PasaTanda

PasaTanda digitizes the Latin American "Pasanaku, Tanda, Rosca", a collaborative savings model used by millions but plagued by operational chaos, manual payment risks, and inflation losses. Since many interactions in the region already happen on WhatsApp, we brought the solution directly to the chat. PasaTanda is a SocialFi platform that allows users to create savings circles managed by an AI Agent. Users interact via WhatsApp to organize rounds and verify payments. Unlike the traditional model where money sits idle, PasaTanda routes funds into Sui Network smart contracts, where they are deployed into DeFi protocols to generate yield, protecting users' savings from devaluation. We leverage Sui's zkLogin to provide a seamless Web3 onboarding experience—users login with their Google account, eliminating the need for seed phrases. PasaTanda transforms a manual, high-risk tradition into a secure, yield-bearing, and fully automated financial tool.

PasaTanda is built as a bridge between Web2 usability and Web3 power.

1. The AI Brain (Google Gemini): We use a Node.js backend connected to the WhatsApp Business API. The core intelligence is Google Gemini 1.5. We use Gemini Flash to interpret user intents via natural language (NLP) and Gemini Pro Vision to extract data from photos of fiat bank receipts (OCR), allowing us to verify off-chain payments instantly.

2. The Blockchain Layer (Sui Network): The financial logic lives entirely on Sui Move.

zkLogin: We implemented Sui’s zkLogin primitive. This allows users to own a non-custodial wallet derived from their Google credentials. No extensions or seed phrases are required.

Smart Contracts: Each savings circle is a shared Object in Move, managing rounds, participants, and fund distribution.

Sponsored Transactions: We utilize a Gas Station service to sponsor gas fees, ensuring users never need SUI tokens just to pay their savings quota.

DeFi Integration: The contracts are designed to interact with lending protocols on Sui, automatically supplying idle USDC to generate yield during the savings cycle.

We "hacked" the user experience by completely abstracting the blockchain: the user chats on WhatsApp, and our backend orchestrates the complex crypto transactions, signing them via zkLogin proofs in the background.