Learn English, earn tokens, and mint soulbound NFT certificates — all on-chain.
LinguaChain is a Web3-powered language learning platform where users complete gamified lessons across CEFR levels (A1 to C2), earn badges, and mint verifiable certificates as soulbound NFTs.
Users start by connecting their wallet and taking a placement test. Each level contains a structured lesson path inspired by Duolingo. Completing lessons earns in-game tokens.
At the end of each level, users can take a time-limited, multiple-choice exam. Passing the exam mints a soulbound NFT certificate to their wallet. We use Self for privacy-preserving identity proofs during certificate minting.
Users can also buy avatars (NFTs) with USDC to increase their daily lesson limit, creating a dynamic educational game economy.
The frontend is built in Next.js 15 using shadcn/ui, TailwindCSS, TypeScript, and Wagmi + Viem for Ethereum wallet interactions and transactions.
Lesson paths, exams, and progress tracking use a combination of React state + local indexer and write-to-chain for certificates and rewards.
Soulbound certificate NFTs are minted with an ERC-721 + non-transferable modifier, and we used Self ID to verify wallet ownership before allowing certificate minting.
Lesson history and progress are uploaded using Walrus for decentralized and censorship-resistant storage.
The lesson flow uses custom logic and styling to mimic Duolingo UX while abstracting Web3 complexity behind simple actions (e.g., click = sign).