VETO

"The first 'Undo Button' for digital payments. VETO uses AI to stop Authorized Push Payment (APP) fraud in real-time, giving users the power to reverse a mistake after they click send."

Comment

Inspiration

Track: Best Programmable Finance & Automation

It’s not just about crypto. It’s about the finality of modern money. Modern money has a fatal flaw: finality without consent.

Across the world, people are losing money not because systems are hacked — but because people are manipulated. From WhatsApp lottery scams to fake college portals and urgent “account freeze” calls, Authorized Push Payment (APP) fraud has become one of the fastest-growing financial crimes.

The tragedy is structural:

  • Banks are too slow to intervene.
  • Blockchains are too fast to reverse.
  • Once a user clicks Send, the system assumes the decision was rational — even when it wasn’t.

We realized something important:

Programmable money doesn’t have to be instant — it can be intelligent.

MNEE gave us a unique opportunity to rethink payments at the infrastructure level. Instead of treating every transaction as final, we introduced the idea of a “probationary transaction” — where money can move conditionally, with safety built into the settlement itself.

VETO was built to protect people, not just wallets. It introduces intelligent friction into high-risk moments, giving users something they’ve never had before in digital payments: the power to stop a mistake after it happens.

What it does

VETO is a safety layer for programmable money. It acts as a circuit breaker for any transaction where the user might be under psychological pressure (Urgency, Fear, Greed).

Detects psychological manipulation (not just bad actors)

Instead of guessing intent, VETO looks for proven scam signatures, such as:

  • A “Penny Drop” pattern (small incoming → large outgoing)
  • Payments to brand-new or first-time addresses
  • Hyper-urgent behavior (copy-paste + send in seconds)
  • Duplicate payments triggered by “failed transaction” pressure

These patterns are explainable, deterministic, and grounded in real scam behavior.

Buys time — the universal antidote to scams

Scams rely on urgency. VETO breaks that pressure by separating authorization from settlement.

When risk is detected:

  • Funds leave the user’s wallet (to avoid tipping off scammers)
  • But are held in a smart-contract Vault
  • Settlement is delayed for a configurable safety window

This creates a cool-off period — time to think, verify, or ask for help.

Restores user control

If the user realizes something is wrong, they can:

  • Press VETO
  • Instantly cancel the transaction
  • Receive their funds back from the Vault

This isn’t just a feature — it’s a consumer right enforced by code.

How we built it

VETO is a full-stack, production-grade prototype designed for real-world use.

Mobile App (Primary Interface)

  • React Native (Expo)
  • Biometric confirmation and calm, high-contrast alerts
  • Designed for high-stress, real-world payment moments

Web App

  • Next.js 14
  • Wallet dashboard and Vault monitoring
  • Desktop access for transparency and review

AI Automated Risk Engine

  • Python + FastAPI
  • LangChain ReAct AI Agent for transaction risk reasoning
  • Powered by Gemini 2.5 Flash (with Groq/Mixtral fallback)
  • Uses custom tools to detect scam patterns and urgency behavior
  • Produces explainable, real-time risk verdicts (no traditional ML models)

Smart Contracts

  • Solidity on Ethereum (MNEE stablecoin)

  • Vault wrapper contract that:

    • Holds MNEE conditionally
    • Enforces time-locks
    • Enables user-initiated cancellation

  • Built directly around MNEE’s stable value to ensure trust during delayed settlement

Design Philosophy

  • “Calm Tech” UX
  • Green = safe, amber = caution, red = intervention
  • Designed to reduce panic, not increase it

Challenges we ran into

Real-time decision latency

Running AI risk checks between the mobile app and backend had to feel instant. We optimized our FastAPI endpoints to ensure decisions were returned in milliseconds.

Time-lock testing on-chain

Simulating delayed settlement required careful testing. We built custom scripts to validate:

  • Lock expiration
  • Early cancellation
  • Safe release after the delay

Gas & UX tradeoffs

Routing funds through a Vault costs more gas than a direct transfer. We added pre-transaction gas estimation to ensure users never hit an error during a critical safety moment.

Accomplishments we’re proud of

  • A real, working “Undo a Scam” flow Seeing MNEE tokens return from the Vault after pressing VETO validated the entire concept.

  • Security without fear-driven UX The intervention experience is clear and calming — not alarming or confusing.

  • End-to-end programmable finance From AI risk detection → smart-contract enforcement → user-controlled settlement.

This is not a mockup. It’s a functioning financial primitive.

What’s next for VETO

  • VETO SDK & API Allowing other wallets and apps to integrate our risk engine and Vault logic.

  • Guardian-based approvals Multi-party confirmation for high-value or elder-protection use cases.

  • Fiat & on-ramp protection Applying the same programmable delay logic to bank and on-ramp transfers.

  • Community risk intelligence Privacy-preserving sharing of known scam patterns across wallets.

Built With

Share this project:

Updates