligence. Real-time prices, signals, and market scoring.

## Output

A JSON object containing: current mempool fee estimates in sat/vB for 1, 3, 6, 12, 24, and 144-block confirmation targets; historical fee percentiles (10th, 25th, 50th, 75th, 90th) over the last N blocks; a fee elasticity metric (next-block / 144-block ratio) indicating current price sensitivity; current SegWit adoption percentage; and UTXO set delta. All data is node-backed and labeled as informational research.

## Request schema (JSON Schema)

```json
{
 "type": "object",
 "properties": {
  "properties": {
   "type": "string"
  }
 }
}
```

## Response schema (JSON Schema)

```json
{
 "type": "json",
 "example": {
  "_meta": {
   "disclaimer": "Informational research data only — not investment advice."
  },
  "mempool": {
   "size_mb": 1.86,
   "pressure": "low",
   "tx_count": 5976,
   "fee_trend": "stable"
  },
  "fee_elasticity": 2,
  "blocks_analyzed": 144,
  "fee_current_satvb": {
   "3_block_satvb": 1,
   "6_block_satvb": 1,
   "144_block_satvb": 1,
   "next_block_satvb": 2
  },
  "fee_historical_over_blocks": {
   "segwit_pct_median": 0.91,
   "feerate_median_p50": 3.2,
   "feerate_median_p90": 12.4
  }
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/api-carbon-cashmere-de-8bc1b3f6/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from api.carbon-cashmere.de](https://www.zero.xyz/host/api.carbon-cashmere.de/llms.txt)