Courier Verification System (CVS)
Private Client - Logistics Outlet Tool
A local, self-hosted replacement for a discontinued proprietary courier verification app (掌中通). Built for small logistics outlets to securely import Excel/CSV/TXT pickup data (primarily in Chinese), normalize and store records, perform manual or bulk verification based on name + phone last-4, prevent duplicates/reuse, and maintain complete audit logs. Features multi-language support (Chinese and English), simple operator accounts with roles, and runs entirely on the user's PC or local server without external dependencies, subscriptions, or biometrics.
Next.jsJavaScriptTailwind CSSFastAPIPostgreSQLSQLAlchemypandasopenpyxlJWT
Impact & Results
- Replaced fragile emulator-based workflow with stable local system
- Enabled reliable bulk verification of thousands of records
- Provided full audit trail and operator accountability
- Supported Chinese data and UI while adding English localisation
Architecture
- Backend: FastAPI with PostgreSQL (SQLAlchemy ORM) for API and data persistence
- Frontend: Next.js (JavaScript) with Tailwind CSS for responsive multi-language UI
- File import: pandas + openpyxl with intelligent Chinese header mapping and data cleaning
- Authentication: Session-based with role checks (admin/verifier)
- Atomic verification transactions and comprehensive audit logging
Challenges
- Handling messy real-world imports (Chinese headers, spaces, masked phones, varying formats)
- Ensuring concurrency safety for multiple simultaneous operators
- Supporting both Chinese and English interfaces seamlessly
- Designing robust deduplication and atomic verification logic
Solutions
- Dynamic header mapping dictionary + manual override for Chinese column names
- Database transactions and unique constraints for safe concurrent verification
- i18n implementation in Next.js with fallback to English
- Import-time cleaning and batch-scoped uniqueness checks
Key Takeaways
Building production-ready self-hosted systems with zero external runtime dependencies
Effective handling of multilingual data and UI in real-world applications
Importance of atomic operations and audit trails in logistics/verification systems
Balancing flexibility and strictness in data import pipelines
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