Backend Developer Needed (Node.js/REST) – Social, Credit Transfer & Event APIs

We are looking for an experienced Node.js backend developer to connect and complete several pre-structured API endpoints for our mobile apps (iOS/Android) and admin dashboard. The endpoint structures are already created, your job is to connect them to our backend database, handle authentication/security, and ensure smooth functionality. Key Scope of Work Social System (Friends & Associates): Endpoint to fetch user friend lists (mobile & admin dashboard view). Logic to send, accept, and cancel friend requests (handling duplicate checks and self-requests). Logic to safely remove friends without affecting core user data. Credit Transfers (User-to-User): Endpoint to handle peer-to-peer balance transfers. Must include validation (checking sender balance, confirming recipient existence). Crucial: Needs atomic database transactions to prevent duplicate processing or race conditions. Event Tracking: Endpoint to receive and store mobile app events securely. Requirements & Skills Core Tech: Node.js, REST APIs, Database Management (Atomic Transactions/Locks). Security & Quality: Auth/AuthZ integration, input validation, clean logging, and proper error handling. Testing & Documentation: Thoroughly test endpoints and provide clear documentation/payload examples for our mobile developers. Deliverables Fully functional endpoints hooked to our existing DB and framework. Automated test cases covering successful and edge-case scenarios. API documentation for integration. How to Apply Please include: Examples of similar backend API projects (especially social or wallet/credit systems). Your estimated completion time.