Senior Backend Engineer with over nine years of experience designing and building scalable distributed systems, microservices, and cloud-native platforms. Expertise spans Java, Scala, Clojure, Kotlin, Groovy, Spring Framework, Akka, and reactive systems, with a strong emphasis on event-driven architectures, performance, resilience, and production-grade reliability. Professional highlights: Nine years of backend engineering experience Development of distributed systems handling over one million events per minute Tripled system throughput through reactive processing techniques Microservices design leveraging Akka Cluster, Persistence, Event Sourcing, and CQRS Production deployment experience with Kubernetes, Docker, AWS, and GCP Implementation of observability stacks including Grafana, Prometheus, Jaeger, and Zipkin Modernization of enterprise applications and migration to microservices Collaboration with international engineering teams across the United States, Canada, and Latin America Core technical competencies: Backend architecture and API development using Java, Scala, Clojure, Kotlin, Groovy, Spring Framework, Akka, WebFlux, Quarkus, and Play Distributed systems, microservices, and event-driven design patterns Messaging and streaming with Kafka, RabbitMQ, Redis, and GCP Pub/Sub Reactive and asynchronous processing using Akka Streams and WebFlux Event Sourcing, CQRS, stateful services, and fault-tolerant system design Cloud-native development with Docker, Kubernetes, AWS, and GCP Database design and optimization across PostgreSQL, MongoDB, MySQL, DynamoDB, and Redis Production observability, monitoring, and performance tuning Available to integrate into existing engineering teams, assume ownership of backend services, or lead the architecture of distributed systems from inception. Seeking opportunities as a Senior Java Developer, Scala Developer, Clojure Engineer, Kotlin Backend Engineer, Groovy Developer, or Distributed Systems Engineer, with a proven ability to manage production systems at scale. Open to discussion regarding relevant engineering roles.

Thanks for checking out my profile! I have lots of experience working with different technologies and I love learning. Here's a few technical things I'm proud of: - M.S. in Computer Science from Georgia Tech - Co-founder and CTO of Vistaly.com - Co-founder and developer of one of the top question apps on the App Store (Party Qs) - Contributor to the aws-cdk library - AWS Certified I love Clojure, JavaScript, serverless technologies, and open-source. You can check out my GitHub @dehli

Senior Software Engineer with 15+ years of experience building, maintaining, and improving enterprise web applications. My focus is helping teams understand complex existing systems, identify technical risks, reduce technical debt, and make pragmatic decisions about what should be refactored, improved, or left unchanged. I have strong experience with Java ecosystems, Spring Boot, software architecture, clean code, design patterns, SQL, APIs, and integration between complex systems. Throughout my career, I have worked on systems where reliability, maintainability, and scalability were critical, including payment orchestration platforms, e-commerce solutions, analytics systems, and high-volume applications. My experience includes: - Architecture reviews and technical decision-making - Code quality improvement and code reviews - Refactoring legacy applications safely - Java/Spring Boot backend development - REST API design and system integrations - Database modeling and advanced SQL - Agile software development practices Selected experience: - Designed and developed a payment orchestration platform for Casas Bahia, integrating multiple payment gateways and managing complex payment flows. - Developed an e-commerce observability platform focused on data analysis, anomaly detection, and operational insights. - Worked with large Brazilian companies on B2C platforms and high-scale web applications. I believe good software architecture is not about rewriting everything — it is about understanding the current system, identifying the real problems, and creating a practical improvement roadmap.

I'm a full-stack engineer and architect who has spent years designing, shipping, and modernizing web applications in Clojure, TypeScript, Laravel, and AWS. Most recently I built a CMS and social-publishing platform end to end (TypeScript, Nest.js, AWS, CDK) by directing Claude and Codex. I owned the architecture, code review, and delivery while the agents wrote the code. I ship real production software by orchestrating AI coding agents, not just demos and prototypes. The hard part was never the AI. It's the 15+ years of engineering judgment that tells it what good looks like. What I bring: • Senior architecture and full-stack delivery: distributed systems, serverless, AWS (CDK and infrastructure-as-code), and API design. • AI-agent orchestration that actually ships: agent workflows, automated code review, and dependency hygiene. • Internal knowledge systems: I build tooling that ingests a team's meetings, Slack, and specs and makes it all semantically searchable, so organizational knowledge becomes a first-class, findable asset instead of something buried in scattered threads. • Deep range across languages: Clojure, TypeScript, and PHP/Laravel. I created ParaTest, which ships with Laravel and has over 100 million downloads. • Fast, reliable, understandable systems, and a habit of leaving teams better than I found them. If you've got something real to build, or a system that needs to get faster, cleaner, or more modern, let's talk.

