Fernando Limeira | Full-Stack Software Engineer

Backend-focused engineer building secure, maintainable, and scalable software.

I work across backend and full-stack delivery, with hands-on experience in authentication modernization, payment integration, multi-tenant SaaS design, and AI-enabled products. I enjoy turning complex requirements into clear technical decisions and dependable implementation.

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Core focus

Backend, integrations, and full-stack product delivery

What I bring

Technical ownership, pragmatic architecture, and clear communication

Quick Proof

A concise view of the work I want to be hired for.

  • Authentication modernization with AWS Cognito and OAuth2/OIDC
  • Stripe payment integration for a multi-tenant platform
  • Multi-tenant SaaS design with PostgreSQL Row-Level Security
  • AI integration with Spring Boot and Gemini

Experience Overview

Professional experience, reduced to the parts that matter most.

This home page is intentionally short. These highlights show the kind of product and backend work I can contribute from day one.

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CaRMS

Software Engineer

Authentication modernization initiative

Contributed to the authentication modernization of a platform that supports the national medical residency matching process, where security and reliability were critical.

  • Researched AWS Cognito and modern OAuth2/OIDC flows, then evaluated integration patterns against existing system constraints.
  • Built proof of concepts, documented trade-offs, and presented options that helped reduce uncertainty before implementation.

ThinkOn

Full-Stack Developer

Payment integration project

Worked on a payment integration initiative for a multi-tenant platform as the company introduced a self-payment capability.

  • Designed and implemented a Stripe integration service after studying payment flows and mapping them into the platform architecture.
  • Created a reusable endpoint pattern for logging, persistence, and execution flow, making payment-related services easier to extend and troubleshoot.

Selected Projects

Personal projects that reinforce product and architecture depth.

I use personal projects to go deeper into system design, AI integration, and multi-tenant architecture beyond day-to-day delivery work.

Personal project

AI-Powered Gym Training System

A workout management application built to explore how LLMs can be connected to real product data and actions, not just wrapped in a chatbot UI.

Architecture angle: Built CRUD flows plus a conversational layer backed by Java and Spring Boot with Gemini, using hexagonal architecture so the AI provider could be replaced later.

  • Java
  • Spring Boot
  • Gemini
  • Hexagonal architecture

Personal project

Multi-Tenant SaaS for Egg Production

A SaaS product for farmers designed to explore tenant isolation, service boundaries, and maintainable multi-tenant architecture.

Architecture angle: Built a React frontend with a Java and Spring gateway plus backend services, using PostgreSQL Row-Level Security to enforce tenant data isolation.

  • React
  • Java
  • Spring Security
  • PostgreSQL RLS

Contact

Let's talk about backend, full-stack, or product-focused engineering opportunities.

Open to backend, full-stack, and product-focused engineering opportunities.

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