Joel Maria
I'm Specialized in
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Front-End & Mobile UI/UX Design
JavaScript
React
Redux
GraphQL
Next.js
React Native
Gatsby
HTML
Laravel
Python
Angular
Back-End Development
Node.js
Prisma
Django
Firebase
Docker
Kubernetes
AWS
Google Cloud
Supabase
01. About me
Senior Staff Engineer with over 16 years of experience building high-performance web and mobile applications for FinTech, SaaS, and enterprise platforms. Specializes in React, React Native, Node.js, Python, and cloud technologies (AWS, GCP, Firebase), designing scalable systems, AI-native architectures, and robust frontend experiences. Enjoys leading teams, optimizing platforms for millions of users, and integrating AI-powered, automation-driven capabilities to deliver intelligent, production-grade software.
02. Interests and Hobbies
I enjoy exploring emerging technologies, contributing to open source projects, and staying active through running, cycling, and hiking. I also love traveling, discovering new cultures, and expressing creativity through photography, music, and design
03. Framework Preferences
I primarily work with React and React Native for building responsive web and mobile applications. On the backend, I prefer Node.js with Express.js or Fastify.js, and Python with Django for scalable and robust server-side solutions. I also have experience with GraphQL, Firebase, and cloud-native frameworks on AWS and Google Cloud.
Employment
Senior Software Engineer, AI-Scale Platform Architecture
Upwork (Contract) | Boston, MA
Led architecture for high-scale creator and gaming platforms serving 50M+ global consumers, designing distributed, event-driven systems across Node.js (TypeScript) and Python (FastAPI, asyncio). Architected and scaled horizontally distributed microservices and Kafka-based streaming pipelines powering real-time telemetry and mission-critical financial transactions with strong consistency guarantees and resilience under burst traffic conditions. Re-architected GraphQL APIs and data access layers, achieving 200% performance gains through resolver optimization, request batching, caching strategies, and query cost governance. Engineered non-blocking I/O, clustering, and async concurrency controls to maximize throughput while sustaining low-latency SLAs across high-traffic endpoints. Designed streaming-first telemetry contracts and enrichment pipelines enabling AI/ML-ready workloads for behavioral analytics, fraud detection, and adaptive monetization. Improved platform reliability and cost efficiency through structured observability (metrics, tracing, logs) and increased mobile performance by 35% via deep React Native Hermes optimization.
Lead Engineer – AI Voice & Distributed Banking Systems
U.S. Bank | Boston, MA
Co-defined architecture for AI voice assistant powered by Node.js, Python, and TensorFlow inference services. Designed secure integration layer between mobile clients, ML inference services, and core banking systems. Implemented streaming API interactions for low-latency inference workflows. Designed scalable microservice communication model across distributed domains. Reduced application footprint by 20% through modular build strategies and dependency rationalization. Led 22 engineers building enterprise UI platform with 80%+ test coverage.
Fullstack Engineer – High-Scale Distributed SaaS Platform
Grax | Boston, MA
Architected a Kubernetes-native Node.js platform handling 100M+ monthly API requests, enabling automated horizontal scaling and high-availability multi-tenant SaaS workloads. Led migration from REST polling to WebSocket streaming, reducing end-to-end latency by 50% and doubling real-time concurrency capacity. Optimized cloud infrastructure through container rightsizing, caching strategies, and batch processing, reducing operational costs by $67K/month. Designed event-driven data pipelines with BigQuery and implemented distributed OAuth2/JWT identity across services, establishing scalable retrieval and indexing patterns later leveraged for semantic and vector-based search architectures.
Senior Software Engineer – Distributed Identity & Microservices
Costar | Boston, MA
Designed OAuth2 + JWT authentication systems supporting 5M+ daily logins. Built Backend-for-Frontend layer consolidating multiple domain services. Developed 60+ REST services with resilience patterns and observability hooks. Improved fault isolation and error handling across distributed services.
Fraud Detection Engineer – Streaming & Real-Time Systems
Fidelity Investment | Boston, MA
Built real-time fraud detection services using Kafka, Redis, Django. Designed event-driven anomaly detection pipelines. Integrated external intelligence APIs for automated risk verification. Delivered real-time visualization dashboards for transaction monitoring.
Full-stack React.js Developer
Verizon Wireless Solutions | Boston, MA
Built RESTful microservices in Node.js and MongoDB to manage nationwide cable infrastructure and equipment mapping. Developed cloud management modules for compute, storage, and network automation on Verizon's IaaS platform. Enhanced platform scalability and data synchronization across distributed systems.
Senior Mobile Engineer (Contract Role)
Bank of America | Boston, MA
Developed native mobile modules in Java and Objective-C, integrating secure biometrics and OCR scanning into a hybrid Cordova/PhoneGap app used by 46M+ customers. Modernized legacy banking workflows by introducing Backbone.js and AngularJS architectures, improving UI performance for millions of users. Refactored large-scale Java monoliths into RESTful web services handling 1.6B+ annual transactions.
CSS3 Lead Developer
TD Ameritrade | Boston, MA
Built a SASS/Compass framework automating sprite generation and vendor prefixing, cutting load times by 40%. Applied OOCSS and Bootstrap/LESS for modular, maintainable, and responsive UI architecture. Delivered a hybrid Cordova/HTML5 app deployed on Android and iOS.
Freelance Back-End and Front-End Developer
Elance | Lawrence, MA | Remote
Built full-stack PHP/CodeIgniter systems including RESTful APIs, data-feed processors, and web crawlers using MySQL/PostgreSQL. Delivered custom enterprise modules such as multi-currency invoicing and image-processing pipelines. Converted legacy assets into high-performance HTML/CSS interfaces using jQuery and AJAX, improving SEO and cross-browser reliability.
Logistic and Last-Mile React Native App
Upwork (Contract) | Boston, MA
Architected a distributed AI-native logistics platform built with React Native and Kubernetes, enabling real-time dispatch and intelligent routing across thousands of concurrent delivery flows. Designed high-throughput Kafka streaming pipelines processing over 50K GPS events per minute, achieving sub-second anomaly detection and improving route deviation accuracy by 28%. Developed a RAG-powered operational intelligence layer that reduced manual escalations by 35% through contextual retrieval and automated exception handling. Implemented scalable embedding pipelines and low-latency vector search (<120ms) to power similarity-based decision augmentation for routing optimization and driver behavior analysis. Engineered a production-grade LLM orchestration framework with prompt routing, guardrails, and deterministic fallbacks, increasing automated resolution rates from 42% to 71%, while optimizing inference costs through selective invocation and token control strategies that reduced token usage by 38% and lowered monthly AI infrastructure expenses by 31%.
Education
Tech. University of Santiago, Dominican Republic
Studies in Computer Science
Zend PHP 5 Certification Engineer
Zend Technologies