Matheus – React, React Native, JavaScript

An independent product and software-delivery portfolio spanning production AI systems, SaaS tools and published iOS/Android applications. Recent products include Puff Zero, SnapSweep and Nutri AI, alongside analytics dashboards and app-store operations tooling.

• Owned product architecture, implementation, API integrations, testing, releases and operational fixes across web and mobile products.
• Built Python/FastAPI and TypeScript services with LLM integrations, retrieval and production failure handling.
• Delivered mobile features including subscriptions, analytics and app-store release workflows.
• Built SoleOS analytics integrations for product, advertising and app-store reporting, plus Manifest tooling for localized store copy and App Store Connect publishing workflows.
• Used AI-assisted development with human review, automated tests and explicit delivery checks.

An AI-assisted platform for business audience research and marketing strategy, combining a customer-facing web application with model-provider integrations and an agent that could work with application data.

• Owned frontend and backend application architecture and implementation.
• Built an AI agent that interacted with the application database and integrated OpenAI, Anthropic and other model providers.
• Created reusable interface components to keep product development consistent across the application.
• Diagnosed and resolved application issues using Sentry and local debugging.
• Wrote unit, integration and end-to-end tests for key application flows.

A real-estate platform helping brokers manage relationships with clients and leads. The product combined customer-facing workflows with property information from multiple MLS data sources.

• Developed production features across the React frontend and Node.js backend.
• Designed caching to support concurrent requests and reduce repeated data access.
• Improved existing frontend workflows and reusable interface behaviour.
• Integrated multiple MLS data sources into the platform's property workflows.
• Worked with PostgreSQL, Redis, MongoDB, AWS and RabbitMQ across application data and background processing.

A fintech proof of concept and MVP that used banking transaction data to understand spending patterns and suggest relevant rewards and promotions.

• Delivered the proof of concept and MVP as the sole developer.
• Designed and implemented the frontend and backend architecture with Next.js, React, Node.js and Supabase.
• Integrated banking providers to retrieve transaction data and built webhook endpoints for incoming events.
• Connected transaction-driven workflows to the application's rewards and recommendation experience.

A children's learning product combining English-language activities with biblical stories and values, supported by a mobile application and administration tools.

• Built core application features and administration workflows with React, Next.js and React Native.
• Created an AI-assisted content-generation system for learning materials.
• Implemented usage tracking in the administration system.
• Built parallel processing workflows and microservices to coordinate AI-assisted cartoon and video content creation.

A multiplayer trivia product with real-time player interactions, player-versus-player battles and multiple game modes.

• Set the product's technical direction and engineering roadmap as CTO.
• Led collaboration across software development, game design and quality assurance.
• Worked on service architecture and WebSocket-based real-time gameplay.
• Established continuous integration and delivery workflows for product updates.
• Integrated monitoring and analytics to support production operation and technical decisions.

A web commerce experience for product discovery, purchasing and scheduled deliveries, with integrations for payment processing and supporting backend services.

• Designed frontend and backend application architecture using Next.js, React and Node.js.
• Built responsive shopping interfaces and a reusable component library.
• Integrated payment workflows with PayPal and Stripe.
• Diagnosed production issues using Sentry, Elasticsearch and Kibana.
• Wrote Jest tests and worked with cloud delivery and CDN integrations.

A commerce platform connecting customers with brands through mobile and web shopping experiences, supported by ordering, fulfilment and delivery workflows.

• Designed and implemented APIs and background workers for commerce workflows.
• Led product delivery from requirements and partner dependencies through implementation, testing and production checks.
• Worked across React Native, Node.js, MongoDB, Firebase and Kubernetes.
• Added telemetry, correlated logging, metrics, alarms and dashboards to support operation and debugging.
• Supported code reviews, CI/CD and unit, integration, end-to-end and load testing as part of engineering delivery.

A wellness and beauty marketplace for discovering services, booking appointments and making payments through web and mobile applications, with wallet, benefits and cashback workflows.

• Built web and React Native experiences for service discovery, search and location-based browsing.
• Developed APIs and administration tools with Ruby on Rails and Elixir/Phoenix.
• Implemented backend and administration workflows with React, SQL data and Redis.
• Worked with AWS and Heroku deployment and cloud integrations.
• Automated marketing-experiment business logic, including A/B and multivariate testing.

A B2B SaaS platform enabling businesses to create white-label NFT stores and marketplaces.

• Led technical delivery and coordinated the development team.
• Worked on smart-contract integration and related application workflows.
• Improved loading behaviour for high-resolution NFT media.
• Worked with Vue.js, Ethereum, smart contracts and IPFS.

A Brazilian gas-delivery commerce product that let customers order cylinders immediately, schedule purchases and manage repeat ordering through mobile and web workflows.

• Built commerce and administration features across Ruby on Rails, Node.js, React and React Native.
• Owned end-to-end cancel, return and exchange workflows within the commerce platform.
• Integrated third-party systems supporting transaction, reporting and charting workflows.
• Worked with application data, background processing and cloud services across the product.