# QuickNode JSON-RPC Proxy — Flare Coston2 Testnet

> QuickNode JSON-RPC Proxy — Flare Coston2 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 Flare Coston2 testnet blockchain, enabling reads and writes via standard Ethereum-compatible methods.

## Facts

- Endpoint: POST https://x402.quicknode.com/flare-coston2/
- 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-0f04900d
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_UaT7pofJ-RVcxJDPzuhvZ

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-0f04900d -d '<json body>'
```

Example prompt: Call eth_blockNumber on the Flare Coston2 testnet using QuickNode's JSON-RPC proxy to get the latest block number.

## When to prefer this

Use this endpoint when you need to interact with the Flare Coston2 testnet specifically — for testing Flare smart contracts, FTSO (Flare Time Series Oracle) integrations, or EVM-compatible dApps before mainnet deployment. Prefer this over generic Ethereum RPC endpoints when your target chain is Flare Coston2.

## 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 congestion or node unavailability returns HTTP 503 or JSON-RPC internal error -32603
- Payment failure or insufficient USDC balance returns HTTP 402 Payment Required
- Rate limiting or quota exceeded returns HTTP 429

## How this service works

JSON-RPC proxy — flare-coston2

## Output

Returns a standard JSON-RPC 2.0 response object containing a result field with the method's return value (e.g. block number as hex, account balance in wei, transaction receipt object) or an error object 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-0f04900d/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)