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Backend engineering
Designing secure, scalable REST APIs and microservices. Web scraping, data pipelines, and authentication-hardened systems built for production traffic.
I'm Mari Kirby Castillote — a Python backend engineer based in the Philippines, designing scalable APIs, machine learning pipelines, and IoT systems. Over a decade of shipping end-to-end solutions for teams across the globe.
I build the layer between hardware and intelligence — backends that power ML, IoT devices that talk to the cloud, and the APIs that hold it all together.
For nearly 13 years I've worked as a freelance engineer out of the Philippines, collaborating with companies locally and across timezones. My focus sits at the intersection of Python backend development, machine learning, and embedded systems — the kind of problems that need someone comfortable moving between a Django codebase, a TensorFlow model, and a soldering iron.
I've built license plate recognition APIs for HIKVision cameras, workplace safety detection systems using TensorFlow, string-matching search APIs with RapidFuzz, and classification systems for industrial quality control. I've also designed PCBs, configured MikroTik routers, and led distributed teams through complex deliveries.
Remote work is how I do my best work — focused, asynchronous, and outcome-driven. I'm currently seeking mid-to-senior roles in AI engineering, backend development, or embedded systems.
Designing secure, scalable REST APIs and microservices. Web scraping, data pipelines, and authentication-hardened systems built for production traffic.
Training and deploying models for image classification, object recognition, and computer vision. Generative AI integrations, fine-tuning, and chatbot systems that actually work.
End-to-end hardware-to-cloud solutions. PCB design, firmware, and cloud-connected sensors. Comfortable from the board level up to the API layer.
Deploying and scaling containerized workloads across major cloud providers. Infrastructure as code, CI/CD, and system monitoring — plus security practices baked in from day one.
Enhanced the Tech Support Website for real-time device monitoring — online, offline, and fault states surfaced on the dashboard before clients even report an issue. Also developed an internal accounting and music royalties monitoring application for calculating client payouts on music bundle purchases.
Designed and built an ETL pipeline for an AI Voice Platform — handling ingestion, transformation, and storage end-to-end. Orchestrated workflows with Azure Data Factory, serverless compute with Azure Functions, and scalable storage on Azure Data Lake.
Built a scalable ETL pipeline for a Health Insurance App serving both insurers and clients. Automated workflows using AWS Glue with AWS S3 as the storage backbone — optimizing reliability, cost, and data integrity.
Led ML initiatives across automation and customer experience: designed web scrapers for site-reliability monitoring and competitor intelligence, built a ChatGPT-powered chatbot for tailored caravan recommendations, and shipped a sorting bot to organize uploaded content for the client's website and brochures.
Prototyped and designed PCBs for children's toys — balancing safety, cost, and manufacturability. Integrated ML algorithms for interactive play experiences, programmed NodeMCU, ESP32, STM32, and Raspberry Pi Pico targets, and managed deployments across Docker, GitHub, and MikroTik-configured networks.
Built a Python REST API on Django REST Framework to streamline big data preparation with MongoDB and Excel-backed ETL. Integrated with the MySuki Mobile App and designed a recommendation engine to boost sales and reduce low-profit item purchases.
Designed PCBs for high-fidelity flight simulators, engineered for reliability and real-time responsiveness — the kind of immersive hardware where latency is the difference between fidelity and failure.
Architected REST APIs across three distinct products: an electronic scooter rental app, a fitness activity monitoring device, and a cryptocurrency-dispensing arcade machine with secure real-time transactions. Also conducted hardware security and vulnerability assessments.
Designed Raspberry Pi–powered devices across unexpected domains — target shooting, relationship communication tools, and golfing — combining PCB design with hardware security and vulnerability assessments.
Developed Django REST APIs for system integration, engineered IoT firmware for smart devices, and designed and implemented the SPiD 10 Smart Parking Management system. Conducted hardware security assessments across the product line.
Across three client engagements: built secure REST APIs on Django REST Framework for church websites (Qwigo, ZED Networks), and developed a job-scraping API that structures postings from online platforms for job seekers and recruiters (Andre Flores).
Maintained Windows and Linux servers alongside MikroTik router configurations — DHCP, ARP, firewall, QoS, VPN, PPP, and monitoring — keeping networks performant and secure for Transparent VoIP and its clients.
Over 30+ independent projects — from GSM-enabled LPG valves and anti-theft systems to Raspberry Pi image processing for bottle cleanliness, rice crop disease detection, visually impaired assistance with image-to-text conversion, quadcopter telemetry, RFID payment systems, and IoT water level monitoring. Foundation years that shaped the full-stack hardware-to-cloud practice.
Structured coursework across the ML and data science stack — from fundamentals to advanced techniques including tree-based models, gradient boosting, and dimensionality reduction.
Focused training in prompt engineering and ChatGPT fundamentals — the toolkit behind the LLM-powered chatbots and automations I've shipped for clients.
Hands-on training across the adjacent disciplines that keep a full-stack practice sharp — cybersecurity, QA, data analytics, and no-code platforms.
Certified network engineer credentials from MikroTik Philippines — the foundation behind the routing, firewalls, VPNs, and QoS configurations I've deployed across client infrastructure.
Invited speaker at Tanauan City Colleges — sharing perspectives on where embedded systems are heading and how students can position themselves for it.
I'm currently open to mid-to-senior roles and contract work in AI engineering, backend development, and embedded systems. If that sounds like a fit, I'd love to hear what you're building.
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