Patrick Leandro de Sá

Fullstack Developer & Solutions Architect 👨‍💻

I help startups and businesses worldwide ship reliable, scalable software and modernize legacy systems — from architecture decisions to production deployment.

I don't just write code — I think about performance, cost efficiency, and long-term maintainability. Whether it's a mobile app, a REST API, or a complex backend system, I focus on solutions that actually work in production: optimized queries, caching strategies, global deployments, and clean architecture.

🎯 What I bring to the table: → 🛠️ Custom software tailored to real business needs → ⚙️ Process automation that eliminates operational bottlenecks → 🔄 Legacy system refactoring — modernizing old codebases without breaking what works → ⚡ Production-grade mindset: performance, observability, and cost-aware infra → 💬 Clear communication and technical leadership from architecture to delivery

🧠 Expertise

Performance optimization — profiling, query tuning, and response time reduction
Cost-aware architecture — right-sizing infra and reducing cloud spend without sacrificing reliability
Global deployments — CDN strategies, multi-region setups, and edge functions
Caching strategies — Redis, HTTP caching, and database query caching
Efficient code — avoiding over-engineering, keeping complexity low and maintainability high
Observability — logs, metrics, and alerting so issues surface before users notice
Process automation — internal and operational workflows
Bottleneck identification and translation into code
Legacy system refactoring — modernizing old codebases without breaking what works
SaaS, PaaS, ERP, and CRM platform development
API integrations and payment systems (Cielo, Stripe, MercadoPago)
DevOps & scalable infrastructure with AWS, GCP, CI/CD, Docker

🎯 My Focus

Building systems that boost business efficiency using best practices in architecture and code quality:

🧪 TDD (Test-Driven Development) for reliability and coverage
🧩 DDD (Domain-Driven Design) to reflect real business logic
🏗️ SOLID & Clean Architecture applied to critical systems
🧠 Robust and scalable data modeling
🗂️ Technical planning and development leadership
🛠️ Solid, secure, and high-performance back-end
🎨 Front-end crafted for the best user experience (UX)

🔧 Main Stack

Back-end: Node.js · Bun · NestJS · FastAPI · Laravel · Python
Front-end: React · Next.js · Svelte & SvelteKit · Vue · Tailwind CSS
Mobile: React Native / Lynx
Databases: PostgreSQL · MySQL · MongoDB (Prisma / Drizzle / SQLAlchemy ORM)
DevOps: AWS · GCP · Docker · GitHub Actions · CI/CD
Unit Testing: Jest · Vitest · Pytest
E2E Testing: Playwright

💼 Hands-On Experience

Executable automation solutions using Python
Software development for startups and companies of various sizes
Technical leadership from architecture to delivery
Legacy system refactoring and modernization
Custom ERP, CRM, SaaS, and PaaS systems for real business needs

🔗 Integrations & Automations

Payment gateways (Cielo, Stripe, MercadoPago)
External APIs and legacy systems
Custom bots and scripts for workflow automation

🧩 Professional Qualities

🎯 Strategic planning and task organization
🗂️ Scalable architecture with a long-term maintenance focus
💬 Clear communication and stakeholder alignment
🚀 Turning ideas into real, working products

📫 Get in Touch

🌐 Website: patrickleandrodev.vercel.app
💼 LinkedIn: linkedin.com/in/patrick-leandro-de-sa
📧 Email: patrickleandrodesa@gmail.com

⭐ Ready to turn your ideas into impactful products? I'll help you build real solutions — well-planned and developed with technical excellence. Let's talk! =)