Web3.js 4.x has been released. Checkout 4.x API documentation and migration guide for testing, early feedback and contributions. This is the Ethereum JavaScript API which connects to the Generic JSON-RPC spec. You need to run a local or remote Ethereum node to use this library. Additionally you can set a provider using web3.setProvider() (e.g. WebsocketProvider). We support types within the repo itself. Please open an issue here if you find any wrong types. If you are using create-react-app...