# QuantaFlow x402 API Gateway — Alchemy Ethereum Sepolia

> QuantaFlow x402 API Gateway — Alchemy Ethereum Sepolia is a paid API for AI agents from quanta-roan.vercel.app, paid per call via x402, $0.01/call, status unknown (last checked 2026-09-13).

Proxies requests to Alchemy's Ethereum Sepolia testnet RPC/API endpoint via x402 micropayment-gated passthrough, charging $0.01 USDC per call

## Facts

- Endpoint: POST https://quanta-roan.vercel.app/api/service/alchemy-eth-sepolia
- Price: $0.01/call
- Payment: x402
- Status: unknown
- Last checked: 2026-09-13
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/quantaflow-x402-api-gateway-alchemy-ethereum-sepolia-39516e3c
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_QwLLic_pRK3dIzOS58ZPY

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 quantaflow-x402-api-gateway-alchemy-ethereum-sepolia-39516e3c -d '<json body>'
```

Example prompt: Query the Alchemy Ethereum Sepolia testnet for the latest block number — use the eth_blockNumber RPC method and pay the per-call fee automatically.

## When to prefer this

Choose this endpoint when you need pay-per-call, keyless access to Alchemy's Ethereum Sepolia testnet RPC without managing an Alchemy account or API key — ideal for AI agents that need to make occasional blockchain queries on the Sepolia testnet and want to pay via x402 USDC micropayments rather than maintain API key credentials.

## Known failure modes

- Payment failure: insufficient USDC balance or invalid x402 payment header returns 402 Payment Required
- Invalid path: unrecognized Alchemy API path returns upstream 404 or error
- Malformed JSON body: invalid JSON in body field causes upstream RPC error
- Alchemy upstream outage: returns 502 or 503 if Alchemy Sepolia node is unavailable
- Unsupported RPC method: Alchemy may reject unsupported or disabled JSON-RPC methods with an error response

## How this service works

Every request, a quantum of value. x402 protocol-based payment endpoint for web3/DeFi tools.

## Output

The raw upstream response from Alchemy's Ethereum Sepolia API is passed through directly — typically a JSON-RPC response object containing the requested blockchain data (block info, transaction details, account balances, etc.) along with the appropriate content-type header. No transformation is applied.

## Request schema (JSON Schema)

```json
{
 "type": "object",
 "properties": {
  "body": {
   "type": "string",
   "description": "Optional JSON body forwarded to POST requests."
  },
  "path": {
   "type": "string",
   "description": "Path below the selected upstream origin."
  },
  "query": {
   "type": "object"
  },
  "method": {
   "enum": [
    "GET",
    "POST"
   ],
   "type": "string"
  }
 }
}
```

## Response schema (JSON Schema)

```json
{
 "description": "The upstream response body and content type are passed through after successful payment."
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/quantaflow-x402-api-gateway-alchemy-ethereum-sepolia-39516e3c/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from quanta-roan.vercel.app](https://www.zero.xyz/host/quanta-roan.vercel.app/llms.txt)