# SiteCheck Bitcoin Transaction Lookup

> SiteCheck Bitcoin Transaction Lookup is a paid API for AI agents from api.sitecheck-api.workers.dev, paid per call via x402, $0.002/call, status unknown (last checked 2026-10-19).

Fetches details of a Bitcoin transaction by TXID, including fee, size, inputs, outputs, confirmation status, and block info

## Facts

- Endpoint: GET https://api.sitecheck-api.workers.dev/api/btc/tx?utm_source=zero.xyz
- Price: $0.002/call
- Payment: x402
- Status: unknown
- Last checked: 2026-10-19
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/sitecheck-bitcoin-transaction-lookup-b6d5f5e6
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_yb_-pVwFFOIcwFlkcWEcL

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 sitecheck-bitcoin-transaction-lookup-b6d5f5e6
```

Example prompt: Can you look up Bitcoin transaction f4184fc596403b9d638783cf57adfe4c75c605f6356fbc91338530e9831e9e16 and tell me whether it's confirmed, what fee was paid, and how many inputs and outputs it has?

## When to prefer this

Use this endpoint when you need on-chain Bitcoin transaction data including confirmation status, fees, inputs/outputs, and block details. It sources from mempool.space and is well-suited for per-transaction lookups in agent workflows that need to verify payments, audit fees, or inspect BTC transaction structure without running a full Bitcoin node.

## Known failure modes

- Invalid txid format (not 64 hex characters) returns an error
- Transaction not found in mempool or blockchain returns a not-found error
- Mempool.space upstream unavailability may cause timeout or error
- Missing required txid query parameter returns a validation error

## How this service works

A Bitcoin transaction by txid: confirmed block and time (or unconfirmed), fee in sats and sat/vB, size and virtual size, input and output totals, and whether it signals replace-by-fee. Source: mempool.space. Information only, not financial advice.

## Output

Returns a JSON object with: transaction fee in BTC, sats, and sat/vbyte; RBF flag; transaction size in bytes, vbytes, and weight; txid; input details (count, coinbase flag, total BTC); output details (count, total BTC); confirmation status including block height and block timestamp; source URL (mempool.space); and the timestamp when the check was performed.

## 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",
     "required": [
      "txid"
     ],
     "properties": {
      "txid": {
       "type": "string",
       "description": "Transaction id, 64 hex characters"
      }
     }
    }
   },
   "additionalProperties": false
  },
  "output": {
   "type": "object",
   "required": [
    "type"
   ],
   "properties": {
    "type": {
     "type": "string"
    },
    "example": {
     "type": "object"
    }
   }
  }
 }
}
```

## Response schema (JSON Schema)

```json
{
 "type": "json",
 "example": {
  "fee": {
   "btc": 0,
   "sats": 0,
   "satPerVbyte": 0
  },
  "rbf": false,
  "size": {
   "bytes": 275,
   "vbytes": 275,
   "weight": 1100
  },
  "txid": "f4184fc596403b9d638783cf57adfe4c75c605f6356fbc91338530e9831e9e16",
  "inputs": {
   "count": 1,
   "coinbase": false,
   "totalBtc": 50
  },
  "source": "https://mempool.space/api/tx/f4184fc596403b9d638783cf57adfe4c75c605f6356fbc91338530e9831e9e16",
  "status": {
   "blockTime": "2009-01-12T03:30:25.000Z",
   "confirmed": true,
   "blockHeight": 170
  },
  "outputs": {
   "count": 2,
   "totalBtc": 50
  },
  "checkedAt": "2026-10-14T07:00:19.934Z"
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/sitecheck-bitcoin-transaction-lookup-b6d5f5e6/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from api.sitecheck-api.workers.dev](https://www.zero.xyz/host/api.sitecheck-api.workers.dev/llms.txt)