Lucas Antonio Ramos Sartori
Senior Backend Engineer | Ruby on Rails | PostgreSQL | AWS | APIs, Performance & Scalability | AI Integrations
Senior Software Engineer with nearly 9 years of experience, focused on building, evolving, and scaling Ruby on Rails applications for U.S.-based and international companies. Strong background in legacy systems, multi-tenant architectures, APIs, AI-driven features, and long-term maintainability.
Professional Experience
Senior Backend Ruby Developer
Ballast Lane Applications · Remote · USA · Sep 2024 – Present
Backend engineer across multiple client products — event-driven systems, legacy modernization, and AI-driven workflows.
Syncro
- Integrated business management platform for service providers.
- Built ElasticSearch + Karafka event-driven indexing pipeline, reducing database load and improving search performance.
- Implemented RSpec CI pipelines with 80%+ minimum coverage (most repos above 90%).
TripleSeat
- Large-scale event and restaurant management platform.
- Redesigned prompts from 4k+ lines to ~450 using modular architecture — 60% Gemini cost reduction with better results.
- Redesigned duplication detection service: timeouts dropped from 4–20+ min down to 1–4 min.
- Applied prompt engineering and generative AI for reliable automation workflows.
Inspect Point
- 10+ year multi-tenant legacy system.
- Designed REST APIs and owned backend integrations (internal + third-party).
- Created team CI enabling RSpec adoption — coverage grew to 50%+.
- Fixed performance and security issues: N+1, mass assignment, SQL injection.
Senior Software Engineer
FullStack Labs (NoFraud) · Remote · USA · Nov 2021 – Mar 2024
- High-volume e-commerce fraud detection platform.
- Rebuilt merchant dashboards, reporting systems, and document upload workflows.
- Integrated Brakeman and fixed security vulnerabilities.
Key Achievements
- Led dashboard rebuild.
- Increased test coverage from 2% to 40%+.
- Built integrations with BigCommerce and Adobe Commerce.
- Fixed N+1 queries, mass assignment, and SQL injection vulnerabilities.
Senior Software Engineer / Tech Lead
Grupo EUAX · Remote · Brazil · Dec 2020 – Nov 2021
- Led development of Twygo, a 10+ year online education platform.
- Ruby on Rails specialist and technical reference for a team of 4.
- Balanced feature delivery with refactoring and legacy system stability.
Key Achievements
- Resolved N+1 queries, mass assignment, and SQL injection across the codebase.
Fullstack Developer
Lets · Hybrid · Brazil · Apr 2019 – Nov 2020
- Delivered projects for startups, NGOs, and enterprises using Rails, Angular, Vue, and Node.js.
- Built SPAs, REST APIs, and mobile apps (Flutter, NativeScript, Kotlin).
Android Developer
Stape Music · Remote · Sep 2018 – Apr 2019
- Kotlin music streaming app — features, bug fixes, and musician monetization workflows.
Fullstack Developer
Teorema Sistemas · Guarapuava · Brazil · Jun 2017 – Sep 2018
- ERP system with Spring Boot, Angular, and Kotlin.
- Rewrote backend from JEE to Spring Boot and mobile app from Java to Kotlin (MVVM, Retrofit, Realm).
Key Achievements
- Fixed N+1 performance issues across the system.
- Reduced offline sync time from ~4 hours to 10–15 minutes.
Education
Specialization in Mobile Web Application Development
UniGuairacá Centro Universitário · 2019 – 2021
Bachelor in Internet Systems Technology
Federal University of Technology · 2014 – 2019
Certifications
Microsoft Certified: Azure AI Engineer Associate
Microsoft · 2025
Designs and implements AI solutions on Azure — including Azure OpenAI, Cognitive Services, and ML pipelines — with focus on responsible AI, data grounding, and production-ready integrations.
Side Projects
uButeco
Open-source platform to manage restaurant orders, inventory, and kitchen panels, featuring real-time updates, role-based access, and customizable UI.
Ruby on Rails · PostgreSQL · Angular · Angular Material · NgRX · JWT · REST APIs
Recommendations
“Lucas is a strong developer, hardworking, and a great collaborator. He consistently goes the extra mile to deliver quality work.”
“Lucas is not only a competent Ruby developer, but also brings positivity and energy to the team. A pleasure to work with.”
“Extremely committed, he always gives his best and has a great desire to learn. He's the kind of person who's truly dedicated; we can always count on him for anything.”