Exa grounded answer

Ask a question and get a written answer with the sources it was drawn from. Exa searches its index, reads the pages and composes the answer, returning the citation list (title, URL, published date) alongside it so every claim can be checked. Model-backed: the answer text is generated, the citations are retrieved.

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Input

Example output

{
  "source": "exa",
  "fetchedAt": "2026-09-13T20:00:00.000Z",
  "query": "What is the x402 payment protocol and who uses it?",
  "answer": "x402 is an HTTP-native payment protocol that settles stablecoin payments per request ...",
  "citationCount": 1,
  "citations": [
    {
      "title": "What is the x402 payment protocol?",
      "url": "https://example.com/x402-explained",
      "publishedDate": "2026-08-02T00:00:00.000Z",
      "author": null,
      "text": null
    }
  ]
}

Try it - see the 402 challenge (free)

curl -i -X POST https://agent402.tools/api/exa-answer \
  -H "Content-Type: application/json" \
  -d '{"query":"What is the x402 payment protocol and who uses it?"}'

The response is HTTP 402 Payment Required with exact payment requirements. Any x402 v2 client pays automatically and retries:

Paid call (JavaScript agent)

import { wrapFetchWithPayment } from "@x402/fetch";
import { x402Client } from "@x402/core/client";
import { registerExactEvmScheme } from "@x402/evm/exact/client";
import { privateKeyToAccount } from "viem/accounts";
import { metaTitle, metaDescription } from "./seo-meta.js";

const client = new x402Client();
registerExactEvmScheme(client, { signer: privateKeyToAccount(KEY) });
const payFetch = wrapFetchWithPayment(fetch, client);

const res = await payFetch("https://agent402.tools/api/exa-answer", {
  method: "POST",
  headers: { "Content-Type": "application/json" },
  body: JSON.stringify({
    "query": "What is the x402 payment protocol and who uses it?"
  }),
});

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