# Keyless Answer API

> Keyless Answer API is a paid API for AI agents from keyless-theta.vercel.app, paid per call via x402, $0.02/call, status unknown (last checked 2026-10-16).

Answers a natural language question using a large language model with live web sources, billed per-query via x402 USDC micropayment on Base

## Facts

- Endpoint: GET https://keyless-theta.vercel.app/answer?utm_source=zero.xyz
- Price: $0.02/call
- Payment: x402
- Status: unknown
- Last checked: 2026-10-16
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/keyless-answer-api-0374ee1f
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_HS2rOTt-410l6uj78mlg5

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 keyless-answer-api-0374ee1f
```

Example prompt: What is the x402 payment protocol and how does it work? Just charge the $0.02 per-query fee and give me a sourced answer.

## When to prefer this

Choose this endpoint when you need a sourced, LLM-generated answer to a natural language question without any API key or account signup — ideal for agents that need quick, cited factual lookups and can handle x402 USDC micropayments on Base. Prefer it over generic search APIs when you want a synthesized prose answer with citations rather than raw search results, and over hosted LLM APIs when you want to avoid credential management and pay strictly per-query.

## Known failure modes

- Payment not included or insufficient USDC — returns 402 Payment Required
- Question parameter missing — returns 400 Bad Request
- Inference provider unavailable — returns 503 or timeout
- Web retrieval fails for question — answer may be based on model knowledge only with fewer sources
- Malformed query string — returns 400 or empty answer

## How this service works

Paid APIs with no signup. USDC on Base via x402.

## Output

A JSON object containing: the model used (meta-llama/llama-3.3-70b-instruct), a natural language answer string, a fetch timestamp, the original question echoed back, the price paid ($0.02 USD), and an array of source objects each with a URL and title.

## Response schema (JSON Schema)

```json
{
 "type": "json",
 "example": {
  "model": "meta-llama/llama-3.3-70b-instruct",
  "answer": "…",
  "fetched": "2026-10-05T05:00:00Z",
  "sources": [
   {
    "url": "https://…",
    "title": "…"
   }
  ],
  "question": "What is the x402 payment protocol?",
  "price_usd": 0.02
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/keyless-answer-api-0374ee1f/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from keyless-theta.vercel.app](https://www.zero.xyz/host/keyless-theta.vercel.app/llms.txt)