0xPay SDK

Problem Statement

The Problem Being Solved Traditional API billing systems require extensive infrastructure investment, complex integration processes, and often lack transparency in usage verification. API providers must build and maintain payment processing systems, handle disputes, and manage complex billing cycles, while users face trust issues regarding accurate usage reporting. Our Solution Framework Our platform transforms API monetization into a trustless, automated system where:API providers can monetize their services instantly without billing infrastructure Users maintain complete privacy over their API usage patterns Payments are automatically released based on cryptographically verified usage Real-time analytics provide comprehensive insights without compromising privacyTechnical Components Deep DiveSmart Contract Escrow System (PYUSD) Architecture: Our escrow system operates on a blockchain network supporting PYUSD (PayPal USD stablecoin), providing stability and regulatory compliance. Key Features:Deposit Management: Users deposit PYUSD into smart contract escrows tied to specific API services Automatic Release Mechanism: Payments are released automatically upon successful zero-knowledge proof verification (we use batching for speed) Multi-tier Pricing: Supports complex pricing models including rate limiting, usage tiers, and bulk discountsSmart Contract Logic: Escrow Creation → Usage Verification → ZK Proof Validation → Automatic Payment Release 2. Zero-Knowledge Proof System for Usage Verification Privacy-First Design: Our ZK implementation ensures that sensitive API usage data never leaves the provider's infrastructure while still enabling trustless verification. Technical Implementation:Proof Generation: API servers generate ZK proofs for usage metrics (request counts, data volume, compute time) without revealing actual request content or patterns Verification Layer: On-chain verifiers validate proofs without accessing underlying usage data Cryptographic Guarantees: Ensures computational integrity while maintaining complete privacy of API interactionsBenefits:API providers retain full control over their logs and response data Users' usage patterns remain private from both the platform and other users Eliminates trust requirements between parties while ensuring accurate billingThe Graph Substreams Integration Real-time Data Pipeline: Our system utilizes The Graph's Substreams service for high-performance, real-time indexing of blockchain events related to the platform. Indexing Capabilities:Transaction Monitoring: Tracks all escrow deposits, withdrawals, and payment releases Usage Analytics: Indexes verified usage proofs for dashboard analytics Performance Metrics: Monitors API response times, success rates, and service availability User Behavior Patterns: Aggregated (privacy-preserving) insights into platform usage trendsDashboard Features:Real-time usage monitoring for both providers and consumers Historical analytics with customizable time ranges Predictive analytics for usage forecasting and capacity planning Automated alerting for unusual patterns or system issuesWorkflow Architecture For API ProvidersOnboarding: Register API endpoints and define pricing models Integration: Implement our lightweight SDK for ZK proof generation Monetization: Automatic revenue collection without payment processing overhead Analytics: Access comprehensive usage and revenue analyticsAutomated Payment FlowUser makes API request API server processes request and generates usage proof (we use batching for efficiency) ZK proof is submitted to blockchain for verification Upon verification, corresponding payment is released from escrow Transaction is indexed by Substreams for real-time dashboard updatesKey Advantages For API ProvidersZero Infrastructure Overhead: No need to build billing, payment processing, or user management systems Instant Monetization: Start charging for APIs immediately without complex integrations Reduced Risk: Guaranteed payments through our escrow system eliminates payment defaults Privacy Control: Maintain complete control over API data and logs Transparent Analytics: Clear visibility into usage patterns and revenue streamsFor API UsersUsage-Based Pricing: Pay only for what they actually use Transparency: Cryptographic proof of accurate billing Privacy Protection: Usage patterns remain completely private Flexible Budgeting: Deposit and spend according to actual needs Real-time Monitoring: Track usage and costs in real-timeFor the EcosystemTrustless Operations: Eliminates need for trust between parties Regulatory Compliance: PYUSD provides regulatory clarity for financial operations Scalable Architecture: Supports massive scale through efficient ZK proofs and blockchain infrastructure Developer-Friendly: Simple integration with existing API infrastructureInnovation Differentiators Privacy-Preserving Monetization: Our combination of ZK proofs with blockchain escrows creates the first truly private API billing solution. Infrastructure Minimalism: API providers need minimal changes to existing systems while gaining sophisticated billing capabilities. Real-time Transparency: Our Substreams integration provides unprecedented real-time visibility into API ecosystem health and usage patterns. Financial Innovation: Leveraging PYUSD creates a bridge between traditional financial systems and decentralized API economies.

