# QuickNode JSON-RPC Proxy — Mantle Sepolia

> QuickNode JSON-RPC Proxy — Mantle Sepolia 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 Mantle Sepolia testnet via QuickNode's infrastructure, enabling blockchain reads and writes over a pay-per-call x402 payment model.

## Facts

- Endpoint: POST https://x402.quicknode.com/mantle-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-ab59bf08
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_u5VKzSvUC34l-Ym1FhhLL

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-ab59bf08 -d '<json body>'
```

Example prompt: Call eth_blockNumber on the Mantle Sepolia testnet to get the latest block height — use JSON-RPC 2.0 with an empty params array and request ID 1.

## When to prefer this

Use this endpoint when you need to interact with the Mantle Sepolia testnet specifically — for testing Mantle Layer 2 smart contracts, checking testnet state, or broadcasting test transactions without using real funds. Prefer this over general Ethereum RPC endpoints when your target is the Mantle L2 environment, and over the Mantle mainnet endpoint when you want a risk-free testnet environment.

## Known failure modes

- Invalid JSON-RPC method name returns error code -32601 (method not found)
- Malformed params array returns error code -32602 (invalid params)
- Payment failure or insufficient USDC balance blocks the request with a 402 response
- Network or node downtime on Mantle Sepolia returns a 5xx or timeout error
- Calling mainnet-only methods on a testnet returns an unsupported method error

## How this service works

JSON-RPC proxy — mantle-sepolia

## Output

Returns a standard JSON-RPC 2.0 response object containing the result of the requested method (e.g., block number as a hex string, transaction data as an object, contract call 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-ab59bf08/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)