# fold · x402 — Onchain JSON-RPC Gateway

> fold · x402 — Onchain JSON-RPC Gateway is a paid API for AI agents from x402.fold.computer, paid per call via x402, $0.001/call, status down (last checked 2026-09-15).

Executes read-only JSON-RPC calls (e.g. eth_getBalance) against EVM-compatible chains, returning machine-readable onchain data for agents, priced per call via x402.

## Facts

- Endpoint: POST https://x402.fold.computer/rpc
- Price: $0.001/call
- Payment: x402
- Status: down
- Last checked: 2026-09-15
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/fold-x402-onchain-json-rpc-gateway-8fb5009b
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_1O-oXFGr6uLyidiNUBR5N

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 fold-x402-onchain-json-rpc-gateway-8fb5009b -d '<json body>'
```

Example prompt: Check the ETH balance of address 0xd8dA6BF26964aF9D7eEd9e03E53415D37aA96045 on Base using eth_getBalance — I need the current onchain balance right now.

## When to prefer this

Use this endpoint when an AI agent needs to make read-only JSON-RPC calls against major EVM chains (Base, Ethereum, Arbitrum, Optimism, Polygon) and wants to pay per call via the x402 micropayment protocol. Prefer this over self-hosted RPC nodes when you want zero infrastructure setup and onchain micropayment billing.

## Known failure modes

- Unsupported chain name → likely 400 or error status
- Invalid or non-read-only JSON-RPC method → error or rejected request
- Malformed params array → RPC execution error
- Payment failure (x402) → 402 response, call not executed
- Node unavailable for chain → upstream RPC timeout or error

## How this service works

Machine-readable market intelligence for onchain agents, served over x402.

## Output

A JSON object with a 'status' field and a 'data' object containing the result of the JSON-RPC call, which may include fields like title, url, publishedDate, and highlights depending on the method called.

## Request schema (JSON Schema)

```json
{
 "type": "object",
 "required": [
  "chain",
  "method"
 ],
 "properties": {
  "chain": {
   "type": "string",
   "description": "base, ethereum, arbitrum, optimism, polygon"
  },
  "method": {
   "type": "string",
   "description": "read-only JSON-RPC method, e.g. eth_getBalance"
  },
  "params": {
   "type": "array",
   "description": "JSON-RPC params"
  }
 }
}
```

## Response schema (JSON Schema)

```json
{
 "type": "object",
 "required": [
  "status",
  "data"
 ],
 "properties": {
  "data": {
   "type": "object",
   "description": "results: title, url, publishedDate, highlights"
  },
  "status": {
   "type": "string"
  }
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/fold-x402-onchain-json-rpc-gateway-8fb5009b/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from x402.fold.computer](https://www.zero.xyz/host/x402.fold.computer/llms.txt)