Hello, I'm
Patrick Cunha
Belém, Pará, Brazil
About Me
Fullstack software engineer with nearly 14 years of experience specializing in scalable architecture and high-availability systems. Deep expertise in backend development with NestJS, Node.js, and Express, applying DDD, Onion Architecture, and SOLID principles. Proven track record in real-time communication systems, observability stacks, privacy-first AI integration with local LLMs, and full-stack delivery across healthtech, fintech, and SaaS domains.
Languages
Skills & Technologies
A broad stack built through 14 years of hands-on enterprise and product development
Backend
Architecture
Databases
ORM & Query Builder
Cloud & DevOps
AI & Automation
Frontend
CSS Frameworks
Mobile
Testing
Integrations
Work Experience
A decade of building scalable systems across four continents
Sr. Full Stack Engineer
Nexton (client: Trellisrx)
- Designed WebSocket service with NestJS + Socket.io — 94% reliability improvement
- Built observability stack (Grafana + Promtail + Loki) — ~60% MTTR reduction
- Benchmarked Llama, Mistral, Qwen, and DeepSeek via Ollama — selected best model per use case against available hardware
- Optimized MySQL/MongoDB query patterns — ~40% response time reduction
- Reduced CI/CD deploy time by ~50% via Jenkins JCasC optimizations
Lead Full Stack Engineer & Product Engineer
EsimFacil
- Built Next.js landing page — 47% lift in lead conversion, Core Web Vitals 97%
- Implemented transparent checkout flow with Pagar.me via serverless functions
- Built AI after-hours chatbot with n8n, Redis, and vector knowledge base
- Led two junior developers; automated Vercel deploys via GitHub Actions
Lead Full Stack Engineer
Alfaconsul
- Designed entire backend from scratch with NestJS, DDD, and Onion Architecture
- Developed high-performance SSR dashboard with Next.js and Atomic Design
- Engineered React Native app mirroring dashboard architecture
- Architected AWS RDS (PostgreSQL) + MongoDB data layer
Sr. Backend Engineer
Jamango
- Led migration of backend from Ruby on Rails to NestJS
- Introduced LocalStack for AWS service emulation (S3, SSM)
- Built data layer with PostgreSQL and TypeORM
Lead Full Stack Engineer
Virgo Solutions
- Led development of AI-powered product management tool with OpenAI integration
- Built multi-repo management across GitHub, GitLab, CodeCommit, and Bitbucket
- Managed AWS cloud infrastructure: Cognito, S3, EC2, RDS, DynamoDB, Lambda
Sr. Software Engineer — Backend
Maitha Tech
- Designed modular white-label e-commerce API with NestJS for multi-tenant scalability
- Implemented event streaming with Kafka and MongoDB for high-throughput resilience
Sr. Software Engineer — Full Stack
Appgami
- Developed monday.com and Azure DevOps integration features
- Built serverless functions with Firebase Cloud Functions
Mid Backend Engineer
Zenklub
- Migrated microservices from legacy architecture to Serverless/Node.js on AWS Lambda
- Introduced NestJS to modernize service architecture
Mid Frontend Developer
Conaz
- Enhanced React-based platform UIs and resolved cross-browser compatibility issues
- Implemented microservices via Firebase Cloud Functions
Junior Backend Engineer
BitX
- Developed and maintained RESTful APIs with Node.js, Express, and MongoDB
- Built payment gateway integrations using Electron and C#
Junior Full Stack Engineer
Kronos – Tecnologia & Informação
- Designed and implemented enterprise web management systems
- Managed and maintained Linux servers
Desktop Developer Intern
Banco do Brasil
- Automated internal workflows with VBA macros, reducing manual processing time
- Enhanced internal systems with PHP integrations
Projects
All work is under corporate NDA/IP agreements — case studies highlight impact and approach
Real-Time WebSocket Communication System
Healthcare SaaS platform serving hundreds of concurrent clinical users
Critical race conditions causing synchronization failures across multi-client sessions, leading to data inconsistencies
Designed WebSocket service from scratch using NestJS + Socket.io with proper concurrency control and event-driven architecture
94% improvement in WebSocket reliability; eliminated synchronization failures in production
Privacy-First Local LLM Infrastructure
Healthcare platform needing AI-powered features without exposing proprietary or patient data to third parties
External AI APIs posed compliance and IP risks for sensitive medical data
Deployed on-premise LLM stack with Ollama, benchmarking Llama, Mistral, Qwen, and DeepSeek models against available hardware to find the best performance/resource trade-off for each use case
AI-powered code generation, data analysis, and diagnostic assistance — with zero external data exposure
Observability & Log Monitoring Stack
High-traffic production system with slow incident response and no centralized logging pipeline
High mean time to resolution (MTTR) due to fragmented, unstructured server logs across multiple services
Implemented Grafana + Promtail + Loki pipeline for real-time log ingestion, alerting, and analysis
~60% reduction in MTTR; production incidents diagnosed in seconds instead of hours
High-Conversion SaaS Landing Page
Early-stage eSIM startup without an online presence or lead capture mechanism
Zero web presence, poor Core Web Vitals, and low lead conversion rate
Built Next.js landing page with heatmap-driven UX (Microsoft Clarity), on-page SEO, and CTA optimization
47% lift in lead conversion; Core Web Vitals performance score reached 97%
AI-Powered Multi-Repository Manager
SaaS product for engineering teams managing issues across multiple VCS platforms simultaneously
Manual overhead triaging and tracking issues across GitHub, GitLab, and Bitbucket caused delays
Full-stack app with OpenAI integration for automated issue triage and PR suggestions across all platforms
MVP delivered and validated; significantly reduced manual repository management overhead for teams
White-Label Multi-Tenant E-Commerce API
Platform serving multiple retail brands on a single shared backend infrastructure
Architecture needed complete tenant isolation while efficiently sharing compute resources
Modular NestJS API with Kafka event streaming and MongoDB, designed for independent brand configurations
Scalable multi-tenant system enabling rapid onboarding of new retail brands
Education
Bachelor's Degree in Computer Science
Federal University of Pará (UFPA)
Languages
Get in Touch
Open to senior engineering roles and interesting technical challenges
Based in Belém, Brazil — available for remote positions worldwide. Feel free to reach out for engineering roles, consulting, or technical discussions.