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Second Opinion Async Claim Verification
x402
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 2026-09-13).
Asynchronously verifies a claim using adversarial web research, returning a job ID immediately so results can be polled later; supports Solana payments.
Price / call$0.2
Success—
StatusUnknown
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.
Example use cases
Async fact-check for news article claims
“I want to verify the claim 'COVID-19 vaccines caused more deaths than COVID-19 itself' using live web research — submit it as a background job and give me the polling URL so I can check back for the verdict.”
Solana-funded claim verification pipeline
“I need to verify the claim 'Apple became the first $3 trillion company in 2023' and I'm paying with Solana — submit it asynchronously so I can poll for the result without blocking my workflow.”
Automated misinformation screening queue
“Queue up a background adversarial check on this claim: 'The Great Wall of China is visible from space with the naked eye' — return the job ID so my system can poll for the verdict later.”
Technical details
Endpoint
POSThttps://secondopinionx402.com/v1/verify/asyncWhen to prefer
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.
Side effects
- 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
Input
Schema · Request body
| Field | Type | Description |
|---|---|---|
| inputrequired | object | |
| output | object |
Tags
x402
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