Inspiration
We wanted to solve two common problems: people struggle to save money, and crypto investors lose funds during sudden market crashes. We thought – why not build something that handles both automatically?
What it does
Sage connects your bank account and crypto wallet. It: Rounds up your daily purchases (like coffee) and saves the spare change as crypto Watches the crypto market 24/7 If prices start crashing, it automatically moves your money from risky investments to a safe savings vault Shows everything on one simple dashboard with a "weather forecast" for the market
How we built it
Frontend: Next.js with Tailwind CSS for a clean, responsive UI Backend: Node.js + Express to handle logic and API calls Database: MongoDB Atlas to store user transactions and round-ups Blockchain: Solidity smart contracts deployed on Sepolia testnet Banking: Plaid API (sandbox mode) to simulate bank connections Wallet: MetaMask SDK for crypto wallet connection Market data: CoinGecko API to track ETH prices
Challenges we ran into
Making the bank API (Plaid) talk smoothly with the blockchain part Simulating market volatility in a realistic way for the demo Writing smart contracts that can be triggered automatically by the backend Keeping everything working within free tier limits Coordinating data between traditional banking and Web3
Accomplishments that we're proud of
Successfully connected traditional banking with DeFi in one app Built a working automated "sweep" function that moves funds between contracts Created a clean, intuitive dashboard that non-crypto users can understand Finished a functional MVP within hackathon time constraints Made complex blockchain interactions feel simple to the user
What we learned
How to integrate banking APIs with blockchain technology Writing and deploying smart contracts on testnets Building full-stack apps with Web3 components That automating finance can be both powerful and tricky How to scope a project to deliver a working demo in limited time
What's next for Sage: Smart DeFi Vault
Add real machine learning to predict market volatility instead of simple rules Support more cryptocurrencies and blockchains Let users set their own risk preferences (aggressive vs conservative) Add mobile apps (React Native) Integrate with real banks and real DeFi protocols (not just testnets) Add social features – compare savings goals with friends
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