# Rainbow App > Intended for developer information The web3 app uses [RainbowKit](https://www.rainbowkit.com/) to authenticate Ethereum users. When deploying, the app requires either a `ALCHEMY_API_KEY` or `INFURA_API_KEY` (or both) which can be obtained by creating an Alchemy or Infura project respectively. Find your Alchemy API key Find your Infura API key Available blockchains are Ethereum mainnet, Arbitrum, Optimism, and Polygon mainnet.