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

<AgentInstructions>

## Submitting Feedback

If you encounter incorrect, outdated, or confusing documentation on this page, submit feedback:

POST https://docs.chainstack.com/feedback

```json
{
  "path": "/docs/optimism-tooling",
  "feedback": "Description of the issue"
}
```

Only submit feedback when you have something specific and actionable to report.

</AgentInstructions>

# Optimism tooling

> Complete Optimism tooling guide for Chainstack nodes. Use MetaMask, Hardhat, web3.js, ethers.js, Foundry, GraphQL, and more to build dApps on Optimism Layer 2.

Get started with a [reliable Optimism RPC endpoint](https://chainstack.com/build-better-with-optimism/) to use the tools below.

## MetaMask

On the [node access page](/docs/manage-your-node#view-node-access-and-credentials), click **Connect wallet**.

## Hardhat

Configure [Hardhat](https://hardhat.org/) to deploy contracts and interact through your Optimism nodes.

1. Install [Hardhat](https://hardhat.org/) and create a project.

2. Create a new environment in `hardhat.config.js`:

   <CodeGroup>
     ```javascript Javascript theme={"system"}
     require("@nomiclabs/hardhat-waffle");
     ...
     module.exports = {
       solidity: "0.7.3",
       networks: {
         chainstack: {
             url: "YOUR_CHAINSTACK_ENDPOINT",
             accounts: ["YOUR_PRIVATE_KEY"]
         },
       }
     };
     ```
   </CodeGroup>

   where

   * YOUR\_CHAINSTACK\_ENDPOINT — your node HTTPS or WSS endpoint protected either with the key or password. See [node access details](/docs/manage-your-node#view-node-access-and-credentials).
   * YOUR\_PRIVATE\_KEY — the private key of the account that you use to deploy the contract

3. Run `npx hardhat run scripts/deploy.js --network chainstack` and Hardhat will deploy using Chainstack.

See also [Forking EVM-compatible mainnet with Hardhat](https://support.chainstack.com/hc/en-us/articles/900004242406).

## Remix IDE

To make Remix IDE interact with the network through a Chainstack node:

1. Get [MetaMask](https://metamask.io/) and set it to interact through a Chainstack node. See [Interacting through MetaMask](#metamask).
2. In Remix IDE, navigate to the **Deploy** tab. Select **Injected Provider - MetaMask** in **Environment**.

This will engage MetaMask and make Remix IDE interact with the network through a Chainstack node.

## web3.js

Build DApps using [web3.js](https://github.com/ethereum/web3.js/) and Polygon nodes deployed with Chainstack.

1. Install [web3.js](https://web3js.readthedocs.io/).
2. Connect over HTTP or WebSocket.

### HTTP

Use the `HttpProvider` object to connect to your node HTTPS endpoint and get the latest block number:

<CodeGroup>
  ```javascript Javascript theme={"system"}
  const Web3 = require('web3');

  const web3 = new Web3(new Web3.providers.HttpProvider('YOUR_CHAINSTACK_ENDPOINT'));

  web3.eth.getBlockNumber().then(console.log);
  ```
</CodeGroup>

where YOUR\_CHAINSTACK\_ENDPOINT is your node HTTPS endpoint protected either with the key or password.

### WebSocket

Use the `WebsocketProvider` object to connect to your node WSS endpoint and get the latest block number:

<CodeGroup>
  ```javascript Javascript theme={"system"}
  const Web3 = require('web3');

  const web3 = new Web3(new Web3.providers.WebsocketProvider('YOUR_CHAINSTACK_ENDPOINT'));

  web3.eth.getBlockNumber().then(console.log);
  ```
</CodeGroup>

where YOUR\_CHAINSTACK\_ENDPOINT is your node WSS endpoint protected either with the key or password.

## web3.py

Build DApps using [web3.py](https://github.com/ethereum/web3.py) and Optimism nodes deployed with Chainstack.

1. Install [web3.py](https://web3py.readthedocs.io/).
2. Connect over HTTP or WebSocket. See also [EVM node connection: HTTP vs WebSocket](https://support.chainstack.com/hc/en-us/articles/900002187586-Ethereum-node-connection-HTTP-vs-WebSocket).

