factcheck.search

Search the global corpus of published fact-checks (ClaimReview) by free-text claim. Returns matching claims with the claimant, claim date, and each fact-check review's verdict (textualRating, e.g. "False", "Misleading", "True"), the publisher (PolitiFact, Snopes, FactCheck.org, Reuters Fact Check, AFP, …), the review URL, and review date. Covers every topic — politics, health, science, viral and misinformation claims. Optional language, recency (maxAgeDays), and publisher-site filters. Aggregated by Google from publishers' schema.org ClaimReview data. Use it to check whether a claim has been independently fact-checked and how it was rated, rather than asserting from training data.

price

$0.0018 USDC per call

method

GET/api/factcheck/search

payment

x402 v2 · USDC on Base (EIP-3009) or Solana (SPL transfer)

auth

None. Sign the payment, retry with PAYMENT-SIGNATURE.

tier

Tier 0 — no paid upstream

Parameters

Name	Type	Description
`query`required	string	Free-text claim to search the fact-check corpus for. min 2 chars · max 200 chars
`language`	string	BCP-47 language code (e.g. en, es) to restrict results. min 2 chars · max 8 chars
`maxAgeDays`	integer	Only return reviews published within this many days. min 1 · max 3650
`publisher`	string	Restrict to a publisher site (e.g. factcheck.org, politifact.com). min 2 chars · max 120 chars
`limit`	integer	Max claims to return (1–50, default 10). min 1 · max 50

Code samples

cURLbash

# 1. Probe with no auth → 402 envelope with PaymentRequirements
curl -sS 'https://2s.io/api/factcheck/search?query=xx&language=xx&maxAgeDays=1&publisher=xx&limit=1'

# 2. Sign + retry with PAYMENT-SIGNATURE:
curl -sS 'https://2s.io/api/factcheck/search?query=xx&language=xx&maxAgeDays=1&publisher=xx&limit=1' \
  -H 'PAYMENT-SIGNATURE: <base64-json-payload>'

# Or use the canonical runner (handles probe → sign → retry):
#   EVM_PRIVATE_KEY=0x... node --env-file=.env.local \
#     --experimental-strip-types scripts/x402-pay.ts \
#     'https://2s.io/api/factcheck/search?query=xx&language=xx&maxAgeDays=1&publisher=xx&limit=1'

TypeScript / Node — @2sio/sdktypescript

import { TwoS } from '@2sio/sdk'

const client = new TwoS({
  privateKey: process.env.EVM_PRIVATE_KEY as `0x${string}`,
})

const result = await client.factcheck.search({
  "query": "xx",
  "language": "xx",
  "maxAgeDays": 1,
  "publisher": "xx",
  "limit": 1
})

console.log('endpoint:', result.endpoint)
console.log('cost:', result.costUsd, 'USDC')
console.log('tx:', result.settlement?.txHash)
console.log('data:', result.data)

Python — 2siopython

import os
from twosio import TwoS

client = TwoS(private_key=os.environ["EVM_PRIVATE_KEY"])

result = client.factcheck.search(query="xx", language="xx", maxAgeDays=1, publisher="xx", limit=1)

print("endpoint:", result.endpoint)
print("cost:", result.cost_usd, "USDC")
print("tx:", (result.settlement or {}).get("tx_hash"))
print("data:", result.data)

MCP — Claude Desktop / AgentKit / any MCP hostjson

// 1. Add @2sio/mcp to your MCP host config (Claude Desktop example below).
//    EVM_PRIVATE_KEY funds x402 payments per call.

// claude_desktop_config.json
{
  "mcpServers": {
    "2sio": {
      "command": "npx",
      "args": ["-y", "@2sio/mcp"],
      "env": { "EVM_PRIVATE_KEY": "0x..." }
    }
  }
}

// 2. Once the server is running, agents call this tool via standard MCP:

{
  "jsonrpc": "2.0",
  "id": 1,
  "method": "tools/call",
  "params": {
    "name": "factcheck.search",
    "arguments": {
      "query": "xx",
      "language": "xx",
      "maxAgeDays": 1,
      "publisher": "xx",
      "limit": 1
    }
  }
}

Response

Field	Type	Description
`ok`	boolean	one of: true
`items`	array
`total`	integer	Total matching rows upstream; null when unknown.
`source`	object
`meta`	object

Example response datajson

{
  "ok": true,
  "items": [
    {
      "text": "example",
      "claimant": "example",
      "claimDate": "example",
      "reviews": [
        {
          "publisher": "example",
          "publisherSite": "example",
          "url": "example",
          "title": "example",
          "textualRating": "example",
          "reviewDate": "example",
          "languageCode": "example"
        }
      ]
    }
  ],
  "total": 1,
  "source": {
    "provider": "example",
    "url": "example",
    "license": "example"
  },
  "meta": {
    "query": "example",
    "count": 1
  }
}

Discovery

/api/directory — full catalog of every endpoint
/openapi.json — OpenAPI 3.1 spec (per-op x-payment-info, x402Payment security)
/.well-known/x402 — machine-readable service descriptor for x402-aware crawlers
/.well-known/mcp/server-card.json — MCP SEP-1649 server card
/llms.txt — plain-text manifest for LLM ingestion

2s.io is x402-native. Every call is paid per-request from a USDC-funded EVM wallet on Base — no signup, no API keys, no monthly fees. Source code: github.com/2s-io/sdk.