# BTC Node Fee Estimator

> BTC Node Fee Estimator is a paid API for AI agents from btcnode.uk, paid per call via x402, $0.001/call, status unknown (last checked 2026-10-02).

Returns a Bitcoin transaction fee estimate for any target confirmation block from 1 to 1008

## Facts

- Endpoint: GET https://btcnode.uk/api/fees/estimate?utm_source=zero.xyz
- Price: $0.001/call
- Payment: x402
- Status: unknown
- Last checked: 2026-10-02
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/btc-node-fee-estimator-375d2e2a
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_FV5FWZPpmcV53W-Rlyl0Y

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 btc-node-fee-estimator-375d2e2a
```

Example prompt: What's the current Bitcoin fee estimate if I want my transaction confirmed within 6 blocks — give me the sat/vbyte rate from btcnode.uk.

## When to prefer this

Choose this endpoint when you need real-time Bitcoin transaction fee estimates sourced directly from a live Bitcoin Core node, especially if you want flexible confirmation-window targeting (any value from 1 to 1008 blocks). Prefer it over mempool.space scrapers or indirect APIs when you want low-cost ($0.001/call), no-signup, programmatic fee lookups with a wide range of block targets.

## Known failure modes

- Invalid block target outside 1-1008 range returns an error
- Bitcoin Core node temporarily unavailable causes timeout or 503
- Insufficient mempool history for accurate estimate at extreme block targets (e.g. 1008) may return a fallback or error
- Payment not received (402) if USDC on Base is not provided

## How this service works

Fee estimate for ANY target block (1-1008) — flat $0.001 per call, USDC on Base, no signup.

## Output

Returns a fee rate estimate (typically in sat/vbyte) appropriate for getting a Bitcoin transaction confirmed within the specified target number of blocks, sourced directly from a live Bitcoin Core node's fee estimation engine.

## Request schema (JSON Schema)

```json
{
 "type": "object",
 "$schema": "https://json-schema.org/draft/2020-12/schema",
 "required": [
  "input"
 ],
 "properties": {
  "input": {
   "type": "object",
   "required": [
    "type",
    "method"
   ],
   "properties": {
    "type": {
     "type": "string",
     "const": "http"
    },
    "method": {
     "enum": [
      "GET"
     ],
     "type": "string"
    },
    "queryParams": {
     "type": "object",
     "properties": {}
    }
   },
   "additionalProperties": false
  },
  "output": {
   "type": "object",
   "required": [
    "type"
   ],
   "properties": {
    "type": {
     "type": "string"
    },
    "example": {
     "type": "object"
    }
   }
  }
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/btc-node-fee-estimator-375d2e2a/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from btcnode.uk](https://www.zero.xyz/host/btcnode.uk/llms.txt)