Hi. I am a software developer with strong experience in data statistics and data analysis using R and Python. I practise: - preprocessing of data - exploratory of data analysis - model development - model evaluation - model visualization

Since 2007, I've specialized in back-end programming and database administration with the Wordpress and Django frameworks. I am fluent in PHP, Python, and functional programming as well as PostgreSQL and MySQL. I also have experience in: - AWS - JVM programming - Ecommerce and marketing - SEO - Server configuration and administration I've made contributions to several OSS projects and am one of the primary authors of the Satchmo ecommerce framework. Check out my open-source work at at github.com/john-shaffer

Bridging the Gap Between Enterprise Software & Intelligent Hardware. With over 9+ years of experience building high-scale digital ecosystems, I specialise in creating software that doesn't just store data, but understands it. I am currently completing my MSc in Computer Science at the University of Nairobi, where I focus on the intersection of Edge AI, Robotics, and Advanced Data Analytics. Whether you need a robust e-commerce platform, a real-time analytics dashboard, or an AI model deployed on custom hardware, I deliver production-ready code optimised for performance. Core Areas of Expertise 1. Computer Vision & AI Engineering I provide end-to-end solutions for industries ranging from autonomous robotics to smart infrastructure: Advanced Image Segmentation: Expertise in semantic and instance segmentation using the latest YOLO26, U-Net, and Mask R-CNN for high-precision tasks like medical imaging, industrial defect detection, and wildlife density mapping. Edge AI Optimisation: I specialise in model compression and optimisation. I convert PyTorch/TensorFlow models to ONNX and TensorRT, achieving 30+ FPS on edge devices by leveraging NMS-free architectures. Intelligent Pre-processing: I develop custom OpenCV pipelines to solve "real-world" lighting issues. I have built proprietary adaptive filters that normalise CCTV footage in real-time, reducing downstream AI errors and cutting cloud bandwidth costs by processing data at the edge. Autonomous Navigation: Experience developing vision systems for UAVs and mobile robots, including obstacle avoidance, feature tracking, and nocturnal sensing using thermal/RGB fusion. 2. Data Engineering & Analytics I bridge the gap between "Edge" data collection and "Cloud" business strategy: Fleet & Operational Analytics: I build complex Power BI ecosystems powered by Python (Pandas/NumPy) to analyse large-scale institutional data—such as fleet efficiency and routing optimisation for government-level transportation systems (e.g., NTSA). Real-time Dashboards: Transitioning hardware-collected telemetry into interactive, executive-ready visualisations. 3. Full-Stack Web & Mobile Development A decade of commercial experience building secure, scalable applications for enterprise clients. Web: ClojureScript, Node.js, Next.js, and React. Expertise in Hasura, Nhost, and AWS/GCP. Mobile: High-performance apps using Swift, Kotlin, Flutter, and React Native. Backend: Robust API development and complex operation management systems. Technical Stack NVIDIA Jetson Specialist: Deep knowledge of the Orin Nano Super (67 TOPS), leveraging the Ampere architecture for Generative AI and Vision Transformers at the edge. Core Stack: Python, C++, OpenCV, PyTorch, MobileNetV2, Clojure/Lisp. Hardware Integration: CSI Camera interfaces, OLED modules, ESP32/Arduino controllers, and 3D-prototyped modular upgrades. Selected Project Highlights Wildlife Conservation AI: Developed a thermal-imaging drone system for nocturnal animal counting and plantation inventory using custom segmentation models. Infrastructure Efficiency: Designed a Power BI analytics engine for large vehicle fleets to identify a ~15% reduction in fuel waste. Smart Surveillance: Built a deployment-ready "Vision Pre-processor" that dynamically adjusts camera frames for uniform footage, specifically for AI-enhanced CCTV systems. Why Work With Me? I bring a researcher’s precision and a commercial engineer’s speed. My work is built on a foundation of 9 years of enterprise-grade projects, ensuring that even the most "experimental" AI or electronics projects are delivered with professional documentation and stable architecture. Note: Much of my commercial work is under NDA, but I am happy to discuss my technical approach and share non-sensitive case studies from my MSc research. Let’s build something intelligent. Reach out to discuss your project!

