VETO

Inspiration

The Fatal Flaw of Modern Money: Finality without Consent. Modern financial systems have a structural tragedy: Banks are too slow to intervene, and Blockchains are too fast to reverse. Once a user clicks Send, the system assumes the decision was rational—even when it was the result of psychological manipulation. Authorized Push Payment (APP) fraud is now a multi-billion dollar crisis because scammers hack the human, not the code. We built VETO to introduce "Intelligent Friction," giving users a power they’ve never had: The power to stop a mistake after it happens.

What it does

VETO is a safety layer and "Circuit Breaker" for programmable finance. It breaks the urgency that scammers rely on by separating Authorization from Settlement:

• AI-Driven Risk Detection: Instead of just blacklisting addresses, VETO uses AI to detect "Scam Signatures" like the Penny Drop pattern, hyper-urgent behavior, and brand-new recipient addresses.
• The Smart Vault (Cooling-Off Period): When high risk is detected, funds are moved out of the user’s wallet into a Time-Locked Smart Vault. This keeps the funds secure without alerting the scammer.
• The Veto Power: During this safety window, the user has the absolute right to hit the Veto Button, instantly reversing the transaction and pulling their funds back from the vault.

How we built it

We built a production-grade full-stack prototype:

• Mobile Interface: Developed with React Native (Expo), focusing on "Calm Tech" UX to reduce user panic during high-stress moments.
• Web Dashboard: Built with Next.js 14 for transparent monitoring of the Smart Vault and transaction history.
• The Brain (AI Risk Engine): A Python/FastAPI backend using LangChain and Gemini. It provides real-time, explainable risk verdicts.
• The Muscle (Smart Contracts): Solidity contracts ensuring that "Code is Law," but "Code also allows for Correction."

Challenges we ran into

• Latency vs. Security: Running deep AI risk analysis in the milliseconds before a transaction broadcasts required heavy optimization of our FastAPI endpoints.
• On-Chain Logic: Simulating a "Probationary Transaction" without compromising the "instant" feel was a complex balance of state management between the frontend and the blockchain.
• Gas Efficiency: Routing funds through a middle-layer Vault increases gas, so we built efficient pre-transaction estimators to ensure users aren't blindsided by costs.

Accomplishments that we're proud of

• The "Undo" Moment: Successfully seeing a transaction reverse and tokens return to the wallet after a simulated scam.
• Explainable AI: Moving beyond "Black Box" models to an AI agent that can explain why it flagged a transaction (e.g., "Detected Penny Drop pattern").
• Holistic Protection: Creating a system that protects the most vulnerable users without stripping away their financial autonomy.

What we learned

We learned that Trust is the ultimate utility. While the industry focuses on "Trustless" systems, the average user needs a system they can trust to protect them. We also gained deep insights into how psychological triggers (Urgency/Fear) can be mapped into deterministic data patterns for AI detection.

What's next for VETO

• VETO SDK: Building an API so any wallet or dApp can integrate our "Undo Button" logic.
• Guardian Network: Introducing social recovery where a trusted guardian can help "Veto" high-value suspicious transactions.
• Cross-Chain Interoperability: Expanding the Smart Vault logic to ecosystems like Solana and NEAR.
• Institutional Partnerships: Collaborating with Neo-banks to bring this safety layer to traditional fiat transfers.

Built With

• ether.js
• expo.io
• fastapi
• gemini
• langchain
• nativewind
• next.js
• python
• react-native
• solidity