Ethernaut
Hack Solidity smart contracts on a test network
Ethernaut is a wargame where each level is a smart contract you must hack. You read the Solidity code, create your own instance of the level, and then send transactions to break it, for example by taking ownership or draining its funds. When you are done, you submit the instance to check your work.
Free · No login · Browser · Intermediate
About Ethernaut
It trains smart contract security and the common bugs in Solidity code. It suits developers who know some Ethereum basics. Many players work in the browser console with web3 helpers, and some use tools like Remix.
The game runs in the browser with a wallet such as MetaMask on the Sepolia test network. You need test ETH from a faucet to pay gas. It is open source under AGPL-3.0.
On Breakpoint since 23 Oct 2026.