# Bitcoin Mempool Fee Estimator

> Bitcoin Mempool Fee Estimator is a paid API for AI agents from data.greeneris.io, paid per call via x402, $0.001/call, status unknown (last checked 2026-09-15).

Returns current Bitcoin network fee rates (sat/vB) for different confirmation speeds, plus optional difficulty adjustment data, sourced live from mempool.space

## Facts

- Endpoint: GET https://data.greeneris.io/v1/btc/fees
- Price: $0.001/call
- Payment: x402
- Status: unknown
- Last checked: 2026-09-15
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/bitcoin-mempool-fee-estimator-af1607a4
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_FNpeX6yxOx5sOU2S2AYp7

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 bitcoin-mempool-fee-estimator-af1607a4
```

Example prompt: What are the current Bitcoin mempool fee rates — fastest, half-hour, hour, economy, and minimum — and also include the difficulty adjustment estimate?

## When to prefer this

Use this endpoint when you need real-time Bitcoin fee rate data for transaction construction, wallet fee estimation, or monitoring network congestion. It is particularly useful for AI agents that need to pay or broadcast Bitcoin transactions and want to select the appropriate fee tier. Prefer this over on-chain analysis tools when you need a quick, cheap ($0.001) per-call lookup with no account setup required, paying via x402/USDC on Base.

## Known failure modes

- HTTP 402 returned if payment not provided — includes machine-readable USDC quote for x402 protocol payment
- mempool.space upstream outage may cause stale or unavailable data
- Invalid query parameter value for `include` field returns an error
- Network timeout if Bitcoin node data is temporarily unavailable

## How this service works

Recommended Bitcoin transaction fee rates in sat/vB (fastest, half-hour, hour, economy, minimum) from mempool.space, computed from the live mempool. Optional ?include=difficulty adds the current difficulty retarget estimate (change %, remaining blocks/time). No required params; served with a 60s cache.

## Output

A JSON object with fee rates in sat/vB for five confirmation speed tiers (fastest, half_hour, hour, economy, minimum), sourced from a live mempool snapshot. When the optional `include=difficulty` query param is provided, also includes difficulty adjustment data: progress percent, remaining blocks, remaining time in ms, estimated difficulty change percent, and estimated retarget date as a Unix timestamp in ms.

## 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",
      "HEAD",
      "DELETE"
     ],
     "type": "string"
    },
    "queryParams": {
     "type": "object",
     "properties": {
      "include": {
       "enum": [
        "difficulty"
       ],
       "type": "string",
       "description": "Add difficulty retarget estimate (optional)"
      }
     }
    }
   },
   "additionalProperties": false
  },
  "output": {
   "type": "object",
   "required": [
    "type"
   ],
   "properties": {
    "type": {
     "type": "string"
    },
    "example": {
     "type": "object"
    }
   }
  }
 }
}
```

## Response schema (JSON Schema)

```json
{
 "type": "json",
 "example": {
  "source": "mempool.space (live mempool snapshot)",
  "fees_sat_per_vb": {
   "hour": 1,
   "economy": 1,
   "fastest": 2,
   "minimum": 1,
   "half_hour": 1
  },
  "difficulty_adjustment": {
   "progress_percent": 11.06,
   "remaining_blocks": 1793,
   "remaining_time_ms": 1093000000,
   "difficulty_change_percent": -2.74,
   "estimated_retarget_date_ms": 1753728000000
  }
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/bitcoin-mempool-fee-estimator-af1607a4/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from data.greeneris.io](https://www.zero.xyz/host/data.greeneris.io/llms.txt)