Subscriptions are a cash sink: you pay every month, nothing comes back.
Traditionally prepaying for subscriptions is inconvenient - merchants rarely offer it, and it locks you in.
Subscription tracker apps only monitor charges; they don’t reduce them.
Cancelling means chasing down each merchant individually.
Card overcharges or failed payments can disrupt services unexpectedly.
What it does
You prepay for your monthly subscriptions for a year, and Subsave puts that money into a DeFi yield vault.
The vault generates yield, effectively making subscriptions cheaper over time.
You get the flexibility of monthly cancelation, even while committing funds up front.
This means you spend less than a yearly subscription without being locked in.
All blockchain complexity is abstracted away - users just see a simple dashboard and lower costs.
How we built it
Frontend: Built with Expo + React Native Paper for a clean, mobile-first experience. The dashboard, vault detail, and notifications screens give users full visibility into balances and charges.
Authentication: Auth0 handles secure login and user identity management.
Database: MongoDB Atlas stores user profiles, subscription vaults, and payment history.
Blockchain under the hood: Subsave is designed to connect to DeFi vaults through Squads Grid SDK, which handles programmable accounts, spending caps, and automated payments.
Abstraction layer: All blockchain interactions are wrapped in simple service calls, so users only see their savings grow while the complexity stays hidden.
Challenges we ran into
Bridging TradFi and DeFi: Designing a system that feels like a regular finance app while actually running on blockchain rails was tricky. We had to abstract away the crypto concepts without losing their benefits.
Yield Simulation: In a hackathon setting, we simulated yield accrual to show savings over time, while keeping the path open for connecting to real protocols later.
Cancelation Flexibility: Giving users the ability to prepay yet still cancel monthly meant carefully modeling vault withdrawals and policy logic.
User Trust: Subscriptions touch sensitive financial data. Designing flows that feel transparent and secure was critical.
Accomplishments that we're proud of
Built a working mobile dashboard where users can add subscriptions, see balances, and track upcoming charges.
Designed a vault system that bridges prepaid funds with yield-generating accounts.
Created a flow where subscriptions are effectively cheaper without requiring merchants to change anything.
Made blockchain infrastructure invisible to the user, keeping the UX simple and approachable.
What we learned
Users don’t care about the rails, they care about cheaper subscriptions and flexibility. Abstracting away DeFi concepts is the key to mainstream adoption.
Even small amounts of yield can create meaningful savings when paired with recurring payments.
Designing around trust and transparency is as important as the financial mechanics. Clear dashboards and notifications matter.
Hackathon speed forces clarity, we had to focus on the core loop: deposit -> yield -> automatic payments -> cancel anytime.
What's next for Subsave
Real DeFi integration: Plug into actual yield-generating protocols and stablecoin vaults.
Full Grid SDK support: Automated spending limits, programmable vaults, and virtual accounts.
Group vaults: Let families, roommates, or teams pool money for shared subscriptions.
AI insights: Smart nudges that recommend when to cancel unused subscriptions or prepay for better savings.
Beyond subscriptions: Extend the model to utilities, insurance, and memberships - any recurring expense.
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