---
title: Always Validate Client Data Server-side
impact: MEDIUM
impactDescription: ensures input validation cannot be bypassed
tags: validation, server-side, input, sanitization, security
---

## Always Validate Client Data Server-side

This rule ensures high quality and security in Python and PySpark applications.

**Implementation Guidance:**
- Follow standard Python best practices (PEP 8)
- Use type hints for better clarity
- For PySpark, prefer DataFrame API over SQL strings where possible
- Ensure proper resource management (using \`with\` statements)