Tap Yield

Inspiration

Millions of families around the world depend on remittances from relatives working abroad. But when that money arrives, it usually sits in a single account and slowly gets spent on everyday expenses. Funds meant for important goals, like school fees, rent, or medical bills, often disappear before the deadline arrives.

Development economists call this the “mental accounting gap.” People know what they want to save for, but they lack tools that help enforce those commitments.

Traditional banks sometimes offer locked savings accounts, but they’re often inaccessible, inflexible, or unavailable to underbanked populations. At the same time, modern fintech apps in wealthier countries offer goal-based savings, but those systems rely on centralized institutions to enforce the rules.

We wanted to explore whether blockchain could enable self-enforced commitment savings that don’t rely on banks or intermediaries.

That idea became TapYield.

What it does

TapYield is a commitment savings wallet built on the XRP Ledger that helps users protect money for important goals while still enabling everyday spending.

Users can divide their funds into three buckets:

Locked savings goals (e.g., school fees, medical bills)

Available spending balance

Yield earnings

Savings goals are enforced using XRPL’s native escrow feature, which locks funds until a chosen release date. Because this rule is enforced by the protocol itself, the funds cannot be spent early.

At the same time, the user’s spending balance can be deposited into XRPL’s automated market maker (AMM) pools to earn yield.

When the user wants to make a purchase, they simply tap an NFC card at a merchant’s phone, triggering an on-chain withdrawal from the yield pool and an instant payment.

The result is a wallet that lets users save with commitment, earn yield, and pay instantly, without relying on traditional banks.

How we built it

TapYield is built as a mobile-first web application with three layers:

Frontend

Mobile web wallet for users to view balances, savings goals, and transactions
Merchant terminal interface for entering payment amounts and accepting NFC taps
Built with React and designed with a simple fintech-style UI

Backend

Node.js + Express API server
Handles wallet creation, savings goal creation, pool deposits, and payment triggers
Uses WebSockets to update both phones in real time during transactions

Blockchain layer

Built with xrpl.js on the XRPL Testnet
Uses several XRPL-native features (Escrow, AMM Yield Pool, Payment)

For the tap-to-pay experience, we used NFC cards that contain a URL with the customer’s wallet address. When the merchant taps the card with an Android phone, the app reads the URL and triggers the payment flow.

Challenges we ran into

One of the biggest challenges was coordinating multiple blockchain transactions within a smooth user experience. The tap-to-pay flow requires withdrawing funds from the AMM pool and then executing a payment transaction, all while keeping the interface responsive.

Another challenge was simplifying complex blockchain mechanics into something users can intuitively understand. Concepts like escrow locks and liquidity pools needed to be translated into simple UI elements like goal cards, countdown timers, and spending balances.

We also had to carefully structure the architecture so the frontend, API server, and blockchain layer could be developed in parallel during a tight hackathon timeframe.

Accomplishments that we're proud of

We’re proud that TapYield successfully combines three XRPL-native features (escrow, AMMs, and payments) into a single user experience. Many blockchain projects demonstrate individual features, but our goal was to build a coherent product that feels useful and intuitive.

We’re also proud of the tap-to-pay demo experience, which allows a real-time payment to occur on the XRPL testnet after tapping an NFC card.

Most importantly, we created a prototype that shows how blockchain infrastructure can support commitment savings for underbanked communities, a concept that has been widely studied in development economics but rarely implemented with decentralized tools.

What we learned

Building TapYield taught us how powerful XRPL’s protocol-native features can be when combined thoughtfully.

Instead of writing complex smart contracts, we were able to rely on built-in primitives like escrow and AMMs. This reduces system complexity and improves reliability.

We also learned the importance of designing blockchain products from the user’s perspective. Users shouldn’t need to understand liquidity pools or escrow transactions—they just need to know that their money is protected, growing, and easy to use.

Finally, we learned how to coordinate rapid development across multiple layers—frontend, backend, and blockchain, under tight time constraints.

What's next for Tap Yield

TapYield is currently a hackathon prototype, but we see several exciting directions for future development.

First, we want to integrate real stablecoins such as RLUSD so users can hold and transact with stable-value assets instead of test tokens.

Second, we want to expand the savings system to support yield-generating locked funds, allowing escrowed savings to continue earning yield while locked.

Third, we would explore stronger NFC security mechanisms, such as cryptographic authentication between cards and merchant devices.

Ultimately, our vision is to build TapYield into commitment savings infrastructure for the global remittance economy, helping families protect the money they rely on for education, healthcare, and long-term financial stability.