Open to opportunities

Marcelo Xavier

@marceloxavier

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Tech Lead and backend engineer specializing in Ruby on Rails, scalable systems, and performance optimization.

Portugal

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What I'm looking for

I’m looking for leadership roles shaping backend architecture and performance in ambitious, collaborative teams, with opportunities to mentor engineers and work on large-scale systems.

I am a results-driven Tech Lead and Backend Engineer with over a decade of professional experience, specializing in Ruby and Ruby on Rails while working across microservice architectures. I have led backend development for large-scale workforce and attendance systems, improving performance and memory efficiency to produce highly stable services.

I’ve delivered full-stack and backend solutions for startups and enterprises—designing ETL pipelines, payment integrations, and internal automation tools—while contributing to distributed-systems research and multiple IEEE publications. I mentor engineers, define architecture, and drive measurable improvements in scalability and reliability.

I’m an active contributor to the Ruby community and continually expand my stack knowledge across Elixir, Go, Kotlin, Python and cloud platforms. I thrive in fast-paced environments where I can solve complex problems, improve system performance, and lead teams to deliver high-quality software.

Experience

Work history, roles, and key accomplishments

Current

Tech Lead / Backend Engineer

Current

Jobandtalent

Jan 2020 - Present (6 years)

Led backend development of core services used by millions across Europe, improved Rails service performance and memory efficiency, and defined architecture to ensure scalability and reliability across a mixed microservice platform.

Ruby on Rails Elixir Kotlin Go PostgreSQL Redis Sidekiq AWS Kubernetes

Full Stack Software Engineer

Toptal

Aug 2016 - Jan 2025 (8 years 5 months)

Delivered full-stack solutions to clients worldwide via the Toptal platform, providing engineering across frontend and backend stacks for diverse projects.

Ruby on Rails JavaScript PostgreSQL Docker CI CD AWS API Design Testing

Full Stack Software Engineer

Bitbond

Feb 2018 - Jan 2020 (1 year 11 months)

Built backend systems for a blockchain-based bond issuance platform, led a team for SME data processing, implemented ETL pipelines and SWIFT payment integrations to support loan origination.

Ruby on Rails Python AWS Lambda PostgreSQL Redis Sidekiq RabbitMQ Docker

Full Stack Software Engineer

Onfido

Jan 2017 - Oct 2017 (9 months)

Contributed to global identity-verification pipelines for enterprise customers, building internal tools to improve reliability, monitoring, and security across a distributed microservices architecture.

Ruby on Rails Elixir Python React Docker Kubernetes PostgreSQL Redis AWS

Full Stack Software Engineer

Resultados Digitais

Aug 2014 - May 2016 (1 year 9 months)

Developed internal and customer-facing tools for a SaaS marketing automation platform, improving keyword-tracking performance by 166× and refactoring signup flows to boost conversion.

Ruby on Rails AWS RSpec PostgreSQL Redis Sidekiq RabbitMQ CircleCi

Fullstack Software Engineer

Chaordic Systems

Jun 2013 - Jul 2014 (1 year 1 month)

Worked on an e-commerce personalization and email-marketing platform, scaling throughput from 500 to 2,500 requests per minute and improving operational efficiency by 66% through refactoring and DevOps automation.

Ruby Scala Python PostgreSQL MongoDB Redis Sidekiq RabbitMQ AWS

Distributed Systems Engineer

LAPESD / LISHA Labs

Jan 2011 - Dec 2013 (2 years 11 months)

Conducted research and system development in distributed and fault-tolerant computing, contributing to IEEE publications on Byzantine fault tolerance and completing an MSc in Computer Science.

Distributed Systems Fault Tolerance C C++Embedded Systems Research Linux Virtualization Byzantine Consensus

Full Stack Software Engineer / Scrum Master

OnCast

Jan 2008 - Dec 2013 (5 years 11 months)

Led agile full-stack development across 20+ consulting projects, built tools for MMOG and medical RFID applications, and implemented enterprise single sign-on and security solutions.

Java C++Python Ruby JavaScript MySQL PostgreSQL Unity3D

Education

Degrees, certifications, and relevant coursework

Federal University of Santa Catarina

Master's Degree, Computer Science

2011 - 2013

Activities and societies: Research at LAPESD/LISHA labs on Byzantine Fault Tolerance and virtualized distributed systems; IEEE publications including BAMcast.

Completed a Master's Degree in Computer Science with research on distributed and fault-tolerant computing, resulting in publications on Byzantine fault-tolerant consensus.