Open to opportunities

fernando limeira

@fernandolimeira

Message

I modernize secure, high-performance Java and Node.js backend systems for enterprise products.

Canada

Message

I've built and modernized enterprise backend systems across CaRMS, ThinkOn, Iteris, Indra, and Unimed. At CaRMS, I designed authentication and SSO solutions and reduced legacy login response time from approximately 1.6–1.8 seconds to 75–150 milliseconds across more than 1,200 validated login scenarios.

I build production-focused Java, Spring Boot, Node.js, and TypeScript services, including asynchronous Stripe payments with RabbitMQ, DynamoDB migrations, REST and SOAP APIs, and secure OAuth 2.0/OIDC authorization. I also develop independent SaaS and AI-powered products using React, Java 21, Spring Boot, PostgreSQL, Docker, and role-based access control.

Experience

Work history, roles, and key accomplishments

Current

Independent Project

Current

AI-Powered Gym Assistant

Jan 2025 - Present (1 year 7 months)

Developed an AI-powered gym assistant using React, Java 21, Spring Boot, and Gemini function calling/tool use for workout-plan and exercise workflows.

React Java 21+Spring Boot Gemini AI Function Calling

Current

Independent Project

Current

Multi-Tenant Farm Management SaaS

Jan 2025 - Present (1 year 7 months)

Developed a multi-tenant farm management SaaS using React, Java 21, Spring Boot, PostgreSQL, Docker, tenant-aware service boundaries, and role/capability-based access control.

React Java 21+Spring Boot PostgreSQL Docker Multi Tenant Services Access Control

Senior Java Engineer

CaRMS

Feb 2025 - Jun 2026 (1 year 4 months)

Designed authentication and SSO solutions using AWS Cognito, Spring Authorization Server, OAuth 2.0/OIDC, JWT, and secure session patterns. Reduced legacy login response time from approximately 1.6–1.8 seconds to 75–150 milliseconds across more than 1,200 validated login scenarios.

Java Spring Boot Spring Security Cognito OAuth OIDC JWT API Gateway BFF Token Exchange Session to Token Migration React Oracle AWS

Senior Java Engineer

ThinkOn Inc.

Apr 2023 - Dec 2024 (1 year 8 months)

Designed a reusable proxy API for historical logging across Jersey- and Spring-based services. Built an asynchronous Stripe payment integration using RabbitMQ, isolating payment processing from core workflows and improving failure handling.

Java Jersey RabbitMQ Stripe REST APIs Microservices

Backend Engineer

Iteris

Oct 2021 - Apr 2023 (1 year 6 months)

Migrated transaction storage from AWS S3 to DynamoDB within a serverless Node.js architecture. Developed TypeScript REST endpoints with validation, structured error handling, reusable service components, and API tests.

Node.Js Development TypeScript S3 DynamoDB REST APIs Serverless API Testing Test Coverage

Senior Java Engineer

Indra

Apr 2020 - Oct 2021 (1 year 6 months)

Developed a Neo4j proof of concept for telecommunications network relationships and feasibility assessment. Implemented REST and SOAP services aligned with TM Forum standards; coordinated sprint planning and delivery with Telefonica stakeholders.

Java Neo4j REST SOAP Sprint Planning Stakeholder Management

Senior Java Engineer

A.C. Paz Construction

May 2018 - Dec 2019 (1 year 7 months)

Built a mobile-enabled clock-in/clock-out solution using geolocation, replacing manual spreadsheet-based time tracking. Implemented OAuth 2.0 authentication with Spring Security and AWS S3 photo uploads for field workers.

Java Spring Security OAuth S3 Geolocation Mobile Development

Java Engineer

Unimed Fortaleza

Mar 2010 - Dec 2017 (7 years 9 months)

Developed ERP, financial, SSO, reporting, and release-automation capabilities using Java, Spring, JSF, Oracle, and PL/SQL. Built a release automation tool integrating SVN, Jira, and Archiva, reducing release cycles from two weeks to two days.