Solution

How It’s Made:0xPay-SDK is designed to effortlessly turn any API into a paid service by integrating crypto payments, PayPal USD (PYUSD), and leveraging zk-SNARKs for security and privacy. Here’s a breakdown of how we built it:Key Technologies Used:Smart Contracts (Solidity):Solidity smart contracts handle the Escrow management, payment processing, and settlement of PYUSD between users and providers.The contracts ensure that funds are securely held in escrow until API usage is validated, then released to the provider.zk-SNARKs (Noir Proofs):zk-SNARKs (Zero-Knowledge Succinct Non-Interactive Arguments of Knowledge) are used to generate privacy-preserving proofs of API usage. The Noir language is used to create cryptographic proofs that validate API consumption without revealing sensitive data, ensuring privacy and security.Crypto Payments (PayPal USD - PYUSD):PYUSD (PayPal USD) is a stablecoin tied to the US dollar, making it a reliable and stable choice for transactions.Using PayPal USD ensures that users and API providers can transact in a stable currency, avoiding the price volatility typically seen with other cryptocurrencies. This makes PYUSD a perfect fit for handling real-time payments securely.SDK Integration (JavaScript/TypeScript):The 0xPay-SDK is written in JavaScript/TypeScript, allowing for easy integration into any API. Developers can simply add the SDK to their backend, and it automatically handles payments, proof generation, and settlements—all without needing blockchain expertise.Substreams for Event Tracking:Substreams emit on-chain events for key actions like deposits, payments, and withdrawals. These events provide real-time tracking of transactions and are essential for providing transparency and analytics.Immutable Storage (Akave Cloud):All transaction records, including payment receipts and usage logs, are archived in Akave Cloud. This ensures that all data is stored immutably, providing a tamper-proof and transparent record of every transaction.How Technologies Fit Together:User Deposit (Escrow):Users deposit PYUSD into an Escrow account through the SDK, ensuring that the payment is securely held until API usage is validated.API Usage and Proof Generation:The SDK tracks API usage and generates a zk-SNARK proof, verifying the usage without exposing any sensitive data about the specific API requests.Batch Payment Submission:The SDK submits a processBatchPayment request to the smart contract, moving the appropriate amount of PYUSD from the user’s Escrow account to the API provider’s account.Provider Withdrawal:Once the payment is processed, the API provider can withdraw the PYUSD from the Escrow account.Real-Time Analytics:Substreams emits on-chain events, allowing both users and providers to track real-time analytics for API usage and payments.Immutable Record Keeping (Akave Cloud):All transaction data, including receipts and logs, is archived in Akave Cloud, ensuring that the data is immutable and available for audit and monitoring.Notable Details:Smart Contract Optimization: We optimized gas usage by using batch payments, processing multiple transactions in one go to minimize costs and improve efficiency.Privacy via zk-SNARKs: The zk-SNARKs proof system guarantees that sensitive data is private while still allowing for accurate verification of API usage.Stable Payments with PYUSD: The use of PayPal USD (PYUSD) ensures that all transactions are stable and secure, making it easy for users and providers to transact without worrying about crypto volatility.Partner Technologies and Their Benefits:PayPal USD (PYUSD): PYUSD, as a PayPal-backed stablecoin, provides a reliable, stable payment method for API transactions. With PayPal's reputation and security backing it, users and providers can trust the reliability and stability of the currency.Akave Cloud: Akave Cloud offers immutable and tamper-proof storage for all transaction records, providing long-term data integrity and auditability for all payments and API usage.Substreams: Substreams enables real-time event tracking for blockchain interactions, giving users and providers visibility into transaction statuses, usage patterns, and payment history.Conclusion:0xPay-SDK offers a simple, secure way to monetize APIs using crypto payments with PayPal USD (PYUSD), zk-SNARKs for privacy, and immutable storage via Akave Cloud. Developers can easily integrate the SDK into their APIs, while the SDK automatically handles payments, settlements, and transparent record-keeping. With PayPal USD, users and providers benefit from a stable and trusted payment method, offering a reliable foundation for API monetization without the volatility of traditional cryptocurrencies.