Alex Rivera

The Challenge

Our team was struggling with project management tools that felt clunky and slow. We needed something lightweight, fast, and actually enjoyable to use. Leadership gave me the green light to build our own internal tool that could eventually become a product.

My Role & Approach

I architected and built the entire application from the ground up. Started with user research (talked to 20+ team members about their pain points), then designed a clean, intuitive UI that prioritized speed and simplicity.

• Built drag-and-drop Kanban boards using React Beautiful DnD with smooth animations
• Implemented real-time updates with Socket.io so team members see changes instantly
• Created a notification system that actually respects your time (no spam!)
• Designed a MongoDB schema that could scale from 10 users to 10,000
• Added team chat functionality so context lives with the work
• Built comprehensive test suite with 85% code coverage

Technical Highlights

• Frontend: React with hooks, Context API for state management, TypeScript for type safety
• Backend: Node.js/Express REST API with JWT authentication
• Real-time: Socket.io for live updates, Redis for pub/sub messaging
• Database: MongoDB with Mongoose, optimized indexes for fast queries
• Testing: Jest for unit tests, React Testing Library, Cypress for E2E

Results & Impact

The app launched internally and within 3 months, 100% of the company adopted it (replacing three other tools). Productivity metrics showed 30% faster project completion times. We eventually spun it into a SaaS product that's now used by 50+ companies. This project earned me my first promotion to mid-level developer.

The Challenge

A mid-sized retail client needed to move online FAST (thanks, pandemic). They had a budget, a tight deadline, and zero technical infrastructure. They needed everything: product catalog, payment processing, inventory management, shipping integration, and it all had to be mobile-first.

My Role & Approach

I led a team of 3 developers and was responsible for architecture decisions, code reviews, and building the core functionality. We chose Next.js for its SEO benefits and server-side rendering capabilities.

• Architected full-stack e-commerce solution using Next.js 12 with App Router
• Integrated Stripe for payments (including Apple Pay and Google Pay)
• Built admin dashboard for inventory management and order tracking
• Implemented product search with Algolia for lightning-fast results
• Created responsive design that works flawlessly on mobile (where 70% of traffic comes from)
• Set up Vercel deployment with automatic preview deployments for every PR

Technical Stack

• Frontend: Next.js 12, TypeScript, Tailwind CSS, Framer Motion
• Backend: Next.js API routes, PostgreSQL with Prisma ORM
• Payments: Stripe integration with webhooks for order confirmation
• Search: Algolia for product search and filtering
• Storage: AWS S3 for product images with CloudFront CDN
• Monitoring: Sentry for error tracking, Vercel Analytics

Results & Impact

Launched in 7 months (1 month ahead of schedule). First month revenue: $250K. By month 6: $1.2M. Average page load time: under 2 seconds. Mobile conversion rate: 3.8% (industry average is 2.1%). This project established me as the go-to person for complex architecture decisions.

The Challenge

Our analytics team was drowning in spreadsheets. They needed a way to visualize customer data, track KPIs, and generate reports without manually creating 50 Excel charts every week. The twist? Data updates in real-time from multiple sources, and executives want to access it from their phones.

My Role & Approach

I handled everything solo—from requirements gathering to deployment. Learned D3.js specifically for this project because Chart.js wasn't flexible enough for our complex visualization needs.

• Built interactive dashboards with 15+ chart types (line, bar, pie, heatmaps, sankey diagrams)
• Implemented real-time data streaming using Server-Sent Events
• Created drag-and-drop dashboard builder so users can customize their views
• Added CSV/Excel export functionality with formatting options
• Designed responsive layouts that work beautifully on tablets and phones
• Built query builder so non-technical users can filter and segment data

Technical Implementation

• Frontend: React 18 with hooks, D3.js v7 for charts, React-Grid-Layout
• Backend: Node.js/Express, PostgreSQL with time-series optimizations
• Real-time: Server-Sent Events for live data updates
• Performance: React Query for caching, virtualized lists for big datasets
• Export: ExcelJS for Excel generation, Papa Parse for CSV

Results & Impact

Reduced report generation time from 5 hours/week to 5 minutes. Analytics team can now respond to executive questions in real-time instead of "let me get back to you tomorrow." Ad-hoc report requests dropped by 80%. The CEO uses it daily. This earned me the "Developer of the Quarter" award.

