# Second Opinion Async Claim Verification

> Second Opinion Async Claim Verification is a paid API for AI agents from secondopinionx402.com, paid per call via x402, $0.2/call, status unknown (last checked 2026-09-15).

Asynchronously verifies a claim using adversarial web research, returning a job ID immediately so results can be polled later; supports Solana payments.

## Facts

- Endpoint: POST https://secondopinionx402.com/v1/verify/async
- Price: $0.2/call
- Payment: x402
- Status: unknown
- Last checked: 2026-09-15
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/second-opinion-async-claim-verification-3e4df07f
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_BY679oK_HZZ-Jgax_Ty71

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 second-opinion-async-claim-verification-3e4df07f -d '<json body>'
```

Example prompt: Can you fact-check this claim for me asynchronously — 'The Eiffel Tower is the tallest structure in Europe' — submit it for adversarial web research, give me the job ID, and let me know the poll URL so I can check the verdict when it's ready?

## When to prefer this

Choose this async endpoint over /v1/verify when using Solana for payment (required), when you don't want to block on a long-running web research task, or when orchestrating a pipeline where you can poll for results later. Prefer the sync endpoint only if you need an immediate blocking response and are not on Solana. Choose this over the 'quick' async variant when you need live web research rather than reasoning-only verification.

## Known failure modes

- Payment failure or insufficient USDC/SOL balance — payment rejected before job is created
- Invalid or malformed claim text — job not created
- Job ID not found when polling — may indicate expiry or invalid ID
- Polling URL returns pending status if web research not yet complete
- Service timeout if web research takes too long
- Rate limiting if too many jobs submitted in quick succession

## How this service works

Second Opinion (async): pay, receive a job id in seconds, poll the free result URL for the verdict. Same product as /v1/verify; required for Solana payments, kinder for all rails.

## Output

An immediate response containing a job ID and a free polling URL. Once processing completes, polling the URL returns the full verdict: whether the claim was refuted or supported, supporting evidence from live web research, and a confidence assessment.

## Request schema (JSON Schema)

```json
{
 "type": "object",
 "$schema": "https://json-schema.org/draft/2020-12/schema",
 "required": [
  "input"
 ],
 "properties": {
  "input": {
   "type": "object",
   "required": [
    "type",
    "bodyType",
    "body",
    "method"
   ],
   "properties": {
    "body": {
     "properties": {}
    },
    "type": {
     "type": "string",
     "const": "http"
    },
    "method": {
     "enum": [
      "POST"
     ],
     "type": "string"
    },
    "bodyType": {
     "enum": [
      "json",
      "form-data",
      "text"
     ],
     "type": "string"
    }
   },
   "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/second-opinion-async-claim-verification-3e4df07f/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from secondopinionx402.com](https://www.zero.xyz/host/secondopinionx402.com/llms.txt)