Hi, I'm
Raphael Sampaio
Senior React Native Engineer
Building mobile apps, web platforms and EdTech products that reach real users.
About me
I'm a Senior React Native Engineer with 8+ years of experience building mobile apps for iOS and Android. I've worked on fintech super-apps, mental health platforms, sports apps and EdTech products. I'm also the founder of Klog Academy, an EdTech app that teaches mathematics using the Singapore Math CPA method with sci-fi gamification.
I'm currently open to remote contractor roles with US-based companies.
📍 Fortaleza, CE — Brazil
✅ Available for remote work
💼 Remote contractor — US companies
Projects
Apps and platforms I've built or contributed to.
Klog Academy
Founder & Solo Engineer
EdTech app that teaches mathematics to children using the Singapore Math CPA method with sci-fi gamification. Built and launched solo from zero — available on App Store and Google Play.
Grão
Senior React Native Engineer
Brazilian fintech super-app with 250K+ downloads. Features include digital account, investments, transfers, and bank-grade security. Built with 80% test coverage.
Mindless Labs
React Native Engineer
Mental health mobile app focused on mindfulness, habit and emotional wellbeing. Available on both App Store and Google Play.
NodeKatas
Creator & Solo Engineer
Open-source browser-based interactive platform for learning Node.js. 30 exercises across 3 trails, running real Node.js via WebContainers. Supports 6 languages.
ReactJSKatas
Creator & Solo Engineer
Open-source browser-based interactive platform for learning React. 34 exercises across 4 trails including React 19. Uses Babel Standalone + iframe for live preview. Supports 6 languages.
WebKatas
Creator & Solo Engineer
Open-source browser-based interactive platform for learning HTML, CSS, Flexbox/Grid and JavaScript. 60 exercises across 4 trails. Supports 6 languages.
Matchday
React Native Engineer
Sports app for football fans — match schedules, live scores, team news and community features. Available on App Store and Google Play.
Skills & Tech
Technologies I work with.
Mobile
State & Data
UI & Styling
Testing & QA
Backend & Cloud
Tools
Certifications
Experience
Companies I've worked with over the years.
Klog Academy
Founder & Solo Engineer
04/2026 — Present
Built and launched an EdTech app from scratch teaching mathematics to children with Singapore Math CPA method and sci-fi gamification. Full product ownership: engineering, design, content and go-to-market.
Assuresoft / Mindless Labs
Senior React Native Engineer
09/2024 — 03/2026
Developed a wellness health mobile app focused on mindfulness and emotional wellbeing, available on both iOS and Android.
ScrumLaunch
Mid React Native Engineer
09/2022 — 03/2024
Worked on US-based client projects including Dabbl (rewards app) and Matchday (sports app for football fans).
Grão
Mid React Native Engineer
07/2020 — 07/2022
Core engineer on a Brazilian fintech super-app with 250K+ downloads. Implemented features across digital account, investments and transfers with bank-grade security and 80% test coverage.
Popstand
Mobile Developer Jr
10/2019 — 07/2020
Transitioned from QA to Development. Created E2E automation scripts with Detox, reducing manual regression testing time by 50%.
LEAD DELL
Mobile Developer Jr / Security Analyst
05/2018 — 07/2019
Contributed to internal corporate apps for Dell factory operations. Performed vulnerability assessments on mobile applications.
Get in touch
Open to remote contractor roles with US-based companies.