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Answer Engine with Citations
x402
Answer Engine with Citations is a paid API for AI agents from agentsvc.io, paid per call via x402, $0.008/call, status unknown (last checked 2026-10-11).
Returns an AI-generated answer to a natural language question along with cited source URLs from web, news, or Wikipedia
Price / call$0.008
Success—
StatusUnknown
How this service works
86 APIs for AI agents: web scraping and crawling to Markdown, AI summaries, data extraction and cited answers, screenshots and PDF, PDF, OCR and document conversion, news, paper and developer search and more, paid per call with USDC on Base, Solana, Polygon or Arbitrum via x402. No account, no API key, free sample on every service.
Output
A JSON object containing a natural-language answer generated by Claude, a list of numbered source citations with URLs and titles, the original question, which sources were searched (web/news), a timestamp, and the model name used. Sources are drawn from Wikipedia, GDELT news index, and Hacker News.
Example use cases
Fact-checking a business claim
“I need a cited answer to this question: 'Who currently owns Twitter and what did they pay for it?' — search the web and give me sources I can check.”
Research assistant for news topics
“What are the latest developments on the US Federal Reserve interest rate decisions? Search news sources and give me an answer with citations.”
Multilingual knowledge lookup
“Can you answer the question 'What is the Schengen Area and which countries are in it?' in German, with cited sources?”
Technical details
Endpoint
POSThttps://agentsvc.io/api/v1/proxy/answer-with-sources?utm_source=zero.xyzWhen to prefer
Choose this endpoint when you need a factual answer grounded in verifiable sources rather than a raw search result list or an unattributed AI response. It's ideal when you need citations alongside the answer for transparency, fact-checking, or user trust. Prefer it over plain web-scraping when you want synthesized prose rather than raw HTML, and over a bare LLM call when you need source attribution. Best for factual, research-oriented, or news-backed questions up to 400 characters.
Side effects
- Question exceeds 400-character limit — returns error
- No relevant sources found for highly niche questions — answer may be unsourced or low-confidence
- Network or upstream search failure — returns error or empty sources
- Language not recognized — may default to English output
- Ambiguous source selection when source=auto — may not match user intent
Input
Schema · Request body
| Field | Type | Description |
|---|---|---|
| source | string | |
| language | string | Answer language, e.g. German; default English |
| question | string | The question, max 400 chars |
Output
Schema · Response
{
"type": "json",
"example": {
"data": {
"note": "Sources come from Wikipedia and our news index (GDELT, Hacker News), not from...",
"model": "claude-haiku-5-5",
"answer": "A Legal Entity Identifier (LEI) is a unique 20-character alphanumeric code th...",
"sources": [
{
"n": 1,
"url": "https://en.wikipedia.org/wiki/Legal_Entity_Identifier",
"title": "Legal Entity Identifier - Wikipedia"
}
],
"question": "What is a Legal Entity Identifier used for?",
"searched": [
"web"
],
"answered_at": "2026-10-10T09:58:26.892Z"
},
"success": true
}
}Tags
x402
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