# BTC Address Balance & UTXO Lookup

> BTC Address Balance & UTXO Lookup is a paid API for AI agents from payai.agentstools.dev, paid per call via x402, $0.01/call, status unknown (last checked 2026-09-15).

Returns confirmed and mempool balance, funded/spent totals, transaction count, and a capped UTXO set for a Bitcoin address (legacy, P2SH, or bech32).

## Facts

- Endpoint: GET https://payai.agentstools.dev/btc/address
- Price: $0.01/call
- Payment: x402
- Status: unknown
- Last checked: 2026-09-15
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/btc-address-balance-utxo-lookup-62c66c8f
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_a0b8Z03KdkYtOL87gWEql

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-address-balance-utxo-lookup-62c66c8f
```

Example prompt: What's the current confirmed and mempool balance for Bitcoin address bc1qxy2kgdygjrsqtzq2n0yrf2493p83kkfjhx0wlh, and can you also show me its UTXO set?

## When to prefer this

Choose this endpoint when you need a quick, pay-per-call lookup of a Bitcoin address's balance and UTXO set without running your own Bitcoin node or subscribing to a full blockchain data provider. Ideal for agents that need on-demand, real-time Bitcoin wallet inspection for any legacy, P2SH, or bech32 address, especially when low-volume spot checks are needed rather than bulk historical data processing.

## Known failure modes

- Invalid or malformed Bitcoin address returns an error
- Testnet addresses are not supported (mainnet only)
- UTXO set is capped — addresses with extremely large UTXO counts may return truncated results
- Network or upstream node downtime may cause timeouts
- Missing required 'address' query parameter returns a 400-level error

## How this service works

Balance and unspent outputs for a Bitcoin address. Returns confirmed and mempool balance, funded and spent totals, transaction count and a capped UTXO set for a legacy, p2sh or bech32 address. Informational, not advice.

## Output

Returns a JSON object containing the confirmed on-chain balance, mempool (unconfirmed) balance, total funded amount, total spent amount, transaction count, and a capped list of unspent transaction outputs (UTXOs) for the queried Bitcoin mainnet address.

## 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",
     "required": [
      "address"
     ],
     "properties": {
      "address": {
       "type": "string",
       "description": "Bitcoin mainnet address (legacy 1.., p2sh 3.., or bech32 bc1..)"
      }
     }
    }
   },
   "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-address-balance-utxo-lookup-62c66c8f/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from payai.agentstools.dev](https://www.zero.xyz/host/payai.agentstools.dev/llms.txt)