# chainquery utxoupdatepsbt – Fill PSBT UTXOs via Bitcoin Core

> chainquery utxoupdatepsbt – Fill PSBT UTXOs via Bitcoin Core is a paid API for AI agents from x402.chainquery.com, paid per call via x402, $0.01/call, status unknown (last checked 2026-09-15).

Fills missing UTXO and script data in a PSBT by querying the live UTXO set on chainquery's independent Bitcoin full node (Bitcoin Core utxoupdatepsbt RPC).

## Facts

- Endpoint: GET https://x402.chainquery.com/v1/rpc/utxoupdatepsbt
- 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/chainquery-utxoupdatepsbt-fill-psbt-utxos-via-bitcoin-core-0b88d3cb
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_3IfoWTyAHW4TrYtakzgie

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 chainquery-utxoupdatepsbt-fill-psbt-utxos-via-bitcoin-core-0b88d3cb
```

Example prompt: I have a PSBT that's missing its UTXO inputs — can you call utxoupdatepsbt on chainquery to fill in the missing UTXO and script data so I can sign it? Here's the base64 PSBT: cHNidP8BAH...

## When to prefer this

Use this endpoint when you need to enrich a PSBT with live UTXO data without running your own Bitcoin full node. It is ideal for wallet builders, PSBT signing workflows, and multi-party transaction construction where inputs lack witness/script metadata. Prefer it over alternatives when you want pay-per-call access with no API key setup and trust in an independent (non-custodial) full node.

## Known failure modes

- PSBT inputs reference UTXOs already spent or not found in the UTXO set — result may be partial or unchanged
- Malformed or invalid base64 PSBT string — RPC returns an error
- Missing required 'params' query parameter containing the PSBT — request fails
- Payment of $0.01 USDC not fulfilled via x402 protocol — 402 Payment Required returned
- Node temporarily unavailable — connection or timeout error

## How this service works

chainquery Bitcoin RPC: pay-per-call Bitcoin Core over x402, no API key. Fill a PSBT's missing UTXO and script data from the UTXO set, via chainquery's independent full node. Bitcoin Core utxoupdatepsbt.

## Output

Returns the Bitcoin Core utxoupdatepsbt result: an updated PSBT (base64-encoded) with any missing UTXO fields (witness_utxo, non_witness_utxo, scriptPubKey, amount, redeemScript, witnessScript) populated from the current live UTXO set on chainquery's full node.

## 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": {
      "params": {
       "type": "string",
       "description": "optional: JSON-encoded array of positional RPC params"
      }
     }
    }
   },
   "additionalProperties": false
  },
  "output": {
   "type": "object",
   "required": [
    "type"
   ],
   "properties": {
    "type": {
     "type": "string"
    },
    "example": {
     "type": "object",
     "properties": {
      "result": {
       "description": "utxoupdatepsbt result"
      }
     }
    }
   }
  }
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/chainquery-utxoupdatepsbt-fill-psbt-utxos-via-bitcoin-core-0b88d3cb/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from x402.chainquery.com](https://www.zero.xyz/host/x402.chainquery.com/llms.txt)