# Arbitrum

<figure><img src="https://3091755030-files.gitbook.io/~/files/v0/b/gitbook-x-prod.appspot.com/o/spaces%2FENUSv6WO6gDHge2JXsI2%2Fuploads%2FksvQ4yWKyXgk4tRMolLq%2FPrimary_horizontal_RGB.png?alt=media&#x26;token=5e9031c2-bb66-437d-993c-7e46bc7b012f" alt="Arbitrum Logo"><figcaption></figcaption></figure>

## Introduction

The [**Arbitrum network**](https://arbitrum.io/) is a Layer 2 scaling solution for Ethereum, designed to enhance the speed and cost-efficiency of transactions while maintaining the security and decentralization of the Ethereum blockchain. It achieves this by leveraging **Optimistic Rollups**, a technology that processes transactions off-chain and posts summarized data to Ethereum for verification.

#### Key Features of Arbitrum:

1. **Layer 2 Scaling**:
   * Arbitrum processes most transactions off-chain, reducing congestion and lowering fees compared to Ethereum's mainnet.
2. **Optimistic Rollups**:
   * This approach assumes transactions are valid ("optimistically") and only runs computation on-chain if there is a challenge, enhancing efficiency.
3. **Ethereum Compatibility**:
   * Fully compatible with Ethereum smart contracts, allowing developers to migrate existing dApps to Arbitrum with minimal changes.
4. **Low Fees**:
   * By processing transactions off-chain, Arbitrum significantly reduces gas fees for users.
5. **Fast Transactions**:
   * Transactions are processed more quickly than on the Ethereum mainnet, improving user experience.
6. **Secure by Ethereum**:
   * All data and transaction proofs are ultimately secured by Ethereum's robust consensus mechanism.
7. **Arbitrum One**:
   * The flagship rollup chain under the Arbitrum ecosystem, widely used for decentralized finance (DeFi) and NFT applications.
8. **Arbitrum Nova**:
   * A separate chain optimized for gaming and social applications with high transaction throughput needs.

Arbitrum is popular among developers and users seeking cost-effective, scalable solutions while leveraging Ethereum's decentralized and secure environment.

## How to Interact

1. Get your API Key from [Forbole's RPC](https://rpc.forbole.com/).

<figure><img src="https://3091755030-files.gitbook.io/~/files/v0/b/gitbook-x-prod.appspot.com/o/spaces%2FENUSv6WO6gDHge2JXsI2%2Fuploads%2FnruHAOu3SGjYS3dRQEww%2FScreenshot%202025-01-08%20at%202.46.26%E2%80%AFPM.png?alt=media&#x26;token=44be1250-1bb5-4b21-8fee-a003a682ddf1" alt="DevTools Endpoints"><figcaption></figcaption></figure>

1. Test the query as follow:

```bash
curl https://rpc-mainnet-arbitrum-fullnode.forbole.com \
  -X POST \
  -H "Content-Type: application/json" \
  -H "apikey: {apiKey}" \
  -d '{"jsonrpc":"2.0","id":1,"method":"eth_blockNumber"}'
```

**Response Example**

```json
{
    "jsonrpc": "2.0",
    "id": 1,
    "result": "0x10c288b1"
}
```