The Challenge

Company wanted to build an internal team-building game that could be played during remote meetings. Requirements: run in browser (no downloads), support 20+ players simultaneously, low latency for real-time gameplay, and it actually had to be fun.

My Role & Approach

Led technical development, focusing on the networking layer and game state synchronization. This was my first deep dive into game development, and I learned SO much about frame rates, interpolation, and client-side prediction.

• Built game engine using HTML5 Canvas API with 60 FPS performance
• Implemented authoritative server architecture to prevent cheating
• Created matchmaking system with ELO-based skill rating
• Used WebRTC for peer-to-peer voice chat during gameplay
• Built leaderboard system with Firebase Realtime Database
• Added replay functionality so players can watch their best moments

Technical Stack

• Game Engine: Vanilla JavaScript, Canvas API, custom physics engine
• Networking: Socket.io for game state, WebRTC for voice
• Backend: Node.js with tick-based game loop running at 60 TPS
• Database: Firebase for user profiles, matches, leaderboards
• Hosting: DigitalOcean droplets in multiple regions for low latency

Results & Impact

Launched at company all-hands with 150 people playing simultaneously (servers held!). Became the most-used internal tool with 300+ daily active users. Reduced "Zoom fatigue" by giving teams something fun to do together. Got featured in company blog, and several employees asked if we could open-source it (still considering).

The Challenge

Marketing team was spending 15+ hours per week writing product descriptions, social media posts, and email campaigns. They needed a tool that could generate high-quality content quickly while maintaining brand voice. Budget constraint: keep API costs under $500/month.

My Role & Approach

Built a smart caching system to minimize OpenAI API calls (because those tokens add up fast!). Created a template library so common content types could be generated consistently.

• Integrated OpenAI GPT-4 API with custom prompt engineering for brand consistency
• Built template library with 20+ content types (product descriptions, tweets, emails, blog outlines)
• Implemented Redis caching to avoid regenerating similar content
• Created tone/style controls so content matches brand guidelines
• Added content history and favorites for reusing successful outputs
• Built usage analytics to track API costs and optimize prompts

Technical Implementation

• Frontend: TypeScript, React with TanStack Query, Monaco Editor for content editing
• Backend: Node.js/Express, OpenAI API with streaming responses
• Caching: Redis for content caching, 7-day TTL, semantic similarity matching
• Queue: Bull queue for background generation jobs
• Monitoring: Custom dashboard tracking token usage, costs, generation quality

Results & Impact

Reduced content creation time from 15 hours/week to 3 hours/week. Marketing team can now test 10 different product descriptions in the time it used to take to write one. Increased content output by 300% without hiring additional staff. Tool expanded to sales team for proposal writing.

The Challenge

Company wanted to test a social media concept targeting Gen Z users. Had to be mobile-first, feel native but work on web, support photo sharing with filters, and handle real-time likes/comments. Oh, and we needed an MVP in 3 months.

My Role & Approach

Architected as a Progressive Web App (PWA) so users get app-like experience without downloads. Built custom image processing pipeline because existing solutions were too slow or expensive.

• Built React PWA with offline support and install prompts
• Implemented camera access and real-time image filters using Canvas API
• Created infinite scroll feed with lazy loading and image optimization
• Built GraphQL API for flexible data fetching and real-time subscriptions
• Integrated AWS S3 for image storage with CloudFront CDN for fast delivery
• Added push notifications for likes, comments, follows

Technical Stack

• Frontend: React with Vite, PWA with Workbox service worker
• API: GraphQL with Apollo Server, subscriptions for real-time updates
• Backend: Node.js, PostgreSQL, Redis for caching and pub/sub
• Image Processing: Sharp for server-side optimization, Canvas for client filters
• Storage: AWS S3 + CloudFront, automatic WebP conversion
• Auth: JWT with refresh tokens, OAuth for social login

Results & Impact

Beta launched to 500 users, grew to 5,000 in 2 months through word-of-mouth. 70% of users visit daily. Average session time: 12 minutes (higher than Instagram for our demographic!). App installs: 2,800 despite being web-based. Company now considering full product launch.