Helping companies build scalable, reliable, and cost-efficient data platforms. I'm a Principal Data Engineer with 11+ years of experience designing and implementing modern data engineering solutions for startups, fintech companies, healthcare organizations, and enterprise businesses. I've helped organizations migrate legacy systems, build cloud-native data platforms, optimize processing costs, and deliver production-ready analytics pipelines. My expertise includes designing end-to-end data architectures, building batch and streaming pipelines, implementing Data Lakes and Lakehouses, and automating infrastructure using Infrastructure as Code. What I can help you with ✔ Databricks Development & Optimization ✔ Apache Spark (PySpark & Scala) ✔ Azure Data Factory (ADF) ✔ Azure Data Lake Storage (ADLS) ✔ Delta Lake & Delta Live Tables ✔ AWS (EMR, Glue, Athena, Lambda, S3) ✔ Data Warehouse Design ✔ ETL / ELT Pipelines ✔ Data Migration ✔ Data Modeling ✔ Terraform & Infrastructure Automation ✔ SQL Performance Optimization ✔ Python Development ✔ CI/CD for Data Platforms ✔ Airflow Workflow Automation ✔ AI-powered Workflow Automation (Cursor, Claude, MCP, n8n) Recent accomplishments • Reduced operational costs by 90% by redesigning SCD implementation using Delta Live Tables. • Led the architecture and delivery of financial products including Loans and Credit Cards. • Migrated enterprise data warehouses to cloud-native lakehouse architecture. • Built scalable reconciliation frameworks using Databricks and Airflow. • Implemented Terraform-managed Databricks infrastructure for improved governance and scalability. • Designed enterprise-grade data platforms for healthcare, fintech, and retail organizations. My Skills Sets are: SQL, Apache Spark, Hive, Hadoop, Excel, Shell Scripting, AWS EMR, Ec2, S3, cloud formation, Clojure, MongoDB MySQL, Airflow.

Senior Backend & Data Engineer with 20+ years of experience building reliable, scalable systems for finance, banking, quantitative research, and enterprise applications. I specialize in backend architecture, distributed data processing, APIs, and database-intensive applications. I work comfortably across the full lifecycle: system design, implementation, optimization, troubleshooting, and long-term maintenance. My experience includes: • Financial systems and banking platforms • Quantitative and data-intensive applications • High-performance backend services and APIs • SQL optimization and database architecture • Distributed processing and large-scale data pipelines Core technologies: • Python, TypeScript/Node.js, C#, Haskell, F#, Clojure • Django, .NET, REST APIs • PostgreSQL, SQL Server, CockroachDB, MongoDB, Cassandra, kdb+/q • Docker, Linux, Git, scripting and automation Clients value my ability to work independently, understand complex business domains quickly, and deliver production-ready solutions with minimal supervision.

Hi! I'm a passionate Full-Stack Developer with 4+ years of professional experience helping businesses streamline their operations and boost efficiency through custom software solutions. What I Bring to Your Project: 💼 Proven Business Impact: Increased sales efficiency by 40% for a Peruvian company by developing a custom sales management system Built a multi-quote comparison platform that serves thousands of users in Costa Rica Led development teams to deliver complex projects on time and within budget 🛠️ Technical Expertise: Backend: Java, JavaScript, TypeScript, Go, Clojure, Elixir Frontend: React, Angular, responsive web applications DevOps: CI/CD pipelines, cloud deployment, infrastructure automation Leadership: Team coordination, technical decision-making, project planning My Approach: ✅ Business-First Thinking: I don't just code, I understand your business needs ✅ Clean, Scalable Code: Solutions built to grow with your business ✅ Clear Communication: Regular updates and transparent progress tracking ✅ Problem Solver: From concept to deployment, I handle the full development cycle