# Multi-Chain RPC Gateway

> Multi-Chain RPC Gateway is a paid API for AI agents from api.eucompliance.tools, paid per call via x402, $0.01/call, status unknown (last checked 2026-09-14).

Routes JSON-RPC calls across Base, Ethereum, Arbitrum, Optimism, and Polygon with automatic node failover and human-readable decoded revert reasons, requiring no API key.

## Facts

- Endpoint: POST https://api.eucompliance.tools/x402/rpc
- Price: $0.01/call
- Payment: x402
- Status: unknown
- Last checked: 2026-09-14
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/multi-chain-rpc-gateway-6769e9ab
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_jUBKHPy63Pp_8JYZ1AAhO

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 multi-chain-rpc-gateway-6769e9ab -d '<json body>'
```

Example prompt: Call eth_call on the USDC contract at 0xA0b86991c6218b36c1d19D4a2e9Eb0cE3606eB48 on Ethereum mainnet with the balanceOf method for address 0xd8dA6BF26964aF9D7eEd9e03E53415D37aA96045 — I need the decoded balance back without setting up my own node or API key.

## When to prefer this

Choose this endpoint when you need multi-chain EVM RPC access without provisioning accounts or API keys on Infura, Alchemy, or similar providers. It is especially valuable when decoded revert reasons are needed for debugging failed transactions, when you want built-in failover across multiple public nodes rather than a single point of failure, or when you want a single endpoint to cover Base, Ethereum, Arbitrum, Optimism, and Polygon. Prefer alternatives if you need WebSocket subscriptions, event streaming, or write methods beyond eth_sendRawTransaction.

## Known failure modes

- All public nodes for the requested chain are throttled or unavailable — returns an error after exhausting the failover list
- Unsupported method requested — only read methods and eth_sendRawTransaction are permitted; other write methods return a rejection
- Batch size exceeds 20 — oversized batches are rejected
- Malformed JSON-RPC payload — returns parse or invalid request error
- Chain not supported — requests for chains other than Base, Ethereum, Arbitrum, Optimism, Polygon return an error
- Payment not received or insufficient — x402 payment of 0.001 USDC not fulfilled results in 402 response

## How this service works

JSON-RPC for Base, Ethereum, Arbitrum, Optimism and Polygon through one endpoint, no account or API key. Automatic failover across several public nodes per chain (the answer names the node that served it), and failed calls come back with Error(string)/Panic(uint256) decoded into plain text. Read methods plus eth_sendRawTransaction; batches up to 20 count as one call. Signed receipt included.

## Output

A standard JSON-RPC 2.0 response object including the result or decoded error. On failure, Error(string) and Panic(uint256) revert reasons are resolved into plain English with a recommended action. The response also names the upstream public node that served the request, and includes a signed receipt confirming the call was processed.

## Request schema (JSON Schema)

```json
{
 "type": "object",
 "properties": {
  "id": {
   "type": [
    "integer",
    "string"
   ]
  },
  "chain": {
   "type": "string",
   "description": "EVM mainnet; defaults to base"
  },
  "method": {
   "type": "string",
   "description": "allowed read-only JSON-RPC method"
  },
  "params": {
   "type": "array"
  },
  "jsonrpc": {
   "enum": [
    "2.0"
   ],
   "type": "string"
  }
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/multi-chain-rpc-gateway-6769e9ab/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from api.eucompliance.tools](https://www.zero.xyz/host/api.eucompliance.tools/llms.txt)