ETEP — Escola Técnica Professor Everardo Passos
2009 — 2011High School and Computer Technician
AI-assisted · TypeScript · Node.js · React · AWS
Senior Software Engineer
Leonardo Sarmento de Castro
São José dos Campos, São Paulo — Brazil 🇧🇷
Senior Software Engineer with 10+ years of experience building scalable, high-performance web applications and distributed systems using JavaScript, TypeScript, React, and Node.js. Experienced working closely with US product teams to deliver measurable improvements in performance, conversions, developer experience and product adoption.
About
I work with AI-assisted tooling as a natural part of my workflow, and bring that same pragmatic approach to everything I ship.
I take ownership of what's in front of me, stay focused on outcomes and move fast without cutting corners.
I care deeply about the craft and about the people I build with. I show up with discipline and accountability, and I do my best work in environments where quality, communication and collaboration are taken seriously.
Work Experience
Aug 2026
Aug 2026
❓2026 — Looking for new opportunities.
Aug 2024 — May 2026
Jan 2025 — Jun 2025
Jun 2024 — Dec 2024
Jun 2021 — Jun 2024
Dec 2023 — May 2024
May 2022 — Aug 2023
Nov 2021 — Apr 2022
👔2021 — Career shift: now working remotely as a contractor. Prioritizing clients from the US and EU.
Sep 2020 — Feb 2021
Dec 2017 — Dec 2019
⭐2017 — Career achievement: working abroad. VISA sponsored to live and work in Berlin, Germany, by a leading global dating company with more than 1 million active monthly subscriptions.
Jul 2016 — Oct 2017
Feb 2016 — May 2016
🎉2016 — Ascended to senior level developer, defining Node.js as a career mastery goal. Kept working in multidisciplinary environments with Ruby on Rails and JavaScript.
Jul 2015 — Dec 2015
Feb 2015 — Jul 2015
Jun 2014 — Nov 2014
🎉2014 — Ascended to mid level developer, working in multidisciplinary environments with Java, Ruby on Rails and JavaScript.
Jun 2013 — Jun 2014
🎉2013 — Ascended to junior developer, now working as a full stack web developer with Java.
Jan 2012 — Jan 2013
⛳2012 — Acquired first job as Intern, working in web applications with C# and JavaScript.
Education
Skills
Communication
EnglishAdvancedSpoken · Written9 years · 2017 until now●●●●●●●●●○
PortugueseExpertNative · Spoken · WrittenNative speaker
AI
Runtimes
Languages
Frameworks
Databases
Infrastructure
CMS
Design
Get in Touch
MESSAGE ME on WHATSAPP+55 (12) 98127-6618SEND ME an EMAILhi@leonardosarmentocastro.comMESSAGE ME on LINKEDIN
Current time for me is (GMT-3)