# 2s.io Bitcoin UTXO Lookup

> 2s.io Bitcoin UTXO Lookup is a paid API for AI agents from 2s.io, paid per call via x402, $0.0036/call, status unknown (last checked 2026-09-14).

Returns all unspent transaction outputs (UTXOs) for a Bitcoin address, sorted largest-first, with txid, output index, value in sats and BTC, confirmation status, and block height.

## Facts

- Endpoint: GET https://2s.io/api/crypto/btc-utxos
- Price: $0.0036/call
- Payment: x402
- Status: unknown
- Last checked: 2026-09-14
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/2s-io-bitcoin-utxo-lookup-06fa4fb5
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_vzfr2g1NZrJf_96u4Zk09

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 2s-io-bitcoin-utxo-lookup-06fa4fb5
```

Example prompt: Can you pull the UTXOs for the Bitcoin address bc1qxy2kgdygjrsqtzq2n0yrf2493p83kkfjhx0wlh and show me which ones are confirmed, sorted by size?

## When to prefer this

Use this endpoint when you need UTXO-level detail for a Bitcoin address — especially for coin selection, building raw transactions, or verifying spendable balance at the output level. Prefer this over balance-only endpoints when you need individual output metadata like txid, vout, confirmation status, and block height.

## Known failure modes

- Invalid or malformed Bitcoin address returns an error response
- Address with no UTXOs returns an empty list
- Limit parameter out of range (below 1 or above 500) causes a validation error
- Network or upstream blockchain data source unavailability causes a 5xx error
- Payment failure or insufficient USDC balance blocks the request (x402 payment required)

## How this service works

Unspent transaction outputs (UTXOs) for a Bitcoin address (free/keyless): each with txid, output index, value (sats + BTC), confirmation status, and block height. Sorted largest-first. For coin selection, balance verification, and wallet tooling.

## Output

A list of UTXOs for the requested Bitcoin address, each containing the transaction ID (txid), output index (vout), value in both satoshis and BTC, confirmation status (confirmed/unconfirmed), and block height. Results are sorted largest-value-first, limited to up to 500 entries.

## 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",
    "queryParams"
   ],
   "properties": {
    "type": {
     "const": "http"
    },
    "method": {
     "const": "GET"
    },
    "queryParams": {
     "type": "object",
     "required": [
      "address"
     ],
     "properties": {
      "limit": {
       "type": "integer",
       "maximum": 500,
       "minimum": 1
      },
      "address": {
       "type": "string",
       "maxLength": 100,
       "minLength": 20
      }
     },
     "additionalProperties": false
    }
   }
  }
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/2s-io-bitcoin-utxo-lookup-06fa4fb5/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from 2s.io](https://www.zero.xyz/host/2s.io/llms.txt)