Senior Frontend Engineer
with 10+ years of experience
I'm Renan Martins, a Senior Frontend Engineer based in Ceara, Brazil, working remotely with teams worldwide. I specialize in building high-performance web applications using React, TypeScript, and Next.js, with a track record of delivering measurable business results.
Currently at Planetary, I lead frontend development for large-scale digital products serving clients like California Pizza Kitchen, Din Tai Fung, and The Wall Street Journal. My focus is on performance optimization, accessibility, and architecting CMS-driven multilingual websites.
Throughout my career across fintech, travel tech, and food e-commerce, I've consistently delivered impactful results: reducing page load times by up to 60%, increasing conversion rates by 30%, and achieving 90+ Lighthouse scores across hundreds of pages.
Notable Achievements
60%
Page Load Reduction
From 10s to 4s on large B2C platform
30%
Conversion Increase
Through SSR migration and optimization
90+
Lighthouse Score
Across 100+ pages with a11y best practices
35%
Infrastructure Cost Reduction
Via ISR caching and smart revalidation
Values & Approach
The principles that guide my work and collaboration style
Performance First
Every millisecond matters. I focus on optimizing page load times and Core Web Vitals to deliver exceptional user experiences.
Business Impact
Technical excellence should translate to business results. I measure success by conversion rates, user engagement, and ROI.
Clean Architecture
Maintainable code is sustainable code. I build scalable systems with clear patterns and comprehensive documentation.
Continuous Learning
The web evolves rapidly. I stay current with best practices while sharing knowledge through mentoring and code reviews.
Experience
10+ years building software across fintech, travel tech, and food e-commerce
Senior Frontend Engineer
Planetary
04/2022 - Present
New York, NY - USA (Remote)
Digital agency building high-scale digital products for brands such as Google, Amazon, and Univision.
- Reduced page load speed by 25% (from ~4.4s to ~3.3s) by optimizing UI and page architecture in a high-traffic Next.js app serving 400k+ monthly users
- Cut infrastructure costs by 35% and boosted Lighthouse score by 30+ points (from 60 to 90+) with ISR caching and webhook-based revalidation
- Increased catering revenue by 10% by redesigning restaurant e-commerce funnel with smart location-based features
- Delivered 100% content integrity in Sanity CMS multilingual data migration using GROQ queries and TypeScript scripts
Senior Frontend Engineer
Agility Creative - Project: MINE
12/2021 - 04/2022
Fortaleza, CE - Brazil (Remote)
B2B startup offering high-quality software development solutions.
- Increased weekly organic traffic by 22% and achieved 90+ Lighthouse score through SEO and performance optimization
- Reduced homepage load time by 20% with responsive images, lazy loading, and component refactoring
- Drove 10,000 user signups and ~10% conversion (~990 orders) with AI-powered style-discovery feature
- Improved design system consistency with scalable React + TypeScript + Tailwind CSS + Storybook components
Senior Frontend Engineer
Agility Creative - Project: RD Station Marketing
07/2021 - 12/2021
Fortaleza, CE - Brazil (Remote)
Marketing automation SaaS platform.
- Increased plan conversion rate by 7% and upsell rate by 12% with high-impact pricing page experiment
- Boosted monthly engagement by 66% (150 to 250 actions) with React + Ruby onboarding flow
- Deployed 30+ product growth experiments focused on retention, engagement, and conversion
Frontend Engineer
Agility Creative - Project: DeOnibus
03/2018 - 07/2021
Fortaleza, CE - Brazil (Remote)
Travel tech e-commerce platform for bus tickets.
- Reduced page load time by 60% (from 10s to 4s) migrating legacy frontend to React with SSR, lazy loading, and Redis caching
- Recovered ~5% of lost orders (~500) with Node.js REST API and TypeScript bot for automatic payment retries
- Increased e-commerce conversion rate by 30% (from ~2% to ~2.6%) on platform with millions of annual orders
- Decreased fraud attempts by 14% (~2,800/year) optimizing payment validation and Adyen integration
Education
Post-Graduation in Competitive Intelligence and Innovation in Marketing
Estacio de Sa University, Brazil
2018
Bachelor's Degree in Information Systems
Estacio de Sa University, Brazil
2016
Languages
Interested in working together?
I'm currently open to new opportunities including full-time remote positions, contract work, and consulting engagements.
Let's Connect