Особисті дані приховані

Tania Bilenko
Full-Stack Developer
Location: Ukraine
Email: [відкрити контакти](див. вище в блоці «контактна інформація»)
Phone: [відкрити контакти](див. вище в блоці «контактна інформація»)
Website: www.toyless.dev
LinkedIn: [відкрити контакти](див. вище в блоці «контактна інформація»)
GitHub: github.com/ToyLess78

Summary
Product-focused Full-Stack Developer specializing in end-to-end delivery of new products
and the support and scaling of existing high-load systems. I design applications from scratch
— from idea and system design through to production release — and professionally stabilize
and bring AI-assisted and legacy projects to production-ready state: conducting technical
audits, eliminating technical debt, optimizing performance, closing security vulnerabilities,
and introducing practices that improve system stability and maintainability. Proficient in
React.js, Next.js, React Native, and Node.js. Deep expertise in REST API architecture and
integration, designing scalable relational and NoSQL databases, and optimizing backend
and frontend performance (query tuning, caching, Core Web Vitals, and API efficiency). As a
solo engineer, I can independently manage the full product lifecycle — from requirements
analysis and architectural decisions through development, deployment, monitoring, and
ongoing evolution. I work effectively in cross-functional teams (developers, designers, QA)
and communicate directly with founders, product owners, and business stakeholders to
translate product ideas into reliable, user-focused solutions.

Skills
Core Stack: JavaScript (ES6+), Node.js, TypeScript, React.js, Next.js, Nest.js, Express.js,
React Native
State Management & Data Fetching: Redux Toolkit, RTK Query, TanStack Query, Context
API, Zustand

UI & Styling: HTML5, CSS3, SCSS, Tailwind CSS, ShadCN, Styled Components,
PrimeReact, IcoMoon
Backend, API & Databases: REST API, GraphQL, Socket.io, PostgreSQL, Redis, MySQL,
MongoDB, Knex, Objection, Fastify
CMS & BaaS: Strapi, Payload, Supabase, Firebase
Tools & DevOps: Git, GitFlow, Docker, CI/CD, Biome
Other: Dart, Flutter, LLM API integration, Technical SEO, i18n

Experience
Full Stack Developer
Freelance May 2023 – Present | Remote
Build and ship production-ready web and mobile applications using React, Next.js, React
Native, Node.js, and TypeScript, owning the full development cycle from architecture
design to deployment.
Specialize in maintaining, refactoring, and stabilizing existing high-load systems —
significantly reducing technical debt and improving fault tolerance and reliability of
production codebases.
Audit, optimize, and stabilize AI-generated code, bringing it up to strict corporate
standards for security and performance.
Design and develop UI/UX components (including complex forms, file managers, and
animations) with React, Next.js, and React Native, applying atomic architecture and
ensuring 100% code reusability.
Build high-performance landing pages and interfaces with Tailwind CSS and SCSS,
optimized for Core Web Vitals (LCP, INP, TBT in PageSpeed Insights), improving mobile
conversion and SEO visibility.
Design and implement REST APIs, backend services, and scalable data models with
PostgreSQL, ensuring stable integration between client applications, CMS platforms, and
external services.
Improve code maintainability and engineering velocity by introducing reusable
component systems and modular project structure.
Increase application performance and reduce latency through SQL query optimization,
caching strategies, and efficient data routing in high-load API platforms.

Implement technical SEO architecture for dynamic web platforms (including custom
sitemap generation, internal linking strategies, and metadata optimization), significantly
improving crawlability and search engine indexation.
Automate deployment processes by designing CI/CD pipelines and containerizing
environments with Docker, minimizing time spent on manual releases.
Work in distributed teams and communicate directly with business stakeholders to
deliver production-ready features that fully meet strategic requirements.

Projects
Kadmoo
May 2026 – Present | Contract-Based Freelance Project
Stack: TypeScript, Next.js 15, Supabase, PostgreSQL, React Query, Vercel
Problem: A live SaaS platform for an SEO agency with real users had accumulated critical
technical debt from months of AI-agent-driven development without review: degraded
database performance, zero registered migrations, and the need for urgent stabilization.
Action: Reduced Slow Queries in Supabase from 183 to 29 and Avg Rows Per Call from
162.9 to 8.0. Built a protective layer for the codebase: strict Supabase type generation
combined with formalized code quality criteria for AI agents. Closed 59+ production
incidents through root-cause diagnosis rather than symptom patching. Conducted a
security audit — identified and removed ~22 hidden debug telemetry calls that were
sending user data (emails, sessions, credit balances) to localhost. Reconstructed from
scratch an idempotent chain of ~243 SQL migrations (none had been registered in the
database), eliminating blockers that prevented schema deployment on a clean database
and Supabase Preview. Performed a full infrastructure migration (Mumbai → Stockholm)
with zero downtime: 728 MB database, 5.4 GB Storage. Restored a completely non-
functional RAG search for the client's AI agents after Google deprecated the embedding
model it was built on.
Result: CI failure rate on commits dropped by ~40%. Monthly infrastructure costs (Vercel
+ Supabase) reduced by ~25%.
UkrPas
Sep 2025 – Feb 2026 | Part-Time Contract Collaboration
Stack: TypeScript, Node.js, PostgreSQL, Strapi, REST API, Next.js, Figma, Tailwind CSS

