Arango (Leon) David

Tech: React Native, Expo 53, TypeScript, Zustand, React Query, ArcGIS Maps SDK, AsyncStorage, AES-256 Encryption, Axios, NativeWind, expo-location, expo-task-manager, WebView Highlights: ● ● ● ● ● ● ● ● Architected and delivered DFW’s next-generation field operations mobile app powering 100+ technicians and 200+ daily work orders. Delivered a full ArcGIS migration, implementing 4 custom WebView-based GIS components with real-time tech tracking, hex-based markers, zoom controls, and DFW coordinate system alignment. Built an encrypted, background-safe GPS breadcrumb system capturing technician location every 5 minutes using expo-task-manager + AES-256 secure storage. Designed a complete offline-first architecture (photo caching, comment persistence, retry queueing, network watcher) eliminating all field data loss. Integrated Hexagon EAM APIs for asset metadata, reducing equipment lookup time by 80% and improving first-time fix rate by 25%. Implemented real-time work order lifecycle events (onsite / pause / complete) with accurate wrench-time tracking for 200+ daily assignments. Delivered complex UI flows: draggable map pins, asset confirmation modals, bottom sheets, advanced permission system, and Figma-perfect component implementations. Built a smart auto-refresh engine using React Query with data-specific intervals and app-state awareness, reducing stale data by 98%. Impact: ● ● ● ● 150+ iPads deployed via ABM & Intune MDM 99.5% uptime with zero data loss Improved field tech productivity by 35% Authored 128+ production commits in 3 months

Tech: React Native, Expo, TypeScript, GraphQL, Apollo Client, Zustand, React Query, Reanimated, Bottom Sheet UI, Next.js 16, React 19, Tailwind v4, Stripe, Algolia, graphql-request, shadcn/ui Mobile App – Creator Analytics Dashboard ● Led end-to-end architecture of the Creator Analytics module, building metric cards, time-series charts, bottom sheets, and analytics hooks. ● Built the CommissionsBottomSheet (184 lines) with gradient-border UI, payout tracking, and interactive commission breakdowns. ● Developed custom hooks (usePayouts, useCommissionDetails, useCreatorAnalytics) increasing code reuse by 40%. ● Created TopCustomers, TopBrands, TopPosts, and SalesChart components using react-native-gifted-charts. ● Integrated Apollo GraphQL with optimized caching, reducing API calls by 35%. ● Achieved <200ms load times with zero critical bugs and full Jest test coverage. Web App – Brand Portal & Storefront Management ● Architected Next.js storefront dashboard for brands to manage product catalogs, commissions, shipping policies, and provider sync. ● ● ● ● ● Built StorefrontPageClient (451 lines) and 12+ modular sections (BankSetup, ProviderSync, CommissionRates, StorePolicies). Integrated Stripe Connect onboarding, reducing merchant setup time by 60%. Implemented Algolia-powered product search across 120+ SKUs with debounced queries. Built responsive Tailwind + shadcn layouts supporting mobile → 4K desktop. Created custom hooks (useStorefrontProducts, useMerchantSettings) with React Query and optimistic updates. Impact: ● ● ● 179 commits, 9,727 lines of production code (mobile + web) 45 features shipped in ~25 days 100% Figma design fidelity across both platforms

Antares Technologies March 2022 – June 2025 Tech Stack Utilized: React Native, TypeScript, Redux, Zustand, Xcode, Cocoapods, Firebase, Google APIs, Git, JIRA Led development of a cross-platform mobile voice recording and editing app (VoCap), ensuring robust performance and seamless user experience across iOS and Android. ● (S) Antares required a stable, high-quality mobile app to capture and process voice recordings with native-level performance on all major device architectures. ● (T) I led architecture design, tackled complex build and linking issues, and integrated advanced audio processing features to meet user demands. ● (A) Built modular React Native components, resolved Cocoapods and static library conflicts, optimized app runtime, and collaborated with product and QA teams to deliver feature updates on schedule. ● (R) Launched and maintained VoCap for 3 years, reduced crash rates by 50%, ensured smooth multi-architecture builds, and

Tech Stack Utilized: React.js, TypeScript, Redux, Jest, AWS Lambda, Git, JIRA ● ● ● Led front-end development initiatives, transforming complex designs into high-quality, responsive user interfaces using React.js. ○ (S) A pest control company required an in-house app to manage technician data and workflows effectively. ○ (T) I spearheaded the front-end design, creating a user-friendly interface while improving scalability. ○ (A) Designed modular React components, implemented Redux for state management, and ensured cross-browser compatibility. ○ (R) Delivered a responsive interface that reduced technician downtime by 25% and enhanced operational visibility. Optimized component performance to ensure seamless user experiences across multiple web platforms. ○ Used React.memo and useMemo for caching intensive computations, resulting in a 40% improvement in load times. Conducted regular code reviews and implemented best practices to maintain codebase integrity. ● ○ Standardized workflows via ESLint and Prettier for consistent code quality across teams. Collaborated closely with cross-functional teams to align technical solutions with business objectives. ○ Worked with stakeholders to prioritize features that drove 30% improvement in sales data visualization accuracy.

