# klymax402 Fact Checker API

> klymax402 Fact Checker API is a paid API for AI agents from klymax402.com, paid per call via x402, $0.012/call, status unknown (last checked 2026-09-14).

Verifies a factual claim against multiple sources and returns a fact-check result with supporting evidence

## Facts

- Endpoint: GET https://klymax402.com/api/fact-checker/api/check
- Price: $0.012/call
- Payment: x402
- Status: unknown
- Last checked: 2026-09-14
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/klymax402-fact-checker-api-219eea7f
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_mnwy0zAsM_qm27O4Co7F8

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 klymax402-fact-checker-api-219eea7f
```

Example prompt: Can you fact-check the claim 'The Eiffel Tower is 330 meters tall' and give me up to 5 sources that confirm or deny it?

## When to prefer this

Choose this endpoint when an AI agent needs to programmatically verify a specific factual claim with cited sources, especially in research, journalism, or content moderation workflows. It is particularly useful when you need a structured fact-check response rather than a raw web search, and when paying per-call without managing API keys is preferable. Use this over general web search when you specifically need a verdict (true/false/unverified) rather than raw search results.

## Known failure modes

- Claim is too vague or ambiguous to verify — endpoint may return low confidence or no verdict
- No reliable sources found for niche or obscure claims — returns empty source list
- Payment failure via x402 protocol — 402 response if USDC payment not completed
- Rate limiting if too many requests are made in a short period
- max_sources exceeds 10 — likely clamped or returns an error

## How this service works

One MCP endpoint gives your AI agent access to 100 APIs -- crypto, DeFi, web, AI, finance and utilities. No API keys, USDC on Base from $0.003/call.

## Output

Returns a fact-check verdict indicating whether the claim is true, false, or unverified, along with a list of supporting or contradicting sources (up to the requested maximum), potentially including source URLs, credibility signals, and a confidence assessment.

## Request schema (JSON Schema)

```json
{
 "type": "object",
 "properties": {
  "claim": {
   "type": "string",
   "description": "The factual claim to verify (e.g., 'The Eiffel Tower is 330 meters tall')"
  },
  "max_sources": {
   "type": "number",
   "description": "Maximum number of sources to return (default: 5, max: 10)"
  }
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/klymax402-fact-checker-api-219eea7f/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from klymax402.com](https://www.zero.xyz/host/klymax402.com/llms.txt)