Nadson Alex - Fullstack Developer specialized in Node.js, React and TypeScript

Jul 2026 → Present

• ▸Lead developer of a Node.js, Fastify and PostgreSQL application, owning problem investigation, solution design, implementation and technical evolution
• ▸Built the file import, upload and download flow with Fastify Multipart, streams and AWS S3, handling large files without loading them fully into memory while keeping authentication and authorization on the backend
• ▸Implemented async processing with BullMQ and Redis, using workers, scheduled jobs and retries to make background operations more resilient
• ▸Implemented authentication with JWT in HttpOnly cookies and RBAC authorization, with permissions updated live during active sessions so role changes apply without a new login
• ▸Own the full delivery cycle, from development to deployment with Docker, Nginx, GitHub Actions, VPS and AWS
• ▸Set up Grafana dashboards, metrics and alerts to monitor 300+ virtual machines, and investigate production incidents from those dashboards and log analysis

Feb 2026 → Jul 2026

• ▸Built 40+ multi-tenant REST endpoints with Node.js, Fastify, TypeScript and Zod, with tenant isolation and centralized error handling, serving over 10,000 requests/day
• ▸Modeled the relational architecture in PostgreSQL and optimized queries with Knex.js and raw SQL, using JOINs and aggregations for analytical reports
• ▸Cut PostgreSQL load with Redis caching (ioredis) across 30+ features, improving response times
• ▸Contributed to an internal library of 25+ React components (Radix UI, TailwindCSS, React Hook Form and Zod), removing duplication across 15+ screens
• ▸Raised test coverage from 12% to 67% with unit, integration and end-to-end tests (Vitest, Jest and Supertest)

Jul 2025 → Feb 2026

• ▸Automated 18+ processes with a Python CLI (Typer, Paramiko, Pydantic), saving 120+ hours/month - tasks of up to 6 hours now take about 30 minutes
• ▸Maintained 300+ Linux virtual machines (Ubuntu and CentOS), sustaining availability above 97%
• ▸Managed 200+ network configurations with Nginx and VyOS (reverse proxy, DNS, NAT and port forwarding)
• ▸Built automated backups for 30+ Linux systems and Docker environments, and diagnosed production incidents with systemctl, journalctl, netstat and log analysis

May 2026 → Present

• ▸Built 20+ responsive screens with Next.js, React 19, TypeScript and Shadcn/UI (dashboards, scheduling, medical records and settings), using React Query, Zustand and forms validated with React Hook Form + Zod
• ▸Designed a multi-tenant NestJS REST API with 110+ routes across 25+ modules, applying object-oriented design, dependency injection and a modular architecture, documented with Swagger
• ▸Implemented permission-based authorization (RBAC) with custom Guards and Decorators, isolating each clinic's (tenant's) data and controlling each professional's access to patients
• ▸Modeled 20 tables and 12 enums with Prisma ORM and PostgreSQL, with 21 migrations, soft delete and N:N relationships between users, patients and organizations
• ▸Set up async processing with BullMQ and Redis queues in a worker separate from the API, with exponential-backoff retries, scheduled jobs and graceful shutdown under PM2
• ▸Built queue-processed file uploads to Cloudflare R2 (S3 API), validating the real file type by magic bytes, with SHA-256 checksums and downloads via presigned URLs