We are seeking skilled Golang backend developers to assist in rebuilding our current PHP website. This project involves transitioning existing functionalities to a more efficient and scalable backend using Go-lang. The ideal candidates will have experience in both PHP and Golang, with a strong understanding of backend development and integration. Not Agency. Only individual Freelancer. Project Deliverables 1. Codebase Audit & Technical Report Conduct a full review of the existing Go billing microservice. Identify bugs, missing logic, and architectural weaknesses. Deliver a written audit report outlining: Current system flaws Security or compliance concerns Clear recommendations for fixes and improvements 2. Stabilized Billing & Subscription Logic Refactor and fix all issues related to: Subscription creation Renewal and rebilling flows Cancellations and refunds Entitlement updates (premium access on/off) Ensure all state transitions are consistent and idempotent. Confirm that users are never billed after cancellation and never retain access after failed rebills. 3. Reliable Payment Provider Integrations Verify and finalize MobiusPay (NMI) and CCBill integrations. Ensure all webhook endpoints: Validate provider signatures Handle all relevant events correctly Update internal records accurately Test all webhook event types (success, fail, refund, cancel). 4. Reconciliation System Implement a reconciliation process (cron job or scheduled worker) that: Periodically fetches transaction data from payment providers Compares it against internal subscription records Flags mismatches or missing events for manual review Include simple reporting or logging for discrepancies. 5. Database & Data Integrity Improvements Review the existing PostgreSQL schema. Clean up migrations and ensure smooth deployment process. Enforce constraints, indexing, and relationships for reliability. Optionally advise or execute database separation (dedicated billing DB) for better modularity. 6. Integration Testing Suite Implement end-to-end integration tests simulating: New subscription payment success entitlement activation Renewal success/failure flows Cancellation and refund flows Use mocked MobiusPay/CCBill webhooks to simulate provider behavior. Ensure tests can run automatically in CI (GitHub Actions, etc.). 7. Deployment & Documentation Prepare the billing microservice for production deployment (Dockerized). Deliver updated README / setup documentation, including: Environment setup API routes and payload formats Webhook endpoints and sample payloads Reconciliation and testing instructions Final Deliverables Summary # Deliverable Output 1 Code audit report Written document outlining issues and fixes 2 Refactored billing system Stable Go service ready for deployment 3 Webhook reliability Fully tested and verified event handling 4 Reconciliation system Automatic job + discrepancy reporting 5 Database improvements Clean schema and stable migrations 6 Integration test suite Automated tests covering all workflows 7 Documentation Developer guide for deployment & maintenance