There are two networks on Arbitrum: Mainnet and Rinkeby Testnet. The endpoints are as follows: Mainnet: https://arb-mainnet.g.alchemy.com/v2/your-api-key Rinkeby: https://arb-rinkeby.g.alchemy.com/v2/your-api-key
After clicking Save, you will be directly switched to Arbitrum’s Network within the dropdown list.
That's it! You've now added the Arbitrum network with Alchemy connected.
Update Arbitrum Testnet (Rinkeby)
Arbitrum currently has one testnet connected to Ethereum's Rinkeby testnet. This operates exactly the same as Arbitrum mainnet but is built as a smart contract on Rinkeby instead of on Ethereum mainnet.
Adding the testnet is the same process as adding the mainnet shown above, but with a different RPC endpoint.
1. First, make sure you’ve enabled the Show test networks toggle.
This will list all the default test networks within your network list. You can find this in Settings>Advanced>Show test Networks
2. Enter the following network details and click Save
Network Name: Arbitrum Testnet
New RPC URL: https://arb-rinkeby.g.alchemy.com/v2/your-api-key