William Fernandes

Senior Full Stack Developer

Summary

Full-stack developer with 10+ years building high-performance web and mobile apps using Laravel, React.js, and React Native. Shipped complex systems like ticketing platforms, social media network, and hardware-limited apps, delivering scalable, offline-first, and real-time solutions for Web, Android, and iOS.

Experienced working with teams and clients in Brazil and the United States, adapting to diverse technical and business environments.

Experience

MeetArtLink

Sep 2021 - Dec 2024

Senior React Native Developer

Los Angeles, California, United States

Architected and developed a full social media and e-learning mobile platform for artists and art enthusiasts using React Native and Firebase (Firestore, Cloud Functions, Cloud Storage).
Built a real-time group chat feature with invites, multimedia and low latency live streaming via CDN.
Built a post feed with support for text, image, and video posts. Implemented media upload to a global CDN with progress tracking, resumable uploads and compression reducing the storage and bandwidth costs up to 80%.
Designed and integrated a AI assistant by fine-tuning a LLM to support students with homework tasks without providing direct answers. This boosted the teacher-student support capacity by 5x.

Wave Tickets

Jun 2023 - Aug 2024

Senior Full Stack Developer

São Paulo, São Paulo, Brazil

Rebuilt the event producer dashboard to significantly improve performance, usability, and user experience.
Achieved a 10x improvement in reports page load time using Laravel, applying smart caching with Redis, optimizing MySQL indexes, rewriting slow queries and using eager loading to minimize N+1 issues.
Developed the front-end with Inertia.js and React.js to improve in more than 50% the page loading and navigation. Used Radix UI primitives to deliver a more accessible and polished interface, making it easier to manage reports and key platform features.

UP Tickets

Aug 2017 - May 2023

Full Stack & Mobile Developer

Ribeirão Preto, São Paulo, Brazil

Led the design, architecture and development of multiple platforms, including a web ticketing system, event producer dashboard, mobile sales apps, promoter app, and real-time validation app. Worked primarily with Laravel, React.js and React Native (Android and iOS), and deployed and scaled most services on AWS.
Played a key role in transforming the company from a small startup with a basic web service into a robust, scalable, multi-app ecosystem supporting high-demand, nationwide events and driving revenue growth from R$1M to over R$40M per year.
Integrated web and mobile apps with major Brazilian payment providers PagSeguro, Cielo, Safra, and Getnet. expanding the company’s ticket distribution channels and significantly increasing sales.
Built most apps with React Native optimized for low-end Android PoS devices (1 GB RAM, dual-core CPU), including a custom native Java modules to maximize performance between the JavaScript and native threads, ensuring stability and low memory usage during high-volume data operations, such as real-time ticket validation during event openings.
Developed the "UP Tickets Bar" app using React Native as an offline-first, real-time sales solution for Android PoS devices used inside events. Enabled staff to sell consumable items directly on the event floor using mobile terminals, increasing transaction volume and revenue through on-site, high-speed processing, even without constant internet access.
Engineered batch processing and queue system in Laravel to import and process millions of third-party tickets (e.g., from Sympla, Ticketmaster) without overloading the servers.
Developed a mobile-first promoter app (PWA) that allowed external promoters to sell tickets from any device without installing apps, greatly expanding the company’s distribution network and increasing sales.

ProGuard

Jan 2017 - Jul 2017

Full Stack Developer

Rio de Janeiro, Rio de Janeiro, Brazil

Developed a real-time web application with Laravel for online game owners view and action on anti-cheat data. At the time the system was filtering and handling over 200.000 events per day.
Implemented behavior-based heuristics to detect suspicious patterns, cutting enforcement response time by 50% and enabling faster bans, cooldowns, and account restrictions to mitigate cheating at scale.

Point da Recarga

Jan 2015 - Dec 2016

Full Stack Developer

Alagoinhas, Bahia, Brazil

Built a cloud-based, multi-tenant internal system using Laravel and JavaScript to replace a legacy desktop solution across multiple company branches in different cities, reducing operational costs by over R$5,000 per month.
Migrated all core features, added new custom functionalities including a new parts supply and inventory management system, reducing inventory errors by 40% and speeding up restocking operations by 100%, significantly boosting operational efficiency.

FT Hosting

Jun 2013 - Aug 2014

Front-End Developer

Ribeirão Preto, São Paulo, Brazil

Modernized the company’s front-end using jQuery and SASS, implementing a consistent design system with cross-browser compatibility and visual consistency across the platform.
Delivered a fully mobile-first, responsive layout, an important achievement at a time when mobile optimization was just becoming essential.
Gained foundational experience in modern front-end practices, responsive design, and cross-browser compatibility.

Education

Universidade Estadual da Bahia (UNEB)

Bachelor of Systems Information

2015 - 2019

Achievements

Top 25 Finalist – IBM Behind the Code (2019)

Aug 2019

Selected among 25,000+ developers in a 42-day national challenge focused on solving real business problems using disruptive technologies including AI, IoT, Blockchain, Kubernetes, and IBM Cloud solutions. Ranked in the top 0.06% of participants.

Skills

Languages

Portuguese - Native

English - Advanced