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

# Arbitrum (ARB) Overview

Arbitrum (ARB) RPC

Use Uniblock's JSON-RPC endpoint to access Arbitrum (ARB) with low-latency routing and a single API surface across providers.

## What is Arbitrum?

Arbitrum is an EVM-compatible mainnet. Its ticker symbol is `ARB`.

## What is the Arbitrum (ARB) JSON-RPC API?

The JSON-RPC API is the standard interface for reading chain state, sending transactions, and interacting with smart contracts where supported.

## Making API requests

Send a POST request to `https://api.uniblock.dev/uni/v1/json-rpc?chainId=42161`. Include the JSON-RPC method and params in the request body.

## Supported networks

| Network          | Symbol | Type    | Chain ID |
| ---------------- | ------ | ------- | -------- |
| Arbitrum         | `ARB`  | Mainnet | `42161`  |
| Arbitrum Sepolia | `ARB`  | Testnet | `421614` |

## API reference

Browse the available method groups for this chain:

* [Arbtrace](/reference/jsonrpc-docs/42161/arbtrace/arbtrace-block)
* [Debug](/reference/jsonrpc-docs/42161/debug/debug-account-range)
* [EVM](/reference/jsonrpc-docs/42161/evm/eth-accounts)