To: Qoder Development Team
From: Full-Stack Application Developer
Date: September 12, 2025
Subject: Critical Consistency Issues During Complex Application Development
Project Overview
I developed a comprehensive tax processing application using Qoder’s AI coding assistant with the following components:
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React frontend with authentication, dashboards, and form processing
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FastAPI backend with PostgreSQL database
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RPA automation for Excel file manipulation
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Complete PAYE tax return processing system
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Multi-user company profile management
Key Issues Encountered
1. Cascade Breaking Pattern
Problem: The AI consistently broke working features when fixing unrelated issues, despite explicit instructions to avoid touching other components.
Examples:
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Fixed logout button placement → Authentication endpoints stopped working
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Resolved file upload issues → PAYE profile confirmation disappeared
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Updated UI components → Existing imports and functions were deleted
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Authentication repairs → Schedule data display functionality removed
Impact: Every fix required 2-3 additional repair sessions, creating development regression instead of progress.
2. Authentication System Instability
Critical Issue: Authentication proved extremely fragile during development cycles.
Specific Failures:
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Registration flow suddenly redirecting to homepage instead of company profile
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Working login/register routes returning “Not Found” errors
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Session management breaking during unrelated UI updates
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Previously functional auth system failing after minor changes
This is particularly problematic since authentication is foundational - when it breaks, the entire application becomes unusable.
3. Context Loss and Poor Change Isolation
Problem: The AI failed to maintain awareness of component dependencies and made modifications outside specified scope.
Mitigation Attempts:
I developed structured prompts with explicit boundaries:
- "Modify ONLY file X, function Y"
- Detailed "DO NOT CHANGE" lists
- Verification checklists
- Single-file modification requests
Results: Prompts helped but didn’t eliminate the issue. Unintended modifications occurred ~60% of the time.
4. Development Time Impact
Time Analysis:
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Estimated 3-4 hours of debugging for every 1 hour of intended development
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Multiple days spent in fix-break-fix cycles
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Authentication issues alone consumed several full development sessions
Positive Aspects
Where Qoder Excels:
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Building new features from scratch
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Complex business logic implementation
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Database schema and migrations
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Comprehensive UI component creation
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Isolated feature development
The tool successfully helped create a sophisticated PAYE processing system with RPA automation - impressive technical achievement when components worked in isolation.
Comparison Context
Testing the same application concepts with other AI coding platforms showed this consistency issue isn’t universal, suggesting it’s a technical problem that can be addressed rather than an inherent AI limitation.
Technical Recommendations
High Priority Fixes
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Dependency Tracking: Analyze component relationships before making changes
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Change Scope Enforcement: Strictly limit modifications to specified files/functions
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Authentication System Protection: Special handling for critical infrastructure components
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Context Preservation: Maintain full application awareness during modification sessions
Development Process Improvements
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Conservative Change Policy: Default to minimal modifications
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Rollback Capability: Automatic reversion when changes break existing functionality
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Impact Analysis: Preview potential effects before implementing changes
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Test Integration: Basic functionality verification before confirming changes
User Experience Impact
The consistency issues significantly impact developer confidence in the tool for ongoing application maintenance. While Qoder excels at initial development, the unpredictability during iteration cycles makes it challenging for complex, interconnected applications.
Authentication system failures are particularly critical since they can render entire applications unusable late in the development process.
Conclusion
Qoder demonstrates strong capabilities for feature development but needs improved reliability for code modification and maintenance tasks. Addressing the consistency issues would substantially improve the development experience and make the platform more suitable for complex, production-ready applications.
The authentication stability issue should be treated as high priority since it affects the foundational functionality most applications depend on.
Based on extensive real-world development experience with a complex full-stack application