Problem: Dynamically generated route and listing pages had limited search engine
visibility due to weak internal linking, incomplete sitemap coverage, missing indexable
content blocks, and rendering delays.
Action: Rebuilt the platform's SEO architecture: implemented a scalable sitemap system
and developed an internal linking feature that rotates weekly using native PostgreSQL
and Next.js capabilities (no cron jobs or Redis required). Deployed a self-hosted Strapi
instance for flexible SEO content management. Implemented pixel-perfect new SEO
content blocks from Figma designs and redesigned outdated elements. Created sitemap
pages without an existing design to improve crawler coverage and refactored footer logic.
On route pages, reworked FAQ block components for correct search engine indexation
(SEO/Geo), introduced Next.js Streaming to improve load times (TBT/LCP), and fixed
accessibility and HTML heading hierarchy.
Result: Stable indexation achieved for thousands of dynamically generated pages,
rendering delays eliminated (zero-render-delay), Core Web Vitals improved, and interface
load time reduced by 20–30%.
Avocado EMS/BI Dashboard
Apr 2025 – Sep 2025 | Contract-Based Freelance Project
Stack: React, TypeScript, Firebase, Supabase pgvector, Firebase Storage, Claude API,
Tailwind CSS, Recharts, Figma
Problem: The product operations team lacked a centralized tool for managing complex
gamification, AI features of the mobile app, and cloud cost control — creating risks to
Firebase infrastructure integrity and slowing internal workflows.
Action: Built a custom EMS system from scratch based on a Figma design, on top of the
existing Firebase infrastructure for a mobile wellness app. Designed and implemented
modules for managing engagement events, ranking seasons, user achievements, content,
and a knowledge base for an AI dietitian powered by Supabase pgvector. Integrated
Claude API for content generation and validation. Implemented interactive BI analytics
dashboards with Recharts, set up monitoring for Firebase triggers and analytics events,
and built a financial control system for optimizing and monitoring AI and cloud costs.
Result: Delivered a secure operational hub for the full administration cycle of the
wellness platform, automated AI model and gamification management, introduced
transparent infrastructure monitoring — enabling cloud cost control and fully eliminating
manual manipulation of the production database.
Avocado App (Mobile)

Feb 2025 – Jul 2025 | Contract-Based Freelance Project
Stack: Dart, Flutter, Go, Firebase, REST API, Figma
Problem: The mobile wellness app project was incomplete — only a few static screens
existed with no business logic or integration, while the ready Firebase infrastructure and
Go backend were not being utilized.
Action: Took over the unfinished iOS project, updated Dart and Flutter along with all
dependencies to the latest stable versions. Implemented all missing screens based on the
Figma design. Wrote client-side logic, configured state management, and fully integrated
the mobile interface with the existing Go backend via REST API, connecting Firebase
infrastructure for authentication and data persistence.
Result: Successfully completed and prepared for release a fully functional cross-platform
mobile application, fully integrated with the product ecosystem and ready for stable use
on iOS.
BeBalance
Aug 2024 – Oct 2024 | Internship Project
Role: React Native Developer
Stack: TypeScript, React, React Native, Redux, Redux Toolkit, PostgreSQL, Fastify, Knex,
Objection
Problem: The project required a stable, performance-oriented mobile tracking system for
comprehensive monitoring of physical and psychological wellbeing.
Action: Implemented modular cross-platform features using React Native and TypeScript,
structured global state with Redux Toolkit, and built async data-fetching hooks connected
to a Fastify API backend.
Result: Delivered core tracking modules that allow users to set goals and visualize
progress seamlessly.
CV Builder
Nov 2024 – Jan 2025 | Contract-Based Project
Stack: TypeScript, React, Redux, Redux Toolkit, PrimeReact, Sass, Biome
Problem: Students of the Same Code LMS platform needed a unified native tool for
quickly assembling and formatting professional resumes directly inside the dashboard.
Action: Built a modular drag-and-drop resume generator in React with multiple template
systems, atomic real-time preview updates, and dynamic server-side PDF export logic.

Result: Deployed a flexible document generation subsystem cleanly integrated into the
Same Code dashboard platform.

Education
JavaScript Developer
Binary Studio Academy May 2024 – Sep 2024 | Online Intensive Course
In-depth study of modern full-stack web architectures, advanced database management,
and mobile engineering with React Native.

Certifications
React, React Router & Redux Toolkit – Udemy
IT Security: Protection Against Digital Cyber Fraud – Google
JavaScript Algorithms and Data Structures – freeCodeCamp
Layout and Creation of Websites from Scratch – Udemy

Languages
English: Advanced
Ukrainian: Native
Russian: Intermediate