In this tutorial we will explain how to use Optimistic Ethereum layer 2 Mainnet and Testnet. We will review how to configure your MetaMask wallet. Then explain how to transfer funds using the Optimistic Ethereum Gateway. Finally we will list resources for additional information.
Optimism is a complex layer two scaling solution that is compatible with the Ethereum Virtual Machine. Optimism uses rollup technology to help scale the Ethereum blockchain. A rollup is a sidechain aggregation of transactions in a smart contract that will settle to the main chain at some future point. The goal of the platform is to speed up transactions and reduce gas costs on the Ethereum network.
Configure MetaMask for the Optimistic Ethereum Mainnet Network
First open MetaMask and select:
- Settings
- Network
- Then select Add Network
Copy and past the information below in a text editor. It will make it easier to put this information into MetaMask and will prevent the screen from closing on you.
Type the below information into MetaMask:
- Network Name: Optimistic Ethereum
- New RPC URL:
https://mainnet.optimism.io - Chain Id: 10
- Currency Symbol: ETH
- Block Explorer URL:
https://optimistic.etherscan.io
Finally, press the save button on MetaMask. Once you are done you should now see an Optimism banner and network badge on app.uniswap.org. To switch back to layer 1 click on the network badge and select switch to Ethereum. Visit the uniswap help documentation to perform these setup tasks automatically (link to auto setup).
Transfer Funds from Ethereum to Optimistic Ethereum on the Mainnet
If you want to transfer Ethereum to Optimism you can use the Optimistic Ethereum Gateway. This bridge is new and experimental (like all new technology) and you can read more about it here. You will need to connect your wallet and sign your transaction in order to make a deposit. Like other bridges in the ecosystem it takes approximately 10 minutes for funds to transfer.
Liquidity and trading using Uniswap on Optimism
To learn how to swap tokens and provide liquidity on Uniswap with low fees and fast confirmation use the appropriate links above. Once you try this service you will be amazed at how fast and cheap transactions are on Optimism. Great technology takes time to develop.
Optimistic Ethereum Kovan testnet
Optimistic Ethereum layer 2 is on the Kovan testnet. If you would like to deploy your smart contracts on the Optimistic Ethereum Kovan testnet configure MetaMask with the following information:
Copy and past the information below in a text editor. It will make it easier to put this information into MetaMask and will prevent the screen from closing on you.
Type the below information into MetaMask:
- Network Name: Optimistic Kovan
- New RPC URL:
https://kovan.optimism.io - Chain Id: 69
- Currency Symbol: ETH
- Block Explorer URL:
https://kovan-optimistic.etherscan.io - WebSocket Endpoint:
https://ws-kovan.optimism.io
Optimism Faucet
The Optimism node will charge you transaction fees that are equivalent to Mainnet fees. You can bypass gas fees locally by setting gasPrice: 0 to your transactions. If you want to deploy a contract to the testnet, you will need to use the ETH Gateway to deposit some test ETH into the layer 2 test environment. Read their documentation for more information.
Uniswap Kovan testnet
The Unipig exchange is the Uniswap exchange running on the Optimistic Ethereum Kovan testnet. It demonstrates the improvements that are possible with layer 2 solutions. To test Uniswap on the Optimistic Ethereum Kovan testnet visit Unipig exchange.
Additional information about Optimism
- Documentation – https://community.optimism.io/docs/
- Tutorial – https://optimism.io/demos
- Github – https://github.com/ethereum-optimism
- Discord Server – https://discord.com/invite/jrnFEvq
Resources
Blockchain Networks
Below is a list of EVM compatible Mainnet and Testnet blockchain networks. Each link contains network configuration, links to multiple faucets for test ETH and tokens, bridge details, and technical resources for each blockchain. Basically everything you need to test and deploy smart contracts or decentralized applications on each chain. For a list of popular Ethereum forums and chat applications click here.
 | Ethereum test network configuration and test ETH faucet information |
 | Optimistic Ethereum Mainnet and Testnet configuration, bridge details, etc. |
 | Polygon network Mainnet and Testnet configuration, faucets for test MATIC tokens, bridge details, etc. |
 | Binance Smart Chain Mainnet and Testnet configuration, faucets for test BNB tokens, bridge details, etc. |
 | Fanton networt Mainnet and Testnet configuration, faucets for test FTM tokens, bridge details, etc. |
 | Kucoin Chain Mainnet and Testnet configuration, faucets for test KCS tokens, bridge details, etc. |
Web3 Software Libraries
You can use the following libraries to interact with an EVM compatible blockchain.
- Python: Web3.py A Python library for interacting with Ethereum. Web3.py examples
- Js: web3.js Ethereum JavaScript API
- Java: web3j Web3 Java Ethereum Ðapp API
- PHP: web3.php A php interface for interacting with the Ethereum blockchain and ecosystem.
Nodes
Learn how to run a Geth node. Read getting started with Geth to run an Ethereum node.
Fix a transaction
How to fix a pending transaction stuck on Ethereum or EVM compatible chain
Next – Multiple ways to upgrade a Solidity smart contract
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