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OP Stack chains are EVM equivalent: everything you know from Ethereum works here, and everything you build here works across the OP Stack ecosystem. This quickstart takes you from zero to a deployed contract on the OP Sepolia testnet, using only free testnet funds.
No real funds are needed at any point — everything below runs on testnets.

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Before you start

You’ll need:
  • A wallet you control (any EVM wallet works; you’ll export or generate a private key for testnet use only).
  • A terminal with curl available.
Use a fresh, testnet-only private key for tutorials. Never paste a key that holds real funds into a terminal.
1

Get testnet ETH

Grab free OP Sepolia ETH from the Superchain Faucet. Other options are listed on the testnet faucets page.
2

Connect to OP Sepolia

OP Sepolia’s public RPC endpoint is https://sepolia.optimism.io and its chain ID is 11155420. Verify you can reach it:
Expected result: {"jsonrpc":"2.0","id":1,"result":"0xaa37dc"} (0xaa37dc = 11155420). For other networks and production-grade endpoints, see network information and RPC providers.
3

Deploy your first contract

Follow the Deploy a contract to OP Sepolia tutorial. It walks you through installing Foundry, deploying a small Greeter contract, and reading and writing to it from the command line — the same workflow you’d use on Ethereum.
4

Bridge ETH between L1 and L2 (optional)

Apps often need to move assets between Ethereum and an OP Stack chain. Start with Bridging basics to understand the model, then follow the Bridging ETH with Viem tutorial to do a Sepolia → OP Sepolia deposit programmatically.

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Where to go next

Build apps on OP Stack chains

Development workflow, tooling, and what (little) is different from Ethereum.

Test your apps

Test against OP Stack chains locally and in CI.

Go cross-chain with interop

Build apps that span multiple Superchain chains.

Integrate DeFi with the Actions SDK

Lend, borrow, and swap with lightweight, type-safe modules (early preview — not production-ready).
Running your app in productionA production application depends on infrastructure your team does not run: RPC endpoints that hold up under real traffic (the public endpoints are rate-limited and not built for production), bridges your users rely on, and a chain whose operator keeps sequencing, upgrades, and incident response going around the clock. These docs cover building and testing. If your application is growing toward dedicated blockspace of its own, OP Enterprise offers managed and supported paths to running a chain. These docs stay the reference for what you build either way. OP Enterprise is Optimism’s managed offering.

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