ZkMicroPay

Inspiration The world runs on micro-interactions — likes, streams, data calls, and in-game actions — yet current payment systems can’t handle them efficiently. High fees and slow settlement make true microtransactions impossible. Inspired by Starknet’s zero-knowledge scalability and Ethereum-grade security, we built ZkMicroPay to make instant, sub-cent payments a reality for everyone, from gamers to developers to creators. What it does ZkMicroPay is a decentralized micropayment protocol on Starknet that enables instant, ultra-low-fee transactions with built-in privacy and cross-chain support. Users can send or stream payments as small as a fraction of a cent — instantly, securely, and privately — with full transparency on-chain. Developers can embed ZkMicroPay into games, DeFi apps, or content platforms using a simple API and SDK. How we built it We built the MVP using: Starknet + Cairo for zero-knowledge smart contracts. Solidity for Ethereum interoperability modules. Starknet.js + React for the frontend wallet and dashboard. Atomiq bridge for BTC ↔ STRK liquidity. OpenZeppelin contracts for escrow and verification logic. Chipipay SDK for real-world off-chain conversions. Everything was deployed to the Starknet testnet, using zk batching contracts to process payments and proofs efficiently. Challenges we ran into Integrating Cairo-based ZK logic with existing Solidity frameworks required custom adapters. Cross-chain swaps through Atomiq needed gas abstraction and message signing synchronization. Balancing privacy and verification transparency was also a challenge — ensuring payments were hidden but still auditable. Accomplishments that we're proud of We achieved live sBTC and STRK micropayments with ZK-batched verification, all in under 2 seconds per transaction. The app supports embedded wallets, enabling one-click onboarding without extensions. Our design shows how ZK payments can scale to millions while keeping fees sub-cent and privacy intact. What we learned We learned how Starknet’s proof system can handle massive transaction throughput, and how ZK batching dramatically reduces cost without compromising trust. We also gained insights into cross-chain liquidity design, wallet UX, and how privacy-first infrastructure can be user-friendly and scalable at the same time. What's next for ZkMicroPay We plan to evolve ZkMicroPay into a universal microtransaction protocol supporting AI agent payments, IoT streaming, and creator monetization tools. Our next steps include: Full SDK release for developers. Launching a mobile wallet app integrated with Xverse. Deploying a mainnet version on Starknet. Partnering with game studios and content platforms for pilot integrations. ZkMicroPay’s goal is to become the backbone of the microtransaction economy — powering instant, global, private payments for the next wave of Web3 apps.

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