Airbnb | Remote Oct 2019 – Dec 2021 Tech Stack Utilized: React Native, Redux, React Native Elements, React Native Hermes, TypeScript, Jest, AWS S3, Git, JIRA ● ● ● ● ● Streamlined order and payment processes by integrating Redux and React Native Elements, enabling real-time live order updates. ○ (S) Users needed accurate real-time order tracking for improved booking reliability. ○ (T) Integrated Redux for consistent state management and React Native Elements for clean UI components. ○ (A) Developed dynamic order-tracking pages and APIs to handle real-time user updates. ○ (R) Achieved a 98% satisfaction rate for order tracking, increasing booking completion rates. Enhanced app performance using React Native Hermes and efficient Redux state management. ○ Improved app startup time by 60% on Android devices with Hermes and optimized reducer logic to minimize unnecessary state updates. Developed native modules for Apple Pay and Google Pay API integration. ○ Engineered Swift and Kotlin native modules to handle secure transactions, boosting checkout speeds by 25%. Implemented dynamic order fulfillment features using geolocation services. ○ Created geolocation-based provider recommendations and optimized routing APIs, improving delivery efficiency by 30%. Conducted unit testing with Jest and managed project tasks using JIRA. ○ Delivered 85% test coverage, identifying and resolving critical bugs pre-release.

Tech Stack Utilized: React Native, React Native Paper, Material Kit React Native, Express.js, MongoDB, Jest, Firebase ● ● ● ● Implemented React-Autocomplete for efficient data entry, improving user interaction on mobile platforms. ○ (S) Users struggled with manual data entry errors in financial forms. ○ (T) Implemented React-Autocomplete for smarter, predictive data entry. ○ (A) Built dynamic dropdown components integrated with Firebase for real-time data suggestions. ○ (R) Reduced form completion time by 40% and boosted user satisfaction scores. Developed RESTful API endpoints for user transaction history using Express.js and MongoDB. ○ Designed endpoints to handle large-scale transaction queries with minimal latency. Led UI/UX design efforts, utilizing React Native Paper and Material Kit React Native to enhance visual appeal and usability. ○ Delivered consistent Material Design layouts across iOS and Android platforms. Collaborated with back-end developers to ensure seamless data integration and functionality. ○ Coordinated front- and back-end API workflows, resulting in a 15% performance improvement for key data syncs.

React Native Developer Vogue Dec 2015 – Oct 2017 Tech Stack Utilized: React Native, Mapbox, Firebase, MongoDB, Fetch API ● ● Developed and maintained the Vogue Runway Fashion Shows mobile app using React Native, ensuring seamless cross-platform compatibility. ○ (S) Vogue needed an app to showcase live runway shows to a global audience. ○ (T) Built a cross-platform React Native app with offline mode for remote viewers. ○ (A) Integrated Mapbox for interactive location displays and Fetch API for content delivery. ○ (R) Achieved 1M+ downloads with a 4.8-star average rating on app stores. Contributed to the development of a map-based social network using React Native, Mapbox, Firebase, and MongoDB.

Tech: React Native, Expo 53, TypeScript, Zustand, React Query, ArcGIS Maps SDK, AsyncStorage, AES-256 Encryption, Axios, NativeWind, expo-location, expo-task-manager, WebView.

• Architected and delivered DFW’s next-generation field operations mobile app powering 100+ technicians and 200+ daily work orders
• Implemented WebView-based ArcGIS components with real-time tech tracking, hex-based markers, zoom controls, and coordinate alignment
• Built an encrypted, background-safe GPS breadcrumb system capturing technician location every 5 minutes using expo-task-manager and secure storage
• Designed an offline-first architecture (photo caching, comment persistence, retry queueing, network watcher) eliminating field data loss
• Integrated Hexagon EAM APIs reducing equipment lookup time by 80% and improving first-time fix rate by 25%
• Implemented real-time work order lifecycle events with accurate wrench-time tracking
• Built complex UI flows including draggable map pins, asset confirmation modals, bottom sheets, permissions, and Figma-perfect components
• Created a smart auto-refresh engine using React Query with app-state awareness, reducing stale data by 98%

Impact: 150+ iPads deployed via MDM, 99.5% uptime with zero data loss, 35% productivity improvement, 128+ production commits in 3 months

Tech: React Native, Expo, TypeScript, GraphQL, Apollo Client, Zustand, React Query, Reanimated, Bottom Sheet UI, Next.js 16, React 19, Tailwind v4, Stripe, Algolia, graphql-request, shadcn/ui.

