Chaitanya S

<p>Architected Spring Boot microservices ecosystem with RESTful and GraphQL APIs sustaining thousands of requests/second on peak retail endpoints; implemented API gateway patterns, service discovery, and distributed tracing across 15+ services.</p><p> Designed Java-based event-driven architecture using Kafka for asynchronous communication between inventory, pricing, and fulfillment microservices, reducing inter-service coupling and improving system resilience by 30%.</p><p> Built Spring Security OAuth2/JWT authentication and authorization layers enforcing RBAC for 400K+ associate accounts across internal and public-facing APIs with zero reported breaches.</p><p> Engineered high-throughput PostgreSQL + Redis caching strategies (write-through, cache-aside) reducing database load by 55% and achieving sub-50ms P99 latency on critical product search endpoints.</p><p> Integrated AI-powered demand forecasting into Spring Boot inventory microservices using OpenAI API and LangChain4j; automated stock replenishment recommendations reduced overstock incidents by 28% across 4,700+ store locations.</p><p> Pioneered vibe coding workflows across a 20-member engineering team using Cursor AI and GitHub Copilot for Spring Boot service scaffolding, boilerplate generation, and test authoring, accelerating feature delivery velocity by 35% and reducing code-review turnaround by 40%.</p><p> Built AI-assisted API contract validation tooling (Claude API + custom Java linter) that auto-detected schema drift between producer and consumer microservices pre-deployment, eliminating 60% of breaking-change production incidents.</p><p> Developed Kotlin Android UI layers with programmatic views and Bluetooth/BLE integrations (barcode scanners, POS peripherals, payment terminals) exposed to Java backend via shared DTOs and strongly-typed API contracts.</p><p> Architected cross-platform React + React Native features sharing business logic, design tokens, and REST/GraphQL API contracts, serving 400K+ associates and millions of public users globally; built MFE modules via Module Federation with lazy-loaded routes and independent CI deployment.</p><p> Achieved 38% faster app launch and 42% lower screen-load latency via Hermes engine, code-splitting, and API response compression; enforced 95% code consistency with shared ESLint/Prettier/TS configs in Nx monorepo across 4 squads.</p>

<p>Built a high-performance Java/Spring Boot data-fetching layer with request deduplication, adaptive retry, and circuit-breaking patterns, saving $350K/year in infrastructure costs and improving backend throughput by 35%.</p><p> Designed GraphQL schema federation across 10+ Java microservices, enabling unified querying for Instagram’s feed, stories, reels, and commerce surfaces while maintaining strict data ownership boundaries.</p><p> Implemented offline-first sync architecture with a Java background queue and conflict-resolution engine, boosting engagement in low-bandwidth markets by 24% and reducing transaction drop-offs by 18%.</p><p> Engineered Spring Boot checkout microservices with idempotent payment processing and distributed transaction management; mobile checkout enhancements drove $12M+ incremental annual revenue (+16% conversion rate).</p><p> Adopted feature-based DDD modular architecture across Java services, cutting cross-team merge conflicts by 40% and enabling 12 squads to deploy independently without service-level coordination.</p><p> Deployed Sentry + distributed tracing (Zipkin/Jaeger) across Java microservices and mobile clients; improved crash-free sessions from 97.1% to 99.6% through systematic root-cause analysis and hotfix automation.</p><p> Led Mobile COE device farm initiative with automated Espresso/JUnit regression suites on real Android/iOS devices; reduced QA cycle time by 50% and hardware costs significantly across a 25-engineer organization.</p><p> Delivered React web + React Native feature parity for millions of monthly Instagram users, sharing GraphQL queries, DTOs, and validation logic across platforms with a single source of truth.</p><p> Reduced cold start by 46% and JS bundle size by 31% via Hermes, RAM bundle splitting, and native module bridging; implemented CI/CD with automated performance regression checks reducing production incidents by 36% YoY.</p><p> Engineered Redux + Redux-Saga state management with typed APIs and analytic event schemas for React Native; built adaptive UI components with RTK Query caching delivering consistent UX across Android and iOS at scale.</p>

<p>Architected Spring Boot RESTful APIs (Retrofit + OkHttp, Axios) with OAuth2/JWT biometric authentication, role-based authorization, and structured exception handling supporting thousands of concurrent internal users.</p><p> Built Java backend microservices with Repository Pattern and Clean Architecture principles; integrated PostgreSQL with Hibernate ORM and Redis caching, reducing average query time by 35% on high-traffic endpoints.</p><p> Implemented Firebase FCM push notification pipeline via Java Spring Boot scheduler service, delivering targeted alerts to 50K+ devices with 99.5% delivery success rate and sub-second latency.</p><p> Developed WebSocket-based real-time update service in Spring Boot for live status feeds on field technician dashboards, replacing polling and reducing server load by 45%.</p><p> Authored comprehensive JUnit and Mockito test suites for service and repository layers; integrated Espresso and Detox for end-to-end mobile test automation, achieving 80%+ code coverage across all critical modules.</p><p> Configured GitHub Actions + Fastlane CI/CD pipelines for automated Play Store and App Store deployments with semantic versioning, build signing, and staged rollouts reducing deployment errors by 70%.</p><p> Performed JMeter load testing and ProGuard/R8 optimization on Android SDK (Kotlin/Java) builds; applied MVVM and Repository Patterns reducing memory overhead by 22% on low-end Android devices.</p><p> Built cross-platform mobile applications in React Native (TypeScript/ES6+) following Clean Architecture and MVVM; delivered feature parity on Android and iOS for thousands of internal field operations users.</p><p> Integrated deep linking, WebSockets, and biometric auth in React Native with custom native modules bridging Java/Kotlin code, enabling seamless real-time notifications and secure single-tap login flows.</p><p> Optimized FlatList rendering and Hermes engine configuration in React Native, achieving 25% faster startup and 20% crash reduction; enforced component reusability via Storybook-driven design system.</p>