Senior Full Stack Developer (Node.js + React.js) – Debugging & Performance Optimization

We are looking for an experienced Senior Full Stack Developer (6+ years) to help debug, optimize, and stabilize a live mobile application used in production.

The application is built using:

Backend: Node.js, Express.js
Frontend: React.js (React Native concepts)
Database: MongoDB
Project Overview

Our mobile application is currently facing several production issues impacting user experience and performance. We need a highly skilled developer who can quickly identify root causes, fix bugs, and implement scalable solutions.

Key Responsibilities
Debug and fix issues in both frontend and backend code
Resolve duplicate data creation issues (orders, transactions, etc.)
Optimize slow API responses and improve performance
Fix app crashes and improve stability
Review and improve existing codebase for best practices
Implement proper error handling and logging
Ensure smooth communication between frontend and backend
Current Issues to Solve
App freezes during login
Duplicate orders being created
Slow API response times (2–5 seconds)
Occasional crashes when fetching user data
Mandatory Skills
Strong experience with Node.js and Express.js
Advanced knowledge of React.js (React Native is a plus)
Solid experience with MongoDB (queries, indexing, performance tuning)
Proven experience as a:
Backend Developer
Frontend Developer
Full Stack Developer
Strong debugging and problem-solving skills
Experience working on live/production application
Preferred / Bonus Skills
Experience with performance optimization and scaling
Knowledge of caching (Redis or similar)
Experience with API security (JWT, authentication, rate limiting)
Familiarity with logging/monitoring tools
Understanding of concurrency and race conditions
Experience with database transactions
What We’re Looking For
Someone who can quickly understand an existing codebase
Ability to think like a senior engineer and suggest improvements
Strong communication and ability to explain fixes clearly
Focus on writing clean, maintainable, production-ready code
Deliverables
Fixed bugs and stable application
Improved API performance
Clean and optimized code
Brief documentation of changes and improvements
Project Type
Short-term (with potential for long-term collaboration)
To Apply

Please include:

Relevant past projects (especially debugging or production fixes)
Your approach to debugging live applications
Availability and estimated turnaround time

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