### HTTP

Use the `HTTPProvider` to connect to your node endpoint and get the latest block number.

<CodeGroup>
  ```python Key Protected theme={"system"}
  from web3 import Web3

  web3 = Web3(Web3.HTTPProvider('YOUR_CHAINSTACK_ENDPOINT'))
  print(web3.eth.block_number)
  ```

  ```python Password Protected theme={"system"}
  from web3 import Web3

  web3 = Web3(Web3.HTTPProvider('https://%s:%s@%s'% ("USERNAME", "PASSWORD", "HOSTNAME")))
  print(web3.eth.block_number)
  ```
</CodeGroup>

where

* YOUR\_CHAINSTACK\_ENDPOINT — your node HTTPS endpoint protected either with the key or password
* HOSTNAME — your node HTTPS endpoint hostname
* USERNAME — your node access username (for password-protected endpoints)
* PASSWORD — your node access password (for password-protected endpoints)

See also [node access details](/docs/manage-your-node#view-node-access-and-credentials).

### WebSocket

Use the `WebsocketProvider` object to connect to your node WSS endpoint and get the latest block number.

<CodeGroup>
  ```python Key Protected theme={"system"}
  from web3 import Web3

  web3 = Web3(Web3.WebsocketProvider('YOUR_CHAINSTACK_ENDPOINT'))
  print(web3.eth.block_number)
  ```

  ```python Password Protected theme={"system"}
  from web3 import Web3

  web3 = Web3(Web3.WebsocketProvider('wss://%s:%s@%s'% ("USERNAME", "PASSWORD", "HOSTNAME")))
  print(web3.eth.block_number)
  ```
</CodeGroup>

where

* YOUR\_CHAINSTACK\_ENDPOINT — your node WSS endpoint protected either with the key or password
* HOSTNAME — your node WSS endpoint hostname
* USERNAME — your node access username (for password-protected endpoints)
* PASSWORD — your node access password (for password-protected endpoints)

See also [WebSocket connection to an EVM node](https://support.chainstack.com/hc/en-us/articles/900001918763-WebSocket-connection-to-an-Ethereum-node).

## web3.php

Build DApps using [web3.php](https://github.com/web3p/web3.php) and Optimism nodes deployed with Chainstack.

1. Install [web3.php](https://github.com/web3p/web3.php).

2. Connect over HTTP:

   <CodeGroup>
     ```php Php theme={"system"}
      <?php

      require_once "vendor/autoload.php";

      use Web3\Web3;
      use Web3\Providers\HttpProvider;
      use Web3\RequestManagers\HttpRequestManager;

      $web3 = new Web3(new HttpProvider(new HttpRequestManager("YOUR_CHAINSTACK_ENDPOINT", 5)));
      ?>
     ```
   </CodeGroup>

   where YOUR\_CHAINSTACK\_ENDPOINT is your node HTTPS endpoint protected either with the key or password

3. Use [JSON-RPC methods](https://eth.wiki/json-rpc/API) to interact with the node.

   Example to get the latest block number:

   <CodeGroup>
     ```php Php theme={"system"}
     <?php

     require_once "vendor/autoload.php";

     use Web3\Web3;
     use Web3\Providers\HttpProvider;
     use Web3\RequestManagers\HttpRequestManager;

     $web3 = new Web3(new HttpProvider(new HttpRequestManager("YOUR_CHAINSTACK_ENDPOINT", 5)));

     $eth = $web3->eth;

     $eth->blockNumber(function ($err, $data) {
          print "$data \n";
     });
     ?>
     ```
   </CodeGroup>

## web3j

Build DApps using [web3j](https://github.com/web3j/web3j) and Optimism nodes deployed with Chainstack.

Use the `HttpService` object to connect to your node endpoint.

