# Exa Web Answer with Citations

> Exa Web Answer with Citations is a paid API for AI agents from market.datapackvibe.com, paid per call via x402, $0.07/call, status unknown (last checked 2026-10-10).

Ask a natural language question and receive an AI-generated answer with cited web sources, powered by Exa search via BlockRun

## Facts

- Endpoint: POST https://market.datapackvibe.com/x402/assistant-web-answer-with-citations?utm_source=zero.xyz
- Price: $0.07/call
- Payment: x402
- Status: unknown
- Last checked: 2026-10-10
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/exa-web-answer-with-citations-020a9c92
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_6xhyhFwI6gJ3an_3Avorj

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 exa-web-answer-with-citations-020a9c92 -d '<json body>'
```

Example prompt: Can you look up what the HTTP 402 status code is used for and give me an answer with links to the actual sources that back it up?

## When to prefer this

Choose this endpoint when you need a concise AI-generated answer to a factual or research question AND require cited web sources to accompany it — especially when downstream consumers or users need to verify claims. Prefer this over a raw search API when you want a synthesized answer rather than a list of raw results, and over a general LLM when you need grounding in current web content with traceable references. At $0.07 USDC per call it suits low-volume, high-value research queries rather than bulk lookups.

## Known failure modes

- Query too short or empty — rejected by schema validation (minLength:1)
- Query exceeds 500 characters — rejected by schema validation (maxLength:500)
- Exa search returns no relevant results for an obscure or ambiguous query
- Payment of 0.07 USDC not fulfilled — 402 response, no answer returned
- Upstream Exa or BlockRun service unavailability causes timeout or 5xx error
- Answer generated but citations are low-quality or tangentially related to the question

## How this service works

Exa Web Answer with Citations: Ask a question and receive an Exa-generated answer with source citations through BlockRun. Query is sent to those providers. Returns retrieval time and source records. Review the answer and citations; this service does not independently verify source claims. 0.07 USDC includes one sourced answer.

## Output

Returns an AI-generated answer to the submitted question along with source citations (URL records and retrieval metadata) drawn from Exa's web index. Includes retrieval time and the underlying source records used to construct the answer. Note: the service does not independently verify the accuracy of source claims.

## Request schema (JSON Schema)

```json
{
 "type": "object",
 "properties": {
  "query": {
   "type": "string",
   "default": "What is the HTTP 402 status code used for?",
   "maxLength": 500,
   "minLength": 1
  }
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/exa-web-answer-with-citations-020a9c92/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from market.datapackvibe.com](https://www.zero.xyz/host/market.datapackvibe.com/llms.txt)