Senior Full-Stack Engineer - Contract (15+ Years)

Fabio William Conceição

Senior Full Stack / Software Engineer (Contract)

Email: **********@******.**

GitHub: https://github.com/Messhias

SUMMARY

Senior Software Engineer with 15+ years of experience building, maintaining, and scaling backend systems and APIs in production environments. Strong background in Golang, PHP, distributed systems, REST APIs, databases, and cloud infrastructure. Highly autonomous, delivery-focused, and experienced in remote, contract-based work with international teams.

Comfortable working on existing codebases, improving performance, fixing critical issues, and delivering reliable solutions with minimal supervision and meetings. CORE SKILLS

● Golang, PHP, C#, Python, ReactJS, Flutter and NextJS

● API Design: REST, JSON, authentication, performance tuning

● Databases: PostgreSQL, MySQL, MongoDB

● Cloud & Infra: Docker, Linux, AWS, Azure, NGINX

● Architecture: Monoliths, microservices, legacy refactoring

● Tooling: Git, CI/CD, Terraform

● Remote Work: async communication, independent delivery PROFESSIONAL EXPERIENCE

Senior Software Engineer

Various

Jan 2008 – Present

● Delivered backend systems and APIs for multiple clients across different industries

● Designed, maintained, and optimized production systems with high traffic and strict reliability requirements

● Worked independently on architecture decisions, bug fixing, refactoring, and performance improvements

● Integrated third-party services, payment gateways, and internal tools

● Operated fully remote with minimal meetings and high delivery autonomy Golang Developer (Contract)

OLX Portugal — Remote

May 2025 – Aug 2025

● Developed and maintained backend services using Golang

● Worked on distributed systems within the OLX Group ecosystem (automotive platforms)

● Contributed to infrastructure provisioning using Terraform

● Supported monitoring and observability initiatives

● Collaborated asynchronously with cross-functional teams Senior Software Engineer

Collegia / FreePayroll — Remote (UK)

Feb 2020 – May 2025

● Built and maintained a mission-critical SaaS payroll system

● Developed high-performance APIs using Golang, GORM, Fiber

● Optimized concurrency and processing workflows under heavy load

● Delivered reliable, low-error systems used in real-world financial operations

● Worked closely with product and engineering teams in a remote setup Focused primarily on backend development, system reliability, and long-term maintainability.

Senior Full Stack Engineer / Architect (Contract)

ViaMe.ae — Remote

Jul 2019 – Feb 2020

● Designed and developed backend services and APIs

● Built and maintained applications using PHP, Node.js, and React

● Integrated payment gateways and third-party services

● Deployed and maintained systems on AWS

Additional Contract Roles

Senior Software Engineer — InQuesti (Remote)

Ruby, Python, React, Docker

Senior Python Engineer — CGV Cinemas (Contract)

Python, MySQL, API maintenance

Senior PHP Developer — Multiple Contracts

Laravel, CodeIgniter, MySQL, React

Long-term experience working with legacy systems, refactoring, and incremental modernization.

FreePayroll

● High-traffic payroll and financial systems

● E-commerce platforms

● Internal enterprise tools

● API-driven platforms and integrations

WORK STYLE

● Strong focus on delivery and reliability

● Comfortable owning tasks end-to-end

● Minimal supervision required

● Async-first communication

● Prefer clear scope and defined responsibilities

AVAILABILITY

● Contract / Freelance

● Part-time or full-time remote

● EU / US timezone overlap

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