# x402 Demo API – Quote Endpoint

> x402 Demo API – Quote Endpoint is a paid API for AI agents from x402-demo-api-theta.vercel.app, paid per call via x402, $0.02/call, status unknown (last checked 2026-10-10).

Returns a price quote for a selected data service (AI/LLM, crypto prices, web search, translation, trending topics, sentiment analysis, etc.) before executing the paid call via x402 protocol on Base mainnet.

## Facts

- Endpoint: POST https://x402-demo-api-theta.vercel.app/api/quote?utm_source=zero.xyz
- Price: $0.02/call
- Payment: x402
- Status: unknown
- Last checked: 2026-10-10
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/x402-demo-api-quote-endpoint-f2d8fc70
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_jdekjC2dYm7IYMQer10zI

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 x402-demo-api-quote-endpoint-f2d8fc70 -d '<json body>'
```

Example prompt: Before I commit to paying, can you get me a price quote for calling the crypto price endpoint on the x402 Demo API so I know exactly how much USDC it'll cost me?

## When to prefer this

Use this endpoint when you need to check the cost of a specific data service call before committing to a payment. It is a pre-flight quote step in the x402 micropayment flow — call this before executing the actual paid endpoint to confirm pricing and avoid unexpected charges.

## Known failure modes

- Invalid or unsupported service type returns 400 error
- Missing required query parameters returns 400 with validation error
- x402 payment infrastructure unavailable returns 503
- Rate limiting or quota exceeded returns 429
- Malformed request body returns 400

## How this service works

Paid API with real data: AI/LLM, crypto prices, web search, translation, trending topics, sentiment analysis, aggregator, and more. All endpoints use x402 protocol on Base mainnet.

## Output

Returns a quote object containing the estimated USDC cost for the requested service call on Base mainnet, along with relevant metadata about the endpoint being quoted, enabling the agent to confirm pricing before executing the actual paid request.

## Request schema (JSON Schema)

```json
{
 "type": "object",
 "$schema": "https://json-schema.org/draft/2020-12/schema",
 "required": [
  "input"
 ],
 "properties": {
  "input": {
   "type": "object",
   "required": [
    "type",
    "method",
    "bodyType",
    "body"
   ],
   "properties": {
    "body": {
     "properties": {}
    },
    "type": {
     "type": "string",
     "const": "http"
    },
    "method": {
     "enum": [
      "POST",
      "PUT",
      "PATCH"
     ],
     "type": "string"
    },
    "bodyType": {
     "enum": [
      "json",
      "form-data",
      "text"
     ],
     "type": "string"
    }
   },
   "additionalProperties": false
  }
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/x402-demo-api-quote-endpoint-f2d8fc70/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from x402-demo-api-theta.vercel.app](https://www.zero.xyz/host/x402-demo-api-theta.vercel.app/llms.txt)