AI-generated answers with web citations via Exa, pay-per-request at $0.01
What it does
The Exa Answer endpoint on StableEnrich returns AI-generated answers to natural language questions, grounded in live web search results and accompanied by source citations. It is a POST endpoint at `https://stableenrich.dev/api/exa/answer` that accepts a JSON body with a required `query` string and optional `stream` and `text` boolean flags. The response includes an `answer` string, an array of `citations` (each with URL, title, author, published date, and optionally extracted text), and a `costDollars` object.
This endpoint is part of the StableEnrich platform, which unifies multiple premium data APIs (Exa, Apollo, Firecrawl, Google Maps, Serper, Whitepages, Clado, Minerva, Reddit, Hunter, Influencer, Cloudflare) behind a single micropayment interface. No API keys or subscriptions are required — authentication is handled via HTTP 402 micropayment using x402 or MPP (Tempo method with pathUSD on Tempo L2). The fixed price is $0.01 per request. Payments can be made on Base mainnet (eip155:8453), Solana, or Tempo.
The endpoint is designed for agent workflows using the agentcash MCP server or CLI, which automates payment processing. Agents discover endpoints via `discover_api_endpoints`, check schemas with `check_endpoint_schema`, and execute calls with `fetch`. The Exa Answer endpoint is useful when an agent needs a concise, cited answer to a factual question without manually parsing search results.
Capabilities
Use cases
- —Agent asks a factual question and needs a concise answer with source URLs
- —Automated research pipelines that need cited summaries of web knowledge
- —Building RAG-style workflows where web search provides grounding for LLM answers
- —Quick fact-checking with traceable citations
- —Replacing manual search-then-summarize steps in agent toolchains
Fit
Best for
- —AI agents needing cited answers to factual questions without parsing raw search results
- —Pay-as-you-go research workflows with no subscription commitment
- —Developers integrating web-grounded QA into agent pipelines via MCP/x402
Not for
- —High-volume batch QA where per-request costs add up (consider direct Exa API subscription)
- —Use cases requiring real-time streaming chat (stream flag exists but endpoint is request-response oriented)
- —Queries requiring private or proprietary data not indexed on the public web
Quick start
# Using agentcash CLI
npx agentcash try https://stableenrich.dev
# Or via MCP fetch tool:
mcp__agentcash__fetch(
url="https://stableenrich.dev/api/exa/answer",
method="POST",
body={"query": "What is the capital of France?"}
)Example
Request
{
"query": "What is the capital of France?"
}Response
{
"answer": "The capital of France is Paris. It has been the capital since the 10th century and is the country's largest city.",
"citations": [
{
"id": "abc123",
"url": "https://en.wikipedia.org/wiki/Paris",
"text": "Paris is the capital and most populous city of France...",
"title": "Paris - Wikipedia",
"author": null,
"publishedDate": null
}
],
"costDollars": {
"total": 0.01
}
}Endpoint
Quality
Full OpenAPI 3.1 schema with request/response definitions, clear pricing ($0.01/request in USD), detailed guidance documentation, and example request bodies are all present. The endpoint returned 405 on HEAD/GET probes (expected since it is POST-only), but the OpenAPI spec and pricing table confirm it is live. Minor deduction because no actual 402 challenge was captured for this specific endpoint.
Warnings
- —Probe returned 405 on HEAD and GET — endpoint is POST-only, which is expected and documented in the OpenAPI spec
- —No direct 402 challenge was captured for this endpoint; liveness inferred from OpenAPI spec and platform documentation
Citations
- —Exa Answer endpoint price is $0.01 per requesthttps://stableenrich.dev
- —Endpoint accepts POST with required query field and optional stream/text booleanshttps://stableenrich.dev/api/exa/answer
- —Payments processed on Base mainnet, Solana, or Tempo via x402/MPPhttps://stableenrich.dev/docs
- —Response includes answer string, citations array, and costDollars objecthttps://stableenrich.dev
- —No API keys or subscriptions required — payment is authenticationhttps://stableenrich.dev/docs