> For the complete documentation index, see [llms.txt](https://hub.bsvblockchain.org/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://hub.bsvblockchain.org/demos-and-onboardings/demo-solutions/demos/digital-reciept/technical-digital-reciept.md). # Technical Documentation **Demo ID**: `demo-2025-004` **Version**: `[1.0.0]` **Last Updated**: `2025-09-05` ## Architecture Overview ### System Architecture The platform integrates retailer POS systems and a consumer mobile app via the BSV blockchain. * POS system generates receipt, encodes data into a blockchain transaction, produces a QR code for consumer verification. * Mobile app scans QR receipt, verifies authenticity against BSV blockchain, stores locally. ### Technology Stack * **Frontend**: Next.js 15, React 19, Tailwind CSS v4 (POS); React Native with Expo (mobile app) * **Backend**: Node.js Express server (POS QR generation and blockchain interaction) * **Database**: Local storage via AsyncStorage (mobile), NoSQL cache (POS server) * **Infrastructure**: Cloud-hosted demo environment with BSV node access ### Key Components 1. **QR Receipt Generator (POS)**: Encodes purchase data and transaction hash 2. **Mobile QR Receipt Scanner**: Decodes, verifies, and caches receipt locally 3. **Blockchain Integration Service**: Manages receipt minting, stores immutable record ## Integration & APIs ### External Dependencies | Service | Purpose | Version | Documentation | | -------------------- | ----------------------- | ------- | ----------------------------------------------------------------------------------- | | @bsv/sdk | BSV blockchain handling | Latest | [@bsv/sdk](https://github.com/bsv-blockchain/bsv-sdk) | | expo-barcode-scanner | QR code scanning | Latest | [Expo Barcode Scanner](https://docs.expo.dev/versions/latest/sdk/camera/#component) | | AsyncStorage | Local storage | Latest | [AsyncStorage Docs](https://react-native-async-storage.github.io/async-storage/) | ### API Endpoints ```bash GET /api/v1/receipts/:id POST /api/v1/receipts ``` ## Implementation Guide ### Prerequisites * Node.js (v18 or later), npm/yarn, Expo CLI (mobile) * POS server: Express/Node.js setup * BSV node RPC access or hosted crypto service ### Setup Instructions Clone repository (POS) ```bash git clone https://github.com/bsv-blockchain-demos/digital-receipts-pos cd digital-receipts-pos npm install
cd server node server.js npm run dev ``` Clone repository (Mobile) ```bash git clone https://github.com/bsv-blockchain-demos/digital-receipts-mobile cd digital-receipts-mobile npm install npx expo start ``` ### Configuration Key configuration parameters: * bsv\_node\_url: `[BSV RPC endpoint]` * local\_storage\_path: `[App config]` ## Testing & Validation ### Test Coverage * **Unit Tests**: 80% coverage POS, 85% coverage mobile * **Integration Tests**: Passed for receipt creation, scanning, and verification * **Performance Tests**: QR scan time < 2 sec; blockchain verification < 1 sec ### Validation Criteria * [ ] Receipt generates valid QR code * [ ] Receipt is immutable on blockchain * [ ] App caches and displays receipt ## Performance & Scalability ### Current Metrics * **Response Time**: 300ms POS, 200ms mobile * **Throughput**: 100 tx/sec POS demo * **Resource Usage**: 30% CPU (server), <50MB RAM (mobile) ### Scalability Considerations * Horizontal scaling via containerized server instances * QR scan UI performance optimization * BSV transaction batching for peak demand ## Maintenance & Support ### Monitoring * **Logs**: Managed via cloud log aggregation (server) * **Metrics**: POS dashboard; Expo performance tracker (mobile) * **Alerts**: Webhook alerts for failed QR verifications ### Troubleshooting | Issue | Cause | Solution | | -------------- | ----------------- | --------------------------- | | Invalid QR | Data corruption | User scan retry, regenerate | | Blockchain err | Connectivity loss | Fallback to local cache | ## Resources * **Repository**: [POS](https://github.com/bsv-blockchain-demos/digital-receipts-pos); [Mobile](https://github.com/bsv-blockchain-demos/digital-receipts-mobile) * **Business Documentation**: [Digital Receipts - Business Overview](/demos-and-onboardings/demo-solutions/demos/digital-reciept/business-digital-reciept.md) * **Demo Environment**: [Live demo](https://digital-receipts-us-1.bsvb.tech/) * **Support Contact**: \[Lead Blockchain Engineer] *** *For business context and ROI details, see:* [*Digital Receipts - Business Overview*](/demos-and-onboardings/demo-solutions/demos/digital-reciept/business-digital-reciept.md) --- # Agent Instructions This documentation is published with GitBook. GitBook is the documentation platform designed so that both humans and AI agents can read, navigate, and reason over technical content effectively. Learn more at gitbook.com. ## Querying This Documentation If you need additional information that is not directly available in this page, you can query the documentation dynamically by asking a question. Perform an HTTP GET request on the current page URL with the `ask` query parameter, and the optional `goal` query parameter: ``` GET https://hub.bsvblockchain.org/demos-and-onboardings/demo-solutions/demos/digital-reciept/technical-digital-reciept.md?ask=&goal= ``` `ask` is the immediate question: it should be specific, self-contained, and written in natural language. `goal` is optional and describes the broader end goal you are ultimately trying to accomplish on behalf of the user. GitBook uses it to tailor the answer towards what is most useful for that goal. The response will contain a direct answer to the question and relevant excerpts and sources from the documentation. Use this mechanism when the answer is not explicitly present in the current page, you need clarification or additional context, or you want to retrieve related documentation sections.