Leonid Dzyhanskyi

Lead Frontend Engineer · Product Builder

Web platforms, AI-assisted engineering, and product architecture • Ukraine

About me

I am an engineer and product builder who makes complex systems easier to understand, operate, and improve. Over more than 14 years, I have moved from HTML and PHP to global e-commerce architecture, independent products built with Rust and Next.js, and disciplined use of AI in engineering. I am at my best when a project requires business understanding, careful work in a legacy codebase, clear system boundaries, and hands-on ownership through release.

I am not tied to a framework, language, or model provider. I choose the simplest tool that can solve the problem reliably: platform capabilities before heavier abstractions, measurement before optimization, and verified facts before conclusions.

How I strengthen teams and products

I work at Staff Engineer scope while remaining hands-on. I consider the effect of each decision on the system, the team, and the product throughout its lifecycle.

  • Systems thinking: I connect code, product needs, operational risk, and user experience.
  • Implementation ownership: I design the approach and write the critical code, staying involved beyond the architecture diagram.
  • Team enablement: I build tools, standards, and architectural boundaries that reduce repeated work across the team.

How I work: waves, signals, and noise

I do not try to turn the entire journey into a fixed plan upfront. I work in waves: each one has a clear boundary, brings a coherent set of changes together, and leaves the system in a noticeably different state. What holds up under scrutiny becomes signal; side ideas and deviations remain noise until it is time to revisit them.

  1. 01

    Direction

    I start with one meaningful outcome for the system, not a complete roadmap. It gives the wave direction without pretending everything is already known.

  2. 02

    Wave boundary

    A wave contains only changes that belong together and produce a complete outcome. Anything not needed for that outcome stays outside the wave.

  3. 03

    Signals and noise

    Verified facts, observed system behavior, and repeatable results are signals. Side ideas, assumptions, and detours are captured as noise instead of interrupting the current wave.

  4. 04

    Moving through the wave

    I carry the wave through to a working result. New signals may change the route, but I do not let every new thought expand its boundary.

  5. 05

    The new state

    At the end of a wave, I assess the system in its new state, not just the individual changes. I check what works, what actually changed, and what has become clearer.

  6. 06

    Between waves

    Between waves, I revisit the accumulated noise. Useful items may shape the next wave; the rest remains noise or falls away. An assumption becomes signal only after it has been confirmed.

How I close a wave: I lead with the result of the wave, followed by what changed, the evidence, new signals, remaining noise, and what may become the next wave.

How I choose AI models

I treat an AI model as an engineering tool, not a universal answer. The choice depends on the task, available tools and context, the cost of error, and privacy requirements.

Implementation and codebase work

Codex / OpenAI

For making changes in the real codebase, using development tools, running tests, and taking the work through verification.

Architecture and independent review

Claude

For a second perspective on complex decisions, work with long context, and an independent review of changes made with the primary model.

AI features in products

Gemini

For focused user flows in the Google and Firebase ecosystem: understanding intent, guiding a consultation, and producing structured results with predictable recovery paths.

Local and private tasks

Browser / local models

For focused tasks that should remain close to private data. If a parser, typed API, or test is more reliable, I do not introduce a model.

Responsibility rule: One primary model carries the implementation; a second model may review it independently without making changes. I make the final decision, and every important claim is checked against the code, the available tools, or the live system.

Independent products and R&D

My recent projects show how I think more clearly than a list of technologies. I build complete products and workflows that include tooling, security, documentation, verification, and release.

Developer Tooling

AIC

Active

A focused local development workspace built around a single Rust core, combining an editor, Git, terminals, notes, and project context. AI agents run through external command-line tools and keep their own models, authentication, and permissions.

  • Rust
  • PWA
  • CodeMirror
  • Git + PTY
  • Verified releases

Editor Extension

AIC Notes for VS Code

R&D

A contextual notes system for files, folders, and projects with a dedicated Markdown editor. