ClaimReview API & Google Fact Check Tools API

ClaimReview is the schema.org type that powers fact-check rich results in Google Search, Bing, and across the open-data fact-checking ecosystem. It was developed by Duke Reporters' Lab and the Google News Initiative, and it's the single data contract that lets a fact-check published by AFP, Snopes, or PolitiFact be re-surfaced by aggregators (like FAXTR) and search engines.

This guide covers three layers: (1) emitting ClaimReview as a publisher, (2) querying the Google Fact Check Tools API as a consumer, and (3) what the upcoming FAXTR API will add on top.

1. ClaimReview structured data (publishers)

If you publish fact-checks, embedding ClaimReview JSON-LD on each fact-check page makes them eligible for Google's Fact Check rich result and surfaces them in the Fact Check Explorer. The minimum required fields are claimReviewed, reviewRating, url, and author.

{
  "@context": "https://schema.org",
  "@type": "ClaimReview",
  "datePublished": "2026-05-20",
  "url": "https://example.org/fact-check/iran-strike-claim",
  "claimReviewed": "Iran officially declared war on Israel on May 19, 2026.",
  "itemReviewed": {
    "@type": "Claim",
    "appearance": "https://example.com/social-post/12345",
    "firstAppearance": {
      "@type": "CreativeWork",
      "url": "https://x.com/example/status/12345",
      "datePublished": "2026-05-19"
    },
    "author": { "@type": "Person", "name": "@example_account" }
  },
  "author": {
    "@type": "Organization",
    "name": "Example Fact Check",
    "url": "https://example.org"
  },
  "reviewRating": {
    "@type": "Rating",
    "ratingValue": 1,
    "bestRating": 5,
    "worstRating": 1,
    "alternateName": "False"
  }
}

Validate the markup with Google's Rich Results Test before deploying. The Duke Reporters' Lab also maintains a Schema.org ClaimReview Generator that produces compliant JSON-LD from a form.

2. Google Fact Check Tools API (consumers)

The Google Fact Check Tools API exposes the same dataset that powers Fact Check Explorer. It's free, requires an API key from Google Cloud Console, and supports per-claim search with language filtering.

# Search the Fact Check Tools API for a claim
# Docs: https://developers.google.com/fact-check/tools/api

curl -G 'https://factchecktools.googleapis.com/v1alpha1/claims:search' \
  --data-urlencode 'query=Iran war declaration' \
  --data-urlencode 'languageCode=en' \
  --data-urlencode 'key=YOUR_API_KEY'

Each result returns the original publisher, the claim text, the rating, and a link back to the source page. The dataset is global but English- and Spanish-dominant; coverage for Korean, Japanese, and Arabic is thinner, which is one reason FAXTR augments it with regional fact-checker feeds.

3. The ClaimReview Project

The ClaimReview Project (Duke Reporters' Lab + Google News Initiative) maintains the open ClaimReview corpus and offers free tooling for publishers — including the ClaimReview Schema Generator and validators. If you're building a fact-check publication, start there before writing your own emitter.

4. FAXTR API (preview)

FAXTR's API is in private beta. It aggregates ClaimReview output from 100+ organizations across 50+ countries and combines it with AI-generation detection and primary-source links — so a single request returns both "is this claim already verified?" and "is this claim plausibly AI-generated?".

# FAXTR API (preview — beta access)
# Endpoint: https://api.faxtr.com/v1/check

curl -X POST 'https://api.faxtr.com/v1/check' \
  -H 'Authorization: Bearer YOUR_API_KEY' \
  -H 'Content-Type: application/json' \
  -d '{
    "claim": "Iran officially declared war on Israel",
    "language": "en"
  }'

# Response: aggregated ClaimReview results from 100+ orgs
# plus an AI-detection score and primary source links.

Approved beta applicants get free Business-tier access. Use cases include LLM guardrails (filter hallucinated claims before they reach users), editorial workflows (auto-flag suspicious claims), and social/UGC platforms (surface fact-check context next to user posts).