
Ostap
From United States (UTC-4)
14 years of commercial experience
Lemon.io stats
10
projects done3874
hours worked1
offers now 🔥Ostap – React, Node.js, PHP
Look no further in your search for the finest full-stack developer because Ostap is here. Passionate about JavaScript he can build architecture from scratch without hesitation. With rich expertise in the IT industry, complemented by recent AI experience and numerous successful projects under his belt, Ostap brings a strong CTO and backend background, making him adept at solving complex tasks.
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May 22Direct hire
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Let’s get started today!Experience Highlights
AI Systems Architect & Full-stack Developer
An emotionally intelligent system built to power brand experiences through poetic, symbolic interaction. It merges local language models with evolving memory and emotional recall, enabling deep personalization for wellness, fashion, and immersive storytelling applications.
- Developed vector memory engine with Mistral + Weaviate for personalized recall;
- Built resonant interaction layer using symbolic inputs and emotional cues;
- Designed modular personas and frontend experience with Next.js + Supabase;
- Enabled emotional brand alignment through state-aware memory traces.
Full-stack Developer / Data Engineer
A large-scale healthcare platform serving users across the USA and Canada. The platform connects patients with medical services and clinical trials, offering personalized communication and advanced data processing.
- Built a high-performance caching solution to process over 500,000 data points per week for complex statistics using BullMQ queueing;
- Managed weekly delivery of 200,000+ personalized emails, incorporating dynamic charts (pie, line, bar) and geospatial maps;
- Developed automated patient appointment reminders via SMS and email;
- Engineered a system to gather post-appointment reviews, transforming and anonymizing client data using LLMs (OpenAI).
Full-stack Developer
A public-facing platform developed for a regional government in Ukraine to display open data, statistics, and performance ratings of municipalities. The system includes visualizations (charts, maps), public service information, and an admin panel for managing content and configurations.
Multiple development iterations through 2022–2025
- Designed and implemented full-stack architecture using Next.js and NestJS;
- Integrated APIs from other government services to import real-time community data;
- Configured server deployment and CI/CD pipelines using Vercel and Railway;
- Built interactive dashboards showing community statistics, development metrics, and rankings;
- Developed an admin panel for managing datasets and publishing updates;
- Added module for public medical institution listings, including searchable directories and statistical overviews;
- Implemented email services using Mailgun for admin alerts and public data export requests.
Front-end Developer
Project 1: Dynamic Form SaaS Platform ("ReFRMD")
A rebuilt and extended SaaS application enabling users to create highly dynamic, conditional forms adaptable across industries (e.g., agriculture, risk management). Designed to gather complex input data and feed into a reporting and analytics system.
Project 2: Product Presentation Platform for Tablets
A SaaS tool for merchants to present custom product information (e.g., intraoral scanners) via tablet-based apps, with an admin panel for presentation creation and international customization.
Project 1: Dynamic Form SaaS Platform ("ReFrmd")
- Migrated frontend architecture from React to Next.js;
- Developed complex dynamic form engine with conditional logic and reusable subforms;
- Implemented JWT-based user authentication and user management features;
- Integrated with existing APIs shared with mobile app clients;
- Built customizable reporting views and analytics models for submitted form data.
Project 2: Product Presentation Platform for Tablets
- Built responsive tablet-oriented layouts for dynamic slide presentations;
- Developed admin dashboard to create, manage, and reuse branded presentation slides;
- Implemented multilanguage support and country-specific settings (including data restrictions);
- Integrated the platform with corporate app hosting environments for deployment of customized builds.
Front-end Developer
A web system for managing loading and unloading cargo ship containers for a major logistics company. The platform includes tools for ship crews to register containers during operations, as well as management features for reporting, legal documentation, and process oversight.
- Designed and implemented the frontend architecture using React.js and Tailwind CSS;
- Integrated frontend with backend services and legacy system APIs;
- Developed dynamic forms for ship crews based on ship codes and cargo specifications;
- Implemented Supabase-based user authentication and access control;
- Created frontend logic for generating various PDF documents (reports, legal paperwork);
- Ensured responsive design and usability across roles (crew and management).
Front-end Developer
A centralized platform aimed at helping asylum seekers and refugees in Canada understand their rights and access essential services and legal resources.
- Implemented new front-end features based on evolving user needs and accessibility standards;
- Integrated the front end with an existing backend API, ensuring data consistency and UI responsiveness;
- Diagnosed and resolved critical bugs across multiple components;
- Ensured accessibility and compatibility across devices for a vulnerable user base.