Example to get the latest block number:

<CodeGroup>
  ```java Java theme={"system"}
  package getLatestBlock;

  import java.io.IOException;
  import java.util.logging.Level;
  import java.util.logging.Logger;

  import org.web3j.protocol.Web3j;
  import org.web3j.protocol.core.DefaultBlockParameterName;
  import org.web3j.protocol.core.methods.response.EthBlock;
  import org.web3j.protocol.exceptions.ClientConnectionException;
  import org.web3j.protocol.http.HttpService;

  import okhttp3.Authenticator;
  import okhttp3.Credentials;
  import okhttp3.OkHttpClient;
  import okhttp3.Request;
  import okhttp3.Response;
  import okhttp3.Route;

  public final class App {

    private static final String USERNAME = "USERNAME";
    private static final String PASSWORD = "PASSWORD";
    private static final String ENDPOINT = "ENDPOINT";

    public static void main(String[] args) {
      try {

        OkHttpClient.Builder clientBuilder = new OkHttpClient.Builder();
        clientBuilder.authenticator(new Authenticator() {
            @Override public Request authenticate(Route route, Response response) throws IOException {
                String credential = Credentials.basic(USERNAME, PASSWORD);
                return response.request().newBuilder().header("Authorization", credential).build();
            }
        });

        HttpService service = new HttpService(RPC_ENDPOINT, clientBuilder.build(), false);
        Web3j web3 = Web3j.build(service);

        EthBlock.Block latestBlock = web3.ethGetBlockByNumber(DefaultBlockParameterName.LATEST, false).send().getBlock();

        System.out.println("Latest Block: #" + latestBlock.getNumber());

      } catch (IOException | ClientConnectionException ex) {

        Logger.getLogger(App.class.getName()).log(Level.SEVERE, null, ex);
      }
    }

  }
  ```
</CodeGroup>

where

* ENDPOINT — your node HTTPS endpoint
* USERNAME — your node access username
* PASSWORD — your node access password

See also [the full code on GitHub](https://github.com/chainstack/web3j-getLatestBlock).

## ethers.js

Build DApps using [ethers.js](https://github.com/ethers-io/ethers.js/) and Optimism nodes deployed with Chainstack.

1. Install [ethers.js](https://www.npmjs.com/package/ethers).
2. Connect over HTTP or WebSocket. See also [EVM node connection: HTTP vs WebSocket](https://support.chainstack.com/hc/en-us/articles/900002187586-Ethereum-node-connection-HTTP-vs-WebSocket).

### HTTP

Use the `JsonRpcProvider` object to connect to your node endpoint and get the latest block number:

<CodeGroup>
  ```javascript Key Protected theme={"system"}
  const { ethers } = require("ethers");

  var urlInfo = {
      url: 'YOUR_CHAINSTACK_ENDPOINT'
  };
  var provider = new ethers.providers.JsonRpcProvider(urlInfo, NETWORK_ID);

  provider.getBlockNumber().then(console.log);
  ```

  ```javascript Password Protected theme={"system"}
  const { ethers } = require("ethers");

  var urlInfo = {
      url: 'YOUR_CHAINSTACK_ENDPOINT',
      user: 'USERNAME',
      password: 'PASSWORD'
  };
  var provider = new ethers.providers.JsonRpcProvider(urlInfo, NETWORK_ID);

  provider.getBlockNumber().then(console.log);
  ```
</CodeGroup>

where

* YOUR\_CHAINSTACK\_ENDPOINT — your node HTTPS endpoint protected either with the key or password

* USERNAME — your node access username (for password-protected endpoints)

* PASSWORD — your node access password (for password-protected endpoints)

* NETWORK\_ID — Optimism network ID:

  * Mainnet: `10`
  * Testnet: `420`

See [node access details](/docs/manage-your-node#view-node-access-and-credentials).

