# SignalHarness Bitcoin Weight & vSize Calculator

> SignalHarness Bitcoin Weight & vSize Calculator is a paid API for AI agents from signalharness.ai, paid per call via x402, $0.01/call, status unknown (last checked 2026-09-13).

Computes the weight units and virtual size (vsize) of a Bitcoin transaction from caller-supplied transaction data

## Facts

- Endpoint: POST https://signalharness.ai/api/agent/services/bitcoin_weight_vsize/invoke
- Price: $0.01/call
- Payment: x402
- Status: unknown
- Last checked: 2026-09-13
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/signalharness-bitcoin-weight-vsize-calculator-ebada040
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_NRQMCMxdTMjwg2eu4BZ2e

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 signalharness-bitcoin-weight-vsize-calculator-ebada040 -d '<json body>'
```

Example prompt: Can you calculate the weight and virtual size (vsize) of this Bitcoin transaction so I know how large it is for fee estimation? Here's the raw transaction data: 0100000001...

## When to prefer this

Use this endpoint when you need a fast, on-demand computation of Bitcoin transaction weight and virtual size (vsize) for fee estimation, size auditing, or transaction validation — especially when you already have raw transaction data and need a reliable, paid, agent-native API response with a cryptographic receipt for auditability.

## Known failure modes

- Invalid or malformed transaction hex returns an error or warning
- Input string too short (below 2 characters) rejected at schema validation
- Input exceeding 65536 characters rejected
- Non-Bitcoin transaction data may produce incorrect or warning-laden output
- Network or payment failures return non-succeeded status in receipt

## How this service works

Explore 330 pay-per-call x402 API services and 27 agent-native digital products, with Base USDC pricing, secure Polar checkout, and free discovery.

## Output

Returns a JSON object containing the computed bitcoin_weight_vsize value (the transaction's virtual size), any warnings generated during computation, an evidence_scope field indicating the data source was caller-supplied, plus a full receipt with payment details, latency, request/execution IDs, and a SHA-256 result hash for verification.

## Request schema (JSON Schema)

```json
{
 "type": "object",
 "properties": {
  "bitcoin_weight_request": {
   "type": "string",
   "maxLength": 65536,
   "minLength": 2
  }
 }
}
```

## Response schema (JSON Schema)

```json
{
 "type": "json",
 "example": {
  "replay": false,
  "result": {
   "warnings": [
    "The transaction is not script-validated."
   ],
   "service_id": "bitcoin_weight_vsize",
   "evidence_scope": "caller_supplied_data",
   "bitcoin_weight_vsize": "{\"stripped_size\":61,\"total_size\":61,\"virtual_size\":61,\"weight\":244,\"witness_size\":0}"
  },
  "status": "succeeded",
  "receipt": {
   "asset": "0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913",
   "usage": [],
   "status": "succeeded",
   "network": "eip155:8453",
   "artifacts": [],
   "endedAtMs": 0,
   "latencyMs": 0,
   "paymentId": "example-payment",
   "receiptId": "example-receipt",
   "requestId": "example-request",
   "serviceId": "bitcoin_weight_vsize",
   "executionId": "example-execution",
   "startedAtMs": 0,
   "amountAtomic": "10000",
   "resultSha256": "db4ce73c97862c159f4c92f8e8bdce8b32a36f62b2e2f853388131dc77b8ebe1",
   "serviceVersion": "1.0.0",
   "settlementReference": "0x0000000000000000000000000000000000000000000000000000000000000000"
  },
  "artifacts": [],
  "requestId": "example-request",
  "executionId": "example-execution"
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/signalharness-bitcoin-weight-vsize-calculator-ebada040/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from signalharness.ai](https://www.zero.xyz/host/signalharness.ai/llms.txt)