Full-stack Developer
A SaaS platform designed to connect nurses with professional coaches, enabling secure video communication and appointment scheduling.
- Designed and implemented both frontend and backend architecture from scratch;
- Set up and configured backend servers for production deployment;
- Integrated Mailgun for transactional email functionality;
- Built core user flows including nurse-coach matching and video session support;
- Delivered a stable MVP on a tight deadline after a previous version failed to meet quality standards.
Front-end Developer
An AI-driven portfolio platform that helps students showcase their strengths by aligning skills with real evidence, building credibility and visibility through a smart, skills-based portfolio.
- Implemented modern, responsive frontend modules based on Figma design mocks;
- Debugged and refactored legacy frontend code to improve stability and maintainability;
- Collaborated closely with backend developers to ensure smooth API integration and feature delivery;
- Enhanced UI consistency and user experience across portfolio-building flows.
Lead Developer
SaaS learning platform designed to help startups create educational content, assign personalized learning paths, and track real-time training performance and engagement metrics.
- Developed full-stack architecture, covering both frontend and backend systems;
- Set up server infrastructure and deployment pipelines using Railway and Vercel;
- Integrated external services, including Notion API and Mailgun, to enhance content workflows and communication;
- Delivered a modular, scalable platform adaptable to various startup needs.
Full-stack Developer
A DeFi platform that builds distributed asset pools for player-owned economies, allowing NFT holders to earn passive income and contribute to a circular crypto economy. The platform lowers the barrier to entry for millions exploring crypto and the Metaverse.
- Developed and maintained both frontend and backend features across the platform;
- Rewrote critical business logic previously written in Python, migrating it to the TypeScript ecosystem;
- Wrote unit tests and ensured feature stability;
- Participated in team code reviews and managed PR quality;
- Helped synchronize frontend-backend API flows in a real-time web3 environment.
Tech Lead
A specialized video-based coaching platform where medical professionals can improve their communication skills. Doctors engage in interactive training sessions with standardized patients (actors), who provide structured feedback on performance, simulating real-life consultations.
- Led full-stack development efforts and mentored junior developers throughout the project;
- Designed and implemented critical frontend and backend features for real-time video sessions and feedback workflows;
- Wrote and maintained test suites; prepared internal documentation for future developers;
- Managed code quality through peer reviews and technical planning;
- Developed modules for coaches and doctors, performance analytics, and actor review tools.
Lead Developer
A large-scale ERP system developed for Syngenta Corporation, a global leader in agricultural science and technology. The system supports decision-making and operations for agriculture professionals by integrating weather data, crop management tools, and enterprise systems.
- Developed and maintained a complex ERP system with over 80 interrelated data models and tens of millions of records in the database;
- Implemented bidirectional integration with Syngenta's global corporate ecosystem;
- Integrated with Meteoblue, a global weather data provider;
- Established two-way sync with Cropio, a crop and field management system;
- Built support for 7 user roles with customized permission levels;
- Contributed to the development of 10+ functional modules, including analytics, logistics, and agricultural task planning.
Lead Front-end Developer
An AI-powered platform for visual content analysis, providing advanced tools for analyzing images and video content at scale. It serves use cases in retail, advertising, and media with data-driven visual intelligence.
- Developed and optimized frontend components using React.js;
- Worked closely with design and AI teams to implement dynamic UI components;
- Contributed to building a smooth and responsive user experience for data-intensive interfaces;
- Ensured performance and compatibility across devices and browsers.
Full-stack Developer
A niche B2B/B2C marketplace designed for the German precious metals market. It enables seamless trading of metals with real-time pricing, multi-role access, and integrated payment systems.
- Developed user panels for various roles: admin, operations, vendors, and customers;
- Integrated real-time price feeds from metal pricing providers;
- Implemented secure payment gateway support via PayPal and Stripe;
- Set up Gmail-based authentication for streamlined user onboarding and login;
- Ensured smooth UX and operational workflows for both buyers and sellers.
Tech Lead and Co-founder / CTO
A platform designed to connect startups with the right talent and investors in the Nordic ecosystem. The platform became a major hub for startup hiring and visibility — and was later acquired by TheHub.io, expanding its impact in the region.
- Led the development and implementation of a long-term technical roadmap;
- Built internal processes and workflows for a growing development team;
- Oversaw technical development from architecture to deployment;
- Managed both local and remote development teams;
- Prepared technical presentations and investor reports;
- Participated in public presentations and startup events;
- Recruited, interviewed, and grew the internal tech team.