Data Export CSV Export (Node.js) Excel Export (ExcelJS — recommended) Streaming Excel for Large Datasets Frontend CSV Parsing (Papa Parse) Python (openpyxl) Anti-Patterns | Anti-Pattern | Fix | |--------------|-----| | Loading all data into memory | Stream from DB cursor for large exports | | No Content-Disposition header | Always set for browser download | | Generating exports in request handler | Use background job for 10K rows | | No progress indication | Use WebSocket/SSE for large export progress | | Unescaped CSV values | Use library (csv-stringify, Papa Parse) | Production Checklist -…