Murat Tekin, 16.04.2022 Web3 and Flutter Building a Twitter Feed with Solidity and Flutter Smart Contract Flutter App Web3 Smart Contract Flutter App Web3 Flutter App Smart Contract Web3 At its core, Web3 uses blockchains, cryptocurrencies , and NFTs to give power back to the users in the form of ownership Ethereum Foundation “ Web3 Core ideas of Web3 • No centralised entities • Distributed amongst its builders and users Decentralised • Equal access to everyone • No one gets excluded Permissionless • Cryptocurrencies • No banks nor payment processors infrastructure used Native payments • Uses incentives and Economic mechanisms to operate Trustless # Web3 Computer programs stored on the blockchain Smart Contract What is a smart contract ? ++ very logical ++ digitised agreements with visible terms ++ trust-less and automatic execution ++ predictable outcomes ++ public records ++ privacy protection # Smart Contract Writing a Tweet A record of all Tweets Emit event when there is a new Tweet Twitter Feed # Smart Contract Record of Tweets # Smart Contract Tweet # Smart Contract Tweet Event # Smart Contract ABI # Smart Contract # JSON file describing the deployed contract and its functions # to understand the contract and call contract’s functions # think of GraphQL schemas or OpenAPI .yaml files Application binary interface Flutter Demo # Flutter Dependencies # Flutter Initialise Web3 Client # Flutter Generate Contract # Flutter # Save your ABI into a file, suffixing it with .abi.json # The build runner will detect the file type and auto-generate your contract Initialise Contract # Flutter Get All Tweets # Flutter