# QuantaFlow x402 API Gateway — Alchemy Stable Mainnet

> QuantaFlow x402 API Gateway — Alchemy Stable Mainnet is a paid API for AI agents from quanta-roan.vercel.app, paid per call via x402, $0.01/call, status unknown (last checked 2026-10-23).

Proxies POST requests to the Alchemy stable mainnet endpoint via the x402 micropayment protocol, charging $0.01 USDC per call.

## Facts

- Endpoint: POST https://quanta-roan.vercel.app/api/service/alchemy-stable-mainnet?utm_source=zero.xyz
- Price: $0.01/call
- Payment: x402
- Status: unknown
- Last checked: 2026-10-23
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/quantaflow-x402-api-gateway-alchemy-stable-mainnet-16fd9edc
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_2aXEhyXL5QfrdFEb0DEPX

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-stable-mainnet-16fd9edc -d '<json body>'
```

Example prompt: Forward a request to the Alchemy stable mainnet at path /v2/eth_blockNumber with no body — use the QuantaFlow x402 gateway so it automatically handles the $0.01 USDC payment.

## When to prefer this

Choose this endpoint when you need pay-as-you-go access to Alchemy's stable Ethereum mainnet API without committing to a monthly subscription, especially in agent workflows where call volume is unpredictable. It is ideal for web3 agents using the x402 micropayment protocol to autonomously authorize per-call USDC fees. Prefer it over a direct Alchemy subscription for low-volume or bursty on-chain queries.

## Known failure modes

- Payment failure — insufficient USDC balance or invalid x402 payment header returns 402 Payment Required
- Invalid path — unrecognized or malformed upstream path returns an error from Alchemy or the gateway
- Alchemy upstream error — Alchemy may return RPC errors (e.g. invalid params, method not found) passed through as-is
- Rate limiting — Alchemy upstream quota exceeded
- Network timeout — upstream Alchemy node takes too long to respond

## How this service works

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

## Output

The raw response body and content type returned by the Alchemy stable mainnet upstream are passed through unchanged after successful x402 payment verification. Typically a JSON-RPC result containing blockchain data such as block numbers, balances, or transaction receipts.

## 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-stable-mainnet-16fd9edc/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)