SatsPay

SatsPay is a Bitcoin-powered Buy Now, Pay Later platform that lets users unlock the spending power of their sBTC without selling it by borrowing USD against locked sBTC.

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Inspiration

We were inspired by the financial principle of not selling appreciating assets to cover short-term needs. In the fiat world, people borrow against real estate or stocks — so why shouldn’t Bitcoiners be able to do the same? We realized there’s a huge gap in the current Web3 ecosystem: no truly intuitive BNPL platform built around non-custodial Bitcoin-backed lending. SatsPay bridges that gap.

What it does

SatsPay is a modern Buy Now, Pay Later platform powered by Bitcoin. Users can shop online and use their sBTC as collateral to make purchases — without selling it. The platform approves purchases instantly, locks the necessary collateral, and sets a flexible repayment schedule. Merchants get paid upfront, users keep their BTC exposure, and repayments are handled seamlessly through smart contracts.

How we built it

  • Frontend: Built with Next.js and Tailwind CSS for a clean, responsive UI across web and mobile.
  • Smart Contracts: Developed using Clarity, deployed on Stacks testnet.
  • BTC Collateral: Leveraged sBTC as the core mechanism to lock Bitcoin as collateral while enabling seamless contract interactions.
  • Wallet Integration: Integrated with Stacks Connect (Testnet).
  • BNPL Logic: Implemented time-based repayment tracking, liquidation logic for overdue loans, and interest-rate calculation using oracles.

Challenges we ran into

  • Smart contracts on Bitcoin: Building on Bitcoin with smart contract capabilities was new territory. Tools like Hiro documentation and LearnWeb3 helped.
  • sBTC Collateralization: Designing a trustless and transparent collateralization model was non-trivial, especially to prevent under-collateralization.
  • UX complexity: Balancing technical complexity with a user-friendly design — especially on mobile — was a constant challenge.

Accomplishments that we're proud of

  • Built a prototype of a Bitcoin-native BNPL app. -Designed a slick, intuitive interface users loved testing.
  • Integrated non-custodial wallet flows with real-time sBTC lockups and repayment logic.
  • Bridged the user experience gap between DeFi and real-world shopping.

What we learned

  • Bitcoin L2s are the future.
  • Designing for real-world use cases forces better architecture and UX decisions.
  • Non-custodial financial products can be just as seamless as traditional fintech — with the right abstraction layers.
  • Building in Web3 is 20% coding, 80% debugging weird behavior in wallets, SDKs, and node interactions.

What's next for SatsPay

  • Launch a closed beta with curated merchants to test out real-world usage.
  • Integrate dynamic credit scoring based on wallet history and reputation.
  • Add support for other Bitcoin L2s and more collateral types.
  • Explore partnerships with on-chain retail aggregators and NFT marketplaces.
  • Secure audit and pursue regulatory compliance for broader adoption.

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