# BlockRun.AI Multi-Chain JSON-RPC (Base)

> BlockRun.AI Multi-Chain JSON-RPC (Base) is a paid API for AI agents from blockrun.ai, paid per call via x402, $0.003/call, status unknown (last checked 2026-10-13).

Proxies JSON-RPC calls to the Base blockchain network via Tatum's gateway, accepting pay-per-call in USDC with no API key required.

## Facts

- Endpoint: POST https://blockrun.ai/api/v1/rpc/base?utm_source=zero.xyz
- Price: $0.003/call
- Payment: x402
- Status: unknown
- Last checked: 2026-10-13
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/blockrun-ai-multi-chain-json-rpc-base-58adfecb
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_cXDPQrmZJ0FpCKnoJfP2h

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 blockrun-ai-multi-chain-json-rpc-base-58adfecb -d '<json body>'
```

Example prompt: Check the current ETH balance for address 0xd8dA6BF26964aF9D7eEd9e03E53415D37aA96045 on Base — send eth_getBalance with the address and 'latest' as params.

## When to prefer this

Choose this endpoint when you need to query the Base blockchain specifically, want a no-API-key pay-per-call model billed in USDC, or are building an AI agent that needs ad-hoc on-chain reads without managing RPC subscriptions or API credentials. Ideal for lightweight, infrequent blockchain queries where provisioning a dedicated RPC node or API key is impractical.

## Known failure modes

- Invalid JSON-RPC method name returns error code -32601
- Malformed params array returns error code -32602
- Insufficient USDC payment triggers HTTP 402
- Rate limiting or gateway timeout from Tatum returns HTTP 503
- Calling non-EVM methods (e.g. Solana getSlot) on the Base endpoint returns an error

## How this service works

Multi-chain JSON-RPC passthrough fronted by BlockRun, powered by Tatum's gateway across 40 chains (Ethereum, Base, Solana, Polygon, BSC, Arbitrum, Optimism, Avalanche, Bitcoin, Sui, and more). One endpoint, every chain, pay-per-call in USDC, no API key. $0.002 per call (or per element of a JSON-RPC batch). Network: Base.

## Output

Returns a standard JSON-RPC 2.0 response object containing the 'result' field with chain-specific data (e.g. hex-encoded balance, block number, transaction receipt object, contract return value) or an 'error' object with code and message if the call fails.

## Request schema (JSON Schema)

```json
{
 "type": "object",
 "properties": {
  "id": {
   "type": [
    "string",
    "number"
   ],
   "description": "JSON-RPC id"
  },
  "method": {
   "type": "string",
   "description": "Chain RPC method, e.g. eth_blockNumber, eth_call, eth_getBalance (EVM) or getSlot, getAccountInfo (Solana)."
  },
  "params": {
   "type": "array",
   "description": "Method-specific params."
  },
  "jsonrpc": {
   "type": "string",
   "description": "\"2.0\""
  }
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/blockrun-ai-multi-chain-json-rpc-base-58adfecb/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from blockrun.ai](https://www.zero.xyz/host/blockrun.ai/llms.txt)