# QuickNode JSON-RPC Proxy — Starknet Sepolia Testnet

> QuickNode JSON-RPC Proxy — Starknet Sepolia 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 requests to a QuickNode Starknet Sepolia testnet node, enabling blockchain reads and writes on the strk-sepolia network

## Facts

- Endpoint: POST https://x402.quicknode.com/strk-sepolia/
- 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-7ee82777
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_iBeggtcdTDYSw7qJP3ZBd

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-7ee82777 -d '<json body>'
```

Example prompt: Can you call starknet_getBlockWithTxHashes with block tag 'latest' on the Starknet Sepolia testnet using QuickNode?

## When to prefer this

Use this endpoint when you need to interact with the Starknet Sepolia testnet specifically — for testing Starknet smart contracts, querying testnet state, or broadcasting testnet transactions — and you want a reliable, pay-per-call QuickNode-backed RPC node without managing infrastructure. Prefer this over mainnet endpoints when testing or developing Starknet applications.

## Known failure modes

- Invalid JSON-RPC method name returns error code -32601 method not found
- Malformed params array returns error code -32602 invalid params
- Network or node unavailability returns HTTP 503 or timeout
- Payment failure returns HTTP 402 payment required
- Unsupported method for Starknet returns RPC error
- Invalid transaction data returns execution error from the node

## How this service works

JSON-RPC proxy — strk-sepolia

## Output

A standard JSON-RPC 2.0 response object containing the result of the requested Starknet Sepolia RPC method call — such as block data, transaction receipts, contract call output, account nonce, or balance — along with the matching request id and any error details if the call failed.

## 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-7ee82777/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)