No real funds are needed at any point — everything below runs on testnets.
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
curlavailable.
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 Expected result:
https://sepolia.optimism.io and its chain ID is 11155420.
Verify you can reach it:{"jsonrpc":"2.0","id":1,"result":"0xaa37dc"} (0xaa37dc = 11155420).
For other networks and production-grade endpoints, see Networks 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.
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).
Need help?
- Ask a question or report documentation issues on the Optimism monorepo issue tracker.