Part-Time Backend Engineer for Pre-Launch Review (AWS, Node.js, PostgreSQL)

I'm looking for a hands-on backend engineer with AWS and DevOps experience to independently review and prepare our backend for launch. The iOS and Android apps (Flutter) are built and in testing. The backend runs on AWS in the Frankfurt region, and our first users are in Jordan. We're targeting launch in December 2026. You'll work with our development team and hosting provider. Your role is to review, test, and verify. You'll identify issues and specify fixes, our development team implements them, and you confirm they're resolved. You'll only make changes directly where we agree on it in advance. Expected launch scale About 2,000 users in the first month. Load testing should target peaks of up to 800 concurrent users. Features include real-time chat (Socket.IO). Technical requirements Production experience with AWS, Node.js, Express, and PostgreSQL is required. Experience deploying and load testing Socket.IO or WebSocket messaging is a strong plus. Scope of work Phase 1: Review (fixed price or capped hours) - Review the AWS production setup: server and database sizing, load balancing, health checks, scaling, secrets management, and network security. - Review the backend code for security, reliability, and performance issues, including authentication and OTP endpoints, rate limiting, database queries and indexes, and connection handling. - Deliver a written report with findings ranked by priority (critical / high / low) and the recommended fix for each. Phase 2: Testing and launch support (hours agreed after Phase 1) - Run load and performance tests in a production-like environment for key flows: sign-up, verification, connection requests, and chat. Report traffic levels tested, response times, error rates, and bottlenecks. - Verify fixes with our development and QA teams. - Confirm monitoring and alerts work, test that backups can be restored, and rehearse deployment and rollback. - Provide a launch-readiness checklist and support production during an agreed launch window. Access and confidentiality The app handles sensitive personal data. You'll sign an NDA. Access is granted by phase: read-only for the review, staging for testing, and production only during the launch window. To apply, please share - An example of a mobile app launch you supported and what you personally handled. - Your experience with AWS production deployments, load balancing, and performance testing. - The top 3 things you'd check first on a new Node.js/PostgreSQL backend before launch. - A fixed price or estimated hours for Phase 1. - Your monthly quote for ongoing part-time support, including the hours per month it covers. - Your hourly rate, earliest start date, time zone, and weekly availability.