# v0-x402-payments-demo Premium Alpha Feed

> v0-x402-payments-demo Premium Alpha Feed is a paid API for AI agents from v0-x402-payments-demo.vercel.app, paid per call via x402, $0.01/call, status down (last checked 2026-09-14).

Returns curated on-chain alpha including yield venues, mempool anomalies, and replayable agent trade intents, gated by a $0.01 USDC x402 micropayment.

## Facts

- Endpoint: GET https://v0-x402-payments-demo.vercel.app/api/premium
- Price: $0.01/call
- Payment: x402
- Status: down
- Last checked: 2026-09-14
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/v0-x402-payments-demo-vercel-app-a7c0686a
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_Kh1s8qKr2a6owUI3IpUME

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 v0-x402-payments-demo-vercel-app-a7c0686a
```

Example prompt: Fetch me the latest on-chain alpha — yield venues, mempool anomalies, and any replayable trade intents — paying 0.01 USDC via the x402 micropayment protocol.

## When to prefer this

Use this endpoint when an AI agent needs live, curated on-chain intelligence — specifically yield venue discovery, mempool anomaly alerts, or tradeable agent intents — and is capable of executing x402 micropayments in USDC on Base. Prefer this over general blockchain explorers or free-tier data feeds when you need pre-curated, actionable alpha rather than raw chain data.

## Known failure modes

- Missing X-PAYMENT header returns 402 with error 'X-PAYMENT header is required' and accepts array listing USDC on Base
- Insufficient payment amount causes rejection with maxAmountRequired mismatch
- Expired payment timeout (maxTimeoutSeconds: 60) causes payment to be rejected
- Invalid USDC asset address or wrong network (not Base) causes payment failure
- Malformed currency or paymentAmount fields cause request rejection

## How this service works

Premium alpha — Curated on-chain alpha: yield venues, mempool anomalies, and replayable agent trade intents.

## Output

A JSON payload containing curated on-chain alpha: yield venues currently offering attractive returns, detected mempool anomalies, and replayable agent trade intents, along with x402 payment metadata confirming the transaction was accepted.

## Request schema (JSON Schema)

```json
{
 "type": "object",
 "required": [
  "currency",
  "endpoint",
  "paymentAmount"
 ],
 "properties": {
  "currency": {
   "type": "string"
  },
  "endpoint": {
   "type": "string"
  },
  "paymentAmount": {
   "type": "string"
  }
 }
}
```

## Response schema (JSON Schema)

```json
{
 "type": "object",
 "required": [
  "_x402",
  "error",
  "accepts",
  "x402Version",
  "_paymentRequired",
  "_wwwAuthenticate"
 ],
 "properties": {
  "_x402": {
   "type": "boolean"
  },
  "error": {
   "type": "string"
  },
  "accepts": {
   "type": "array",
   "items": {
    "type": "object",
    "required": [
     "asset",
     "extra",
     "payTo",
     "scheme",
     "network",
     "mimeType",
     "resource",
     "description",
     "outputSchema",
     "maxAmountRequired",
     "maxTimeoutSeconds"
    ],
    "properties": {
     "asset": {
      "type": "string"
     },
     "extra": {
      "type": "object",
      "required": [
       "name",
       "version"
      ],
      "properties": {
       "name": {
        "type": "string"
       },
       "version": {
        "type": "string"
       }
      }
     },
     "payTo": {
      "type": "string"
     },
     "scheme": {
      "type": "string"
     },
     "network": {
      "type": "string"
     },
     "mimeType": {
      "type": "string"
     },
     "resource": {
      "type": "string"
     },
     "description": {
      "type": "string"
     },
     "outputSchema": {
      "type": "object",
      "required": [
       "input"
      ],
      "properties": {
       "input": {
        "type": "object",
        "required": [
         "type",
         "method",
         "discoverable"
        ],
        "properties": {
         "type": {
          "type": "string"
         },
         "method": {
          "type": "string"
         },
         "discoverable": {
          "type": "boolean"
         }
        }
       }
      }
     },
     "maxAmountRequired": {
      "type": "string"
     },
     "maxTimeoutSeconds": {
      "type": "number"
     }
    }
   }
  },
  "x402Version": {
   "type": "number"
  },
  "_paymentRequired": {
   "type": "boolean"
  },
  "_wwwAuthenticate": {
   "type": "null"
  }
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/v0-x402-payments-demo-vercel-app-a7c0686a/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from v0-x402-payments-demo.vercel.app](https://www.zero.xyz/host/v0-x402-payments-demo.vercel.app/llms.txt)