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willian User

@willianuser

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Fullstack engineer specializing in Node.js, React, TypeScript, AWS and AI-powered solutions.

Brazil

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What I'm looking for

I’m seeking a remote engineering role where I can build scalable, high-performance web platforms, contribute to architecture and infrastructure, and apply AI features to deliver measurable user and business impact.

I am a Fullstack Software Engineer with seven years of experience building and scaling web applications from scratch for fintech and security platforms, focusing on performance and maintainability.

I have led architecture and infrastructure decisions, migrated infrastructures to AWS with Terraform, implemented CI/CD with GitHub Actions, and built large-scale data pipelines for high-volume credit data processing.

On the frontend I’ve driven design systems, micro-frontend migrations, and performance improvements using React, TypeScript, Redux, and testing tools, increasing engagement and reducing load times across products.

I mentor peers and interns, develop AI-powered tools (RAG and fine-tuning), and prioritize clean, documented code and scalable solutions that accelerate user adoption and business outcomes.

Experience

Work history, roles, and key accomplishments

Current

Full Stack Engineer

Current

Hansa

Apr 2024 - Present (1 year 6 months)

Participated in early system design and built the fintech platform from scratch, migrated infrastructure from DigitalOcean to AWS with Terraform, and developed AI-powered tools and a large-scale data pipeline to process credit data, driving first 400 active users within 3 months.

TypeScript Remix AWS ECS RDS S3 Terraform GitHub Actions JavaScript Streams AWS Glue

Frontend Engineer

OpenVPN Inc

May 2022 - Apr 2024 (1 year 11 months)

Built the frontend for OpenVPN Cloud, improved UI performance and load times (25% and 20% respectively), led creation of a company-wide design system and expanded the component library to increase reuse and reliability.

React TypeScript Redux Redux Saga Storybook Jest Performance Optimization Design Systems

Frontend Engineer

Traders Club

Jul 2021 - May 2022 (10 months)

Rebuilt the frontend with Next.js and TypeScript, created a personalized financial dashboard that increased engagement by 25%, and migrated the app to a micro-frontend architecture to improve performance and conversion.

Next.js TypeScript React React Query Zustand styled components A B Testing Performance Monitoring Jest

Fullstack Software Engineer

Phi

Jul 2020 - Jul 2021 (1 year)

Developed personalized payment solutions and microservices for fintech clients, built a real-time credit analysis app using WebSocket APIs, and implemented asynchronous microservice communication with NestJS and RabbitMQ.

NestJS React Redux Saga TypeScript RabbitMQ MySQL MongoDB WebSockets

Frontend Developer

Allimsa

Jan 2020 - Jul 2020 (6 months)

Contributed to core modules for a chemical laboratory management platform, implemented multitenant white-label architecture and complex data visualizations, delivering solutions adopted by major clients.

React TypeScript GraphQL Data Visualization Performance Optimization Testing

Full Stack Developer

Simplo7

Aug 2018 - Jan 2020 (1 year 5 months)

Implemented customer-data migration systems and maintained internal tools for an e-commerce platform, optimized integrations with payment gateways and logistics to improve checkout and delivery experiences.

React Data Migration Integration API Development Performance Optimization