# QuickNode JSON-RPC Proxy — ARC Testnet

> QuickNode JSON-RPC Proxy — ARC Testnet is a paid API for AI agents from x402.quicknode.com, paid per call via x402, $10/call, status unknown (last checked 2026-09-14).

Proxies JSON-RPC calls to the ARC testnet blockchain, enabling agents to query chain state, submit transactions, and interact with smart contracts on ARC testnet.

## Facts

- Endpoint: POST https://x402.quicknode.com/arc-testnet/
- Price: $10/call
- Payment: x402
- Status: unknown
- Last checked: 2026-09-14
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/quicknode-29378d81
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_CN2UHYk1PJBd1OWdAFZEi

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-29378d81 -d '<json body>'
```

Example prompt: Can you call eth_blockNumber on the ARC testnet using QuickNode's RPC proxy and tell me the latest block height?

## When to prefer this

Choose this endpoint when you need to interact specifically with the ARC testnet blockchain via standard JSON-RPC. Prefer this over other QuickNode endpoints when your dApp, test suite, or agent workflow targets ARC testnet specifically. Use for development and testing workflows that require ARC testnet access without managing your own node infrastructure.

## Known failure modes

- Invalid JSON-RPC method name returns error code -32601 (method not found)
- Malformed params array causes -32602 (invalid params) error
- Network or node unavailability returns 503 or timeout
- Payment failure (insufficient USDC or x402 protocol error) blocks the request
- Calling mainnet-only methods on testnet may return unsupported errors

## How this service works

JSON-RPC proxy — arc-testnet

## Output

Returns a standard JSON-RPC 2.0 response object containing the result field with the requested blockchain data (e.g. block number, transaction receipt, contract return value), or an error object with code and message if the call fails.

## 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-29378d81/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)