Experienced Backend Developer for AI-Powered Video Conferencing Credit System

We're seeking a skilled backend developer to build a robust credit-based system for an AI-powered video conferencing platform. The system will manage user credits, track usage in real-time, and handle payments for a seamless user experience.

Key System Features:
- Design and implement a scalable credit-based backend system
- Develop real-time usage tracking and credit deduction mechanisms
- Integrate payment processing for credit top-ups
- Implement secure user authentication and credit management (We already have authentication endpoints)
- Ensure system scalability and performance optimization

Required Technologies:
- Database: MongoDB
- Payment Processing: Stripe
- Cloud Services: AWS (Lambda, Fargate)
- Containerization: Docker
- Backend Language: Python or Node.js (Java considered as a secondary option)

Required Skills And Experience:
- 3+ years of experience in backend development
- Strong proficiency in Python or Node.js
- Experience with MongoDB and designing NoSQL database schemas
- Familiarity with AWS services, particularly Lambda and Fargate
- Knowledge of Docker and containerization concepts
- Experience integrating Stripe or similar payment gateways
- Understanding of WebSocket technologies for real-time communications
- Solid grasp of security best practices for handling financial transactions

Preferred Qualifications:
- Experience with video conferencing or real-time communication platforms
- Familiarity with credit-based or usage-based billing systems
- Knowledge of AI service integrations

Project Scope:
1. Credit System Design:
- Implement a flexible credit system for users
- Allow for negative credit balances with configurable limits
- Design a system to prompt users for credit top-ups
2. Real-time Usage Tracking:
- Develop mechanisms to track AI usage in real-time
- Implement accurate credit deduction based on usage
3. Payment Integration:
- Integrate Stripe for secure payment processing
- Implement credit purchase and top-up functionality
4. User Experience:
- Design APIs for displaying current credit balance
- Implement notification system for low balance alerts
5. Scalability and Performance:
- Ensure the system can handle concurrent users and high transaction volumes
- Optimize database queries and API responses for performance
6. Security:
- Implement secure authentication for credit-related transactions
- Ensure PCI compliance for payment processing
7. Monitoring and Logging:
- Set up comprehensive logging for troubleshooting
- Implement monitoring for system health and usage patterns

Please include in your proposal:
- Your relevant experience, particularly with similar credit-based systems
- Your approach to designing scalable, real-time financial systems
- Any questions or clarifications about the project requirements
- Your estimated timeline and availability
- Examples of similar projects you've worked on (if available)

Ideal Candidate:
The perfect freelancer for this project should have extensive experience in backend development, particularly with creating PRODUCTION-READY credit-based systems. A solid understanding of real-time tracking systems and payment integrations is essential. The ability to design user-friendly interfaces, even for backend systems, will be highly appreciated.