# Bitcoin Transaction Lookup by TXID

> Bitcoin Transaction Lookup by TXID is a paid API for AI agents from chain.openverbs.com, paid per call via x402, $0.006/call, status unknown (last checked 2026-09-15).

Looks up a Bitcoin transaction by its TXID and returns confirmation status, block height and time, fee, fee rate, size, weight, input/output counts, and total output value.

## Facts

- Endpoint: POST https://chain.openverbs.com/v1/btc-tx
- Price: $0.006/call
- Payment: x402
- Status: unknown
- Last checked: 2026-09-15
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/bitcoin-transaction-lookup-by-txid-ffa16fc6
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_h6Tf953WBiem3BWiN2a-d

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-transaction-lookup-by-txid-ffa16fc6 -d '<json body>'
```

Example prompt: Can you check whether Bitcoin transaction 4a5e1e4baab89f3a32518a88c31bc87f618f76673e2cc77ab2127b7afdeda33b has been confirmed, and tell me what block it landed in, how much fee was paid, and the effective fee rate in sat/vB?

## When to prefer this

Use this endpoint when you need authoritative on-chain Bitcoin transaction data — confirmation status, exact fee paid, fee rate, size metrics, and output values — given a specific txid. Prefer this over block explorer web scraping or general-purpose blockchain APIs when you need structured, machine-readable ground truth for payment verification or auditing in an automated agent workflow.

## Known failure modes

- Invalid txid (not 64 hex characters) returns a validation error
- Transaction not found on-chain or in mempool returns a not-found error
- Network or upstream node unavailability may cause timeout or 5xx error
- Unconfirmed mempool transactions may return partial data (no block height/time)

## How this service works

Look up a Bitcoin transaction by txid: confirmation status, block height and time, fee (sats), effective fee rate (sat/vB), size, weight and virtual size, input and output counts, and total output value (sats and BTC). On-chain ground truth for verifying a payment.

## Output

Returns confirmation status (confirmed or unconfirmed), block height and timestamp of inclusion, total fee in satoshis, effective fee rate in sat/vB, raw and virtual transaction size in bytes, weight units, number of inputs and outputs, and total output value expressed in both satoshis and BTC.

## Request schema (JSON Schema)

```json
{
 "$schema": "https://json-schema.org/draft/2020-12/schema",
 "type": "object",
 "properties": {
  "input": {
   "type": "object",
   "properties": {
    "type": {
     "type": "string",
     "const": "http"
    },
    "method": {
     "type": "string",
     "enum": [
      "POST"
     ]
    },
    "bodyType": {
     "type": "string",
     "enum": [
      "json",
      "form-data",
      "text"
     ]
    },
    "body": {
     "type": "object",
     "properties": {
      "txid": {
       "type": "string",
       "minLength": 64,
       "maxLength": 64,
       "description": "Transaction id: 64-character hex string."
      }
     },
     "required": [
      "txid"
     ],
     "additionalProperties": false
    }
   },
   "required": [
    "type",
    "method",
    "bodyType",
    "body"
   ],
   "additionalProperties": false
  }
 },
 "required": [
  "input"
 ]
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/bitcoin-transaction-lookup-by-txid-ffa16fc6/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from chain.openverbs.com](https://www.zero.xyz/host/chain.openverbs.com/llms.txt)