Mobile App – Creator Analytics Dashboard:

• Built metric cards, time-series charts, bottom sheets, and analytics hooks
• Implemented CommissionsBottomSheet with gradient-border UI, payout tracking, and interactive commission breakdowns
• Created hooks (usePayouts, useCommissionDetails, useCreatorAnalytics) increasing code reuse by 40%
• Integrated Apollo GraphQL with optimized caching, reducing API calls by 35%
• Achieved <200ms load times with full Jest test coverage

Web App – Brand Portal & Storefront Management:

• Architected Next.js storefront dashboard for brands to manage catalogs, commissions, shipping policies, and provider sync
• Integrated Stripe Connect onboarding, reducing merchant setup time by 60%
• Implemented Algolia-powered product search across 120+ SKUs with debounced queries
• Built responsive Tailwind + shadcn layouts from mobile to 4K desktop with optimistic updates

Impact: 179 commits, 45 features shipped in ~25 days, and 100% Figma design fidelity across platforms

Led development of a cross-platform mobile voice recording and editing app (VoCap) across iOS and Android.

• Drove architecture design, resolved Cocoapods and static library conflicts, and optimized runtime performance
• Built modular React Native components and collaborated with product and QA for on-time releases
• Launched and maintained VoCap for 3 years, reduced crash rates by 50%, ensured smooth multi-architecture builds, and mentored junior developers

Tech: React.js, TypeScript, Redux, Jest, AWS Lambda, Git, JIRA.

• Led front-end development for an in-house technician app, transforming complex designs into responsive UIs
• Designed modular React components and implemented Redux for state management with cross-browser compatibility
• Used React.memo and useMemo to improve load times by ~40%
• Standardized workflows via ESLint and Prettier
• Partnered with stakeholders to prioritize features, improving sales data visualization accuracy by 30%

Tech: React Native, Redux, React Native Elements, Hermes, TypeScript, Jest, AWS S3, Git, JIRA.

• Streamlined order and payment processes with Redux and React Native Elements enabling real-time updates
• Improved Android startup time by 60% using Hermes and optimized reducer logic
• Built native modules for Apple Pay and Google Pay API integration, boosting checkout speeds by 25%
• Implemented geolocation-based provider recommendations and optimized routing APIs, improving delivery efficiency by 30%
• Achieved ~85% Jest test coverage and managed tasks in JIRA

Tech: React Native, React Native Paper, Material Kit React Native, Express.js, MongoDB, Jest, Firebase.

• Implemented React-Autocomplete to reduce data entry errors and speed up form completion by ~40%
• Built RESTful endpoints for transaction history with low-latency queries
• Led UI/UX efforts delivering consistent Material Design across iOS and Android
• Coordinated front- and back-end API workflows, yielding a 15% performance improvement for key data syncs

Tech: React Native, Mapbox, Firebase, MongoDB, Fetch API.

• Developed and maintained the Vogue Runway Fashion Shows app with cross-platform compatibility and offline mode
• Integrated Mapbox for interactive location displays and Fetch API for content delivery, achieving 1M+ downloads and a 4.8-star rating
• Contributed to a map-based social network enabling location-based user connections and event discovery
• Collaborated with design teams to translate visual concepts into pixel-perfect, functional applications

Tech: React Native, Redux, React Navigation, TypeScript.

• Built a reusable UI component library used across multiple features, reducing development time by 20%
• Integrated React Navigation and Redux for efficient state management and responsive navigation
• Improved chat performance by optimizing reducer logic and introducing lazy-loaded assets

Tech: Swift, Objective-C, Alamofire, Retrofit, RESTful APIs.

• Engineered biometric authentication systems and integrated RESTful API consumption using Alamofire and Retrofit
• Migrated codebase from Objective-C to Swift, reducing memory leaks by 30% and enhancing performance
• Delivered scalable mobile applications for iOS and Android, supporting 1M+ users with modular architecture