zugferd-service/.sisyphus/notepads/zugferd-service/decisions.md

Decisions - zugferd-service

This file accumulates architectural and design decisions during execution.

[2026-02-04T18:12:44.864Z] Session Start

Planning decisions from Prometheus session.

Tech Stack

• Python 3.11+
• FastAPI for REST API
• Pydantic for data validation
• pytest for testing
• factur-x library for ZUGFeRD extraction
• pypdf for PDF text extraction

Scope Lock

• NO authentication (stateless service)
• NO database
• NO caching
• NO rate limiting
• 10MB file size limit
• 0.01 EUR tolerance for calculations

Validation Rules

• pflichtfelder: Required fields check
• betraege: Amount calculations check
• ustid: VAT ID format check (no online validation)
• pdf_abgleich: XML vs PDF text comparison