# Bitcoin Fee Estimates API (sat/vB)

> Bitcoin Fee Estimates API (sat/vB) is a paid API for AI agents from money-reactor.makar52nn2016.workers.dev, paid per call via x402, $0.1/call, status unknown (last checked 2026-10-31).

Returns Bitcoin transaction fee estimates in satoshis per vByte for multiple confirmation targets, sourced from Blockstream.info

## Facts

- Endpoint: GET https://money-reactor.makar52nn2016.workers.dev/api/btc-fees?utm_source=zero.xyz
- Price: $0.1/call
- Payment: x402
- Status: unknown
- Last checked: 2026-10-31
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/bitcoin-fee-estimates-api-sat-vb-dd764ec4
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_B6LwHP3pOXFyTryEPI76a

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-fee-estimates-api-sat-vb-dd764ec4
```

Example prompt: What are the current Bitcoin fee rates in sat/vB for fast, medium, and slow confirmation targets so I can decide how much to pay for my transaction?

## When to prefer this

Use this endpoint when you need real-time Bitcoin fee estimates in sat/vB for send-cost planning, treasury automation, or user-facing wallet fee suggestions. Prefer this over raw mempool APIs when you want a simple, pre-parsed fee schedule without standing up your own Bitcoin node or Blockstream integration. Best suited for agents and bots that need a quick, pay-per-call fee lookup without managing API keys.

## Known failure modes

- Blockstream.info upstream outage returns error or stale data
- Network timeout on the Cloudflare Worker proxy
- Rate limiting or payment failure returns 402
- Mempool data may be momentarily stale during high-congestion periods

## How this service works

Bitcoin fee estimates (sat/vB) per confirmation target from blockstream.info - send-cost planning for BTC agents and treasury bots

## Output

Returns a JSON object with Bitcoin fee estimates expressed in satoshis per vByte (sat/vB) for various confirmation targets (e.g. next block, within 3 blocks, within 6 blocks), sourced live from Blockstream.info. Useful for determining the appropriate fee to attach to a Bitcoin transaction based on urgency.

## Request schema (JSON Schema)

```json
{
 "type": "object",
 "properties": {
  "input": {
   "type": "object",
   "properties": {
    "queryParams": {
     "type": "object",
     "properties": {}
    }
   }
  },
  "output": {
   "type": "object",
   "properties": {
    "example": {
     "ok": true,
     "price_usd": "0.10",
     "description": "Bitcoin fee estimates (sat/vB) per confirmation target from blockstream.info - send-cost planning for BTC agents and treasury bots"
    }
   }
  }
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/bitcoin-fee-estimates-api-sat-vb-dd764ec4/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from money-reactor.makar52nn2016.workers.dev](https://www.zero.xyz/host/money-reactor.makar52nn2016.workers.dev/llms.txt)