CROSS Chain: Interacting with the Blockchain via JSON-RPC

To interact with CROSS Chain, you need to utilize JSON-RPC to handle transactions with the network. This protocol allows you to send transactions to the CROSS Chain network, retrieve data, and more.

1. What is JSON-RPC?

JSON-RPC is a remote procedure call (RPC) protocol that provides a simple and lightweight way to interact with blockchain networks. The protocol is stateless and can operate across different environments using JSON (RFC 4627) for data formatting. It is flexible and can work over various transport layers like HTTP and sockets.

CROSS Chain implements JSON-RPC to provide developers with access to blockchain data, transaction processing, and other features.

2. CROSS Chain JSON-RPC API Specification

CROSS Chain is fully compatible with the Ethereum JSON-RPC specification. This means any Ethereum-compatible tool can also work with CROSS Chain.

Full spec: Ethereum API Spec

Network Endpoints

Mainnet

https://mainnet.cross-nexus.com

Testnet

https://testnet.cross-nexus.com

3. JSON-RPC Request Structure

Request Format

{
  "jsonrpc": "2.0",
  "method": "method_name",
  "params": [param1, param2],
  "id": 1
}

Response Format

Success:

{
  "jsonrpc": "2.0",
  "id": 1,
  "result": { ... }
}

Error:

{
  "jsonrpc": "2.0",
  "id": 1,
  "error": {
    "code": -32000,
    "message": "Error message",
    "data": "Details"
  }
}

4. Example JSON-RPC Method Calls

4.1 Get Block by Number

{
  "jsonrpc": "2.0",
  "method": "eth_getBlockByNumber",
  "params": ["latest", true],
  "id": 1
}

4.2 Get Transaction by Hash

{
  "jsonrpc": "2.0",
  "method": "eth_getTransactionByHash",
  "params": ["0xd7b510d535e8f107..."],
  "id": 1
}

4.3 Get Account Balance

{
  "jsonrpc": "2.0",
  "method": "eth_getBalance",
  "params": ["0xe5dFec1e7Ca7AA90...", "latest"],
  "id": 1
}

4.4 Send Transaction

{
  "jsonrpc": "2.0",
  "method": "eth_sendTransaction",
  "params": [{
    "from": "0x...",
    "to": "0x...",
    "gas": "0x76c0",
    "gasPrice": "0x9184e72a000",
    "value": "0xde0b6b3a7640000",
    "data": "0x"
  }],
  "id": 1
}

4.5 Smart Contract Call

{
  "jsonrpc": "2.0",
  "method": "eth_call",
  "params": [
    {
      "to": "0x6b175474e89094c44da98b954eedeac495271d0f",
      "data": "0x70a0823100000000..."
    },
    "latest"
  ],
  "id": 1
}

5. Interacting with CROSS Chain using curl

Get Latest Block Number (Mainnet)

curl -X POST https://mainnet.cross-nexus.com \
  -H "Content-Type: application/json" \
  --data '{"jsonrpc":"2.0","method":"eth_blockNumber","params":[],"id":1}'

Get Account Balance (Testnet)

curl -X POST https://testnet.cross-nexus.com \
  -H "Content-Type: application/json" \
  --data '{"jsonrpc":"2.0","method":"eth_getBalance","params":["0x...", "latest"],"id":1}'

6. Commonly Used JSON-RPC Methods

Method	Description
`eth_blockNumber`	Returns the number of the most recent block
`eth_getBalance`	Returns balance of the account at given address
`eth_getBlockByNumber`	Returns information about a block by number
`eth_getBlockByHash`	Returns block info using block hash
`eth_getTransactionCount`	Returns the number of transactions from address
`eth_getTransactionByHash`	Returns transaction details by hash
`eth_getTransactionReceipt`	Returns transaction receipt
`eth_sendRawTransaction`	Submits a raw, signed transaction
`eth_call`	Calls a smart contract function without state changes
`eth_estimateGas`	Estimates gas required for a transaction
`eth_getLogs`	Returns logs based on filter object
`net_version`	Returns current network ID

7. JSON-RPC Error Codes

Code	Message	Description
-32700	Parse error	Invalid JSON
-32600	Invalid Request	The JSON sent is not a valid request
-32601	Method not found	Method does not exist
-32602	Invalid params	Invalid method parameters
-32603	Internal error	Internal JSON-RPC error
-32000 to -32099	Server error	Generic server-side errors

8. Security Considerations

Always use HTTPS when communicating over public networks
Limit API access when exposing nodes to the internet
Perform sensitive operations like private key handling offline
Validate data before sending transactions
Set appropriate gas limits for contract interaction