> ## Documentation Index
> Fetch the complete documentation index at: https://docs.blockops.network/llms.txt
> Use this file to discover all available pages before exploring further.

# Common RPC methods & examples

> Common JSON-RPC methods, with cURL, wscat and @polkadot/api examples.

### Common EVM RPC Methods

Once your endpoints are generated, you can interact with the network using standard JSON-RPC methods. Here is a quick reference for the most common methods you will use when building your project:

| Category                 | Method                      | Description                                                                                |
| :----------------------- | :-------------------------- | :----------------------------------------------------------------------------------------- |
| **Account Info**         | `eth_getBalance`            | Returns the native token balance of an address (e.g., LSK or ETH).                         |
|                          | `eth_getTransactionCount`   | Returns the nonce of an account (essential for sending transactions).                      |
| **Chain State**          | `eth_chainId`               | Returns the specific Chain ID (e.g., Lisk Mainnet is 1135).                                |
|                          | `eth_gasPrice`              | Returns the current price of gas on the network in wei.                                    |
| **Transaction Info**     | `eth_getTransactionByHash`  | Gets the full details of a transaction using its unique hash.                              |
|                          | `eth_getTransactionReceipt` | Gets the receipt (status, logs, gas used) of a transaction.                                |
| **Contract Interaction** | `eth_call`                  | Executes a "read-only" call to a smart contract (costs zero gas).                          |
|                          | `eth_estimateGas`           | Estimates how much gas a transaction will cost before you send it.                         |
| **Events & Logs**        | `eth_getLogs`               | Returns an array of all logs matching a specific filter (highly useful for indexing data). |

### Practical Examples

**Connect via a command line**

You can connect to the network using WebSocket or HTTP with your API key in two ways:

* Adding the API key as a query string `?api_key=${APIKEY}`
* Or the request header `-H 'authorization: APIKEY ${APIKEY}'`

**cURL**

For example, the following cURL command can be used to get the header and body of a block.

`curl -H "Content-Type: application/json" -H "authorization: APIKEY xxxx" -d '{"id":1, "jsonrpc":"2.0", "method": "eth_getBlockByNumber", "params": ["latest", true]}' https://lisk.rpc.blockops.network/rpc`

**What Success Looks Like:**
Here is the successful JSON response you will receive back, proving your app is communicating with the chain:

`{"jsonrpc":"2.0","result":{"hash":"0x381dd358f0b1e328e861822b2a51a72e8dc064803a5c7ccc96277da3b16d7667","number":"0xe07a1d", "timestamp": "0x65123abc"},"id":1}`

**wscat**

If you want to send data requests with WebSockets, you can use several libraries or wscat. You can install and use wscat as follows:

* Download wscat from [https://www.npmjs.com/package/wscat](https://www.npmjs.com/package/wscat)
* Install wscat by running the following command: `npm install -g wscat`

You can connect to the network with wscat using two options. With the request header:

`wscat -c 'wss://lisk.rpc.blockops.network/ws' --header 'authorization: APIKEY xxxx'`

Or by adding the API key as a query string:

`wscat -c 'wss://lisk.rpc.blockops.network/ws?api_key=**********************'`

After executing the command, the terminal will display a message indicating that the connection has been enabled successfully:

`Connected (press CTRL+C to quit)`

Then, you can send the following request into the open terminal:

`> {"id":1, "jsonrpc":"2.0", "method": "eth_blockNumber"}`

<Frame caption="Response from network node">
  <img src="https://mintcdn.com/blockops-3855c227/OGmnNOc7FURsTCyJ/images/image-22.png?fit=max&auto=format&n=OGmnNOc7FURsTCyJ&q=85&s=587ab4cb0232156faf681246179ba99c" alt="" width="712" height="236" data-path="images/image-22.png" />
</Frame>

### Connect via Polkadot JS API

If you are building on Polkadot or any Substrate-based chain, you can connect your application using the official `@polkadot/api` library.

First, install the library in your project repository:

```bash theme={null}
npm install @polkadot/api
```

Then, instantiate the `WsProvider` using your Blockops WSS endpoint. The most reliable way to authenticate is by appending your API key as a query parameter in the URL.

```javascript theme={null}
import { ApiPromise, WsProvider } from "@polkadot/api";

async function connectToBlockops() {
  const WSS_URL = "wss://polkadot.rpc.blockops.network/ws?api_key=YOUR_API_KEY";

  const wsProvider = new WsProvider(WSS_URL);

  try {
    const api = await ApiPromise.create({ provider: wsProvider });

    const chain = await api.rpc.system.chain();
    const lastHeader = await api.rpc.chain.getHeader();

    console.log(`Successfully connected to ${chain}!`);
    console.log(`Latest Block Number: ${lastHeader.number.toHuman()}`);
  } catch (error) {
    console.error("Connection failed:", error);
  }
}

connectToBlockops();
```