OP Mainnet (Optimism) is a Layer 2 scaling solution for Ethereum that leverages optimistic rollups to provide fast and low-cost transactions. As the foundation of the Optimism Superchain, OP Mainnet offers a secure and scalable environment for deploying Ethereum-based applications.

The OP Mainnet API facilitates interaction with the OP Mainnet network through a collection of JSON-RPC methods. Given its compatibility with the Ethereum ecosystem, developers familiar with Ethereum’s JSON-RPC APIs will find working with OP Mainnet both intuitive and straightforward.

Send Your First Request on Alchemy

Let’s use the viem package to create an OP Mainnet client connected to Alchemy and fetch the latest block number!

npm install --save viem

Create Client Connected to Alchemy

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import { createPublicClient, http } from "viem"; 
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import { optimism } from "viem/chains";
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const client = createPublicClient({
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  chain: optimism,
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  transport: http("https://opt-mainnet.g.alchemy.com/v2/YOUR_ALCHEMY_API_KEY"),
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});

Now that you’ve created a client connected to Alchemy, you can continue with some basics:

Get Latest Block Number

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const blockNumber = await client.getBlockNumber();
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console.log("Current block number:", blockNumber);

Get an Address Balance

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const balance = await client.getBalance({ address: "0xab5801a7d398351b8be11c439e05c5b3259aec9b" });
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console.log("Balance (ETH):", Number(balance) / 1e18);

Read Block Data

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const block = await client.getBlock({
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  blockNumber: blockNumber, // from previous example
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});
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console.log(block);

Fetch a Transaction by Hash

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const tx = await client.getTransaction({ hash: "0xYOUR_TX_HASH" });
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console.log(tx);

Fetch Transaction Receipt

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const receipt = await client.getTransactionReceipt({
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  hash: "0xYOUR_TX_HASH"
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});
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console.log(receipt);

OP Mainnet APIs

For the full list of OP Mainnet APIs, see the OP Mainnet API Endpoints.