# QuickNode JSON-RPC Proxy — Sophon Testnet

> QuickNode JSON-RPC Proxy — Sophon Testnet is a paid API for AI agents from x402.quicknode.com, paid per call via x402, $10/call, status unknown (last checked 2026-09-15).

Proxies JSON-RPC calls to the Sophon testnet blockchain node via QuickNode's infrastructure

## Facts

- Endpoint: POST https://x402.quicknode.com/sophon-testnet/
- Price: $10/call
- Payment: x402
- Status: unknown
- Last checked: 2026-09-15
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/quicknode-18a29e2f
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_fsAuZlQ5ND387FodES18U

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 quicknode-18a29e2f -d '<json body>'
```

Example prompt: Call eth_blockNumber on the Sophon testnet to get the current block height, and then use eth_getBlockByNumber to fetch the full details of that block including all transactions.

## When to prefer this

Use this endpoint when you need to interact specifically with the Sophon testnet blockchain — for testing smart contracts, querying testnet state, or developing against Sophon before mainnet deployment. Prefer this over generic RPC providers when you need QuickNode's reliable infrastructure with x402 pay-per-call pricing and no subscription setup.

## Known failure modes

- Invalid JSON-RPC method name returns error code -32601 method not found
- Malformed params array causes -32602 invalid params error
- Payment of $10 USDC not provided results in 402 Payment Required
- Sophon testnet node unavailable returns 503 or upstream error
- Invalid transaction hash or address returns null result
- Rate limiting or quota exceeded returns 429 Too Many Requests

## How this service works

JSON-RPC proxy — sophon-testnet

## Output

A standard JSON-RPC 2.0 response object containing the result field with blockchain data (block info, transaction data, contract return values, balances, etc.) or an error object if the call fails. The response mirrors the Sophon testnet node's native output.

## Request schema (JSON Schema)

```json
{
 "type": "object",
 "required": [
  "jsonrpc",
  "method"
 ],
 "properties": {
  "id": {
   "type": [
    "number",
    "string"
   ],
   "description": "Request identifier"
  },
  "method": {
   "type": "string",
   "description": "JSON-RPC method name (e.g., eth_blockNumber, eth_call)"
  },
  "params": {
   "type": "array",
   "description": "Method parameters"
  },
  "jsonrpc": {
   "type": "string",
   "const": "2.0"
  }
 }
}
```

## Response schema (JSON Schema)

```json
{
 "type": "object",
 "properties": {
  "id": {
   "type": [
    "number",
    "string"
   ]
  },
  "error": {
   "type": "object",
   "properties": {
    "code": {
     "type": "integer"
    },
    "message": {
     "type": "string"
    }
   }
  },
  "result": {
   "description": "RPC result (type varies by method)"
  },
  "jsonrpc": {
   "type": "string",
   "const": "2.0"
  }
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/quicknode-18a29e2f/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from x402.quicknode.com](https://www.zero.xyz/host/x402.quicknode.com/llms.txt)