Proxy JSON-RPC Node

`POST` `/api/public/rpc/{chainId}`

Proxies standard JSON-RPC 2.0 requests (such as eth_sendRawTransaction, eth_blockNumber, eth_getTransactionReceipt, eth_call) directly to underlying blockchain nodes with automated upstream health checks, rate distribution, and multi-node fallback rotation.

Request Details

Method: POST
Path: /api/public/rpc/{chainId}
Authentication: Required (Bearer <API_KEY> or x-api-key: <API_KEY>)
Required Scope: read
Compute Cost: 1 CU

Path Parameters

Name	Type	Required	Description
`chainId`	string	Required	EVM Chain ID (e.g. `5042002` for Arc Testnet, `84532` for Base Sepolia, `421614` for Arbitrum Sepolia, `1` for Ethereum Mainnet, or `solana`).

Request Parameters (JSON Body)

Name	Type	Required	Description
`jsonrpc`	string	Required	JSON-RPC specification version (must be `"2.0"`).
`method`	string	Required	Standard RPC method name (e.g. `eth_blockNumber`, `eth_sendRawTransaction`, `eth_getBalance`).
`params`	array	Required	Parameters list required by the specified RPC method.
`id`	integer	Required	Client request identifier echo.

Request Body Example

json
{
  "jsonrpc": "2.0",
  "method": "eth_blockNumber",
  "params": [],
  "id": 1
}

Response Example (`200 OK`)

json
{
  "jsonrpc": "2.0", // JSON-RPC specification version
  "id": 1, // Request identifier echo
  "result": "0x119ffe47" // Hexadecimal block number response
}

Code Examples

cURL (Query Block Number)

bash
curl -X POST "https://tower-devapi.up.railway.app/api/public/rpc/5042002" \
  -H "Authorization: Bearer sk_live_********************" \
  -H "Content-Type: application/json" \
  -d '{
    "jsonrpc": "2.0",
    "method": "eth_blockNumber",
    "params": [],
    "id": 1
  }'

cURL (Broadcast Signed Raw Transaction)

bash
curl -X POST "https://tower-devapi.up.railway.app/api/public/rpc/5042002" \
  -H "Authorization: Bearer sk_live_********************" \
  -H "Content-Type: application/json" \
  -d '{
    "jsonrpc": "2.0",
    "method": "eth_sendRawTransaction",
    "params": ["0x02f873018203e8843b9aca008502540be400825208942de8906a641d65d490bc..."],
    "id": 1
  }'

JavaScript (Fetch)

javascript
const response = await fetch("https://tower-devapi.up.railway.app/api/public/rpc/5042002", {
  method: "POST",
  headers: {
    "Authorization": "Bearer sk_live_********************",
    "Content-Type": "application/json"
  },
  body: JSON.stringify({
    jsonrpc: "2.0",
    method: "eth_blockNumber",
    params: [],
    id: 1
  })
});
const rpcResult = await response.json();
console.log("Current Block Number (hex):", rpcResult.result);

Error Responses

Status Code	Description	Example Payload
`400 Bad Request`	Unsupported `chainId` or invalid JSON-RPC payload structure.	`{"jsonrpc": "2.0", "id": 1, "error": {"code": -32600, "message": "Invalid Request"}}`
`401 Unauthorized`	Missing or invalid Developer API key.	`{"success": false, "error": "Invalid API key"}`
`429 Too Many Requests`	Rate limit quota exceeded.	`{"success": false, "error": "Rate limit exceeded"}`
`502 Bad Gateway`	Upstream blockchain RPC node failed to respond.	`{"success": false, "error": "Failed to reach upstream RPC endpoint"}`