### WebSocket

Use the `WebSocketProvider` object to connect to your node WSS endpoint and get the latest block number:

<CodeGroup>
  ```javascript Javascript theme={"system"}
  const { ethers } = require("ethers");

  const provider = new ethers.providers.WebSocketProvider('YOUR_CHAINSTACK_ENDPOINT', NETWORK_ID);

  provider.getBlockNumber().then(console.log);
  ```
</CodeGroup>

where

* YOUR\_CHAINSTACK\_ENDPOINT — your node HTTPS endpoint protected either with the key or password

* USERNAME — your node access username (for password-protected endpoints)

* PASSWORD — your node access password (for password-protected endpoints)

* NETWORK\_ID — Optimism network ID:

  * Mainnet: `10`
  * Testnet: `420`

See [node access details](/docs/manage-your-node#view-node-access-and-credentials).

## Brownie

1. Install [Brownie](https://eth-brownie.readthedocs.io/en/stable/install.html).
2. Use the `brownie networks add` command with the node endpoint:

<CodeGroup>
  ```shell Shell theme={"system"}
  brownie networks add Optimism ID name="NETWORK_NAME" host= YOUR_CHAINSTACK_ENDPOINT chainid=NETWORK_ID
  ```
</CodeGroup>

where

* ID — any name that you will use as the network tag to run a deployment. For example, `optimism-testnet`.

* NETWORK\_NAME — any name that you want to identify the network by in the list of networks. For example, **Testnet (Chainstack)**.

* YOUR\_CHAINSTACK\_ENDPOINT — your node HTTPS or WSS endpoint

* NETWORK\_ID — Optimism network ID:

  * Mainnet: `10`
  * Testnet: `420`

Example to run the deployment script:

<CodeGroup>
  ```shell Shell theme={"system"}
  brownie run deploy.py --network chainstack-testnet
  ```
</CodeGroup>

## Foundry

1. Install [Foundry](https://getfoundry.sh/).
2. Use `--rpc-url` to run the operation through your Chainstack node.

### Forge

Use `forge` to develop, test, and deploy your smart contracts.

To deploy a contract:

<CodeGroup>
  ```shell Shell theme={"system"}
  forge create CONTRACT_NAME --contracts CONTRACT_PATH --private-key YOUR_PRIVATE_KEY --rpc-url YOUR_CHAINSTACK_ENDPOINT
  ```
</CodeGroup>

where

* CONTRACT\_NAME — name of the contract in the Solidity source code
* CONTRACT\_PATH — path to your smart contract
* YOUR\_PRIVATE\_KEY — the private key to your funded account that you will use to deploy the contract
* YOUR\_CHAINSTACK\_ENDPOINT — your node HTTPS endpoint protected either with the key or password

### Cast

Use `cast` to interact with the network and the deployed contracts.

To get the latest block number:

<CodeGroup>
  ```bash Shell theme={"system"}
  cast block-number --rpc-url YOUR_CHAINSTACK_ENDPOINT
  ```
</CodeGroup>

where YOUR\_CHAINSTACK\_ENDPOINT is your node HTTPS endpoint protected either with the key or password

## GraphQL

You can use GraphQL on a dedicated node on the [paid plans](https://chainstack.com/pricing/).

### UI

You can query data using the graphical interface.

1. On Chainstack, navigate to your dedicated Ethereum node. See [node access details](/docs/manage-your-node#view-node-access-and-credentials).
2. Hover over **GraphQL IDE URL** and click **Open**.
3. In the graphical interface that opens, run a GraphQL query.

Example to get the latest block number:

<CodeGroup>
  ```graphql GraphQL theme={"system"}
  { block { number } }
  ```
</CodeGroup>

### Node.js

You can build a web app to query data using node.js and [axios](https://www.npmjs.com/package/axios):

<CodeGroup>
  ```javascript Javascript theme={"system"}
  const axios = require('axios');
  const main = async () => {
    try {
      const result = await axios.post(
        'YOUR_CHAINSTACK_ENDPOINT',
        {
          query: `
            { block { number } }
          `
        }
      );
      console.log(result.data);
    } catch(error) {
      console.error(error);
    }
  }
  main();
  ```
</CodeGroup>

where

* YOUR\_CHAINSTACK\_ENDPOINT — your node GraphQL endpoint protected either with the key or password. See [node access details](/docs/manage-your-node#view-node-access-and-credentials).
* `query` — your GraphQL query. In this case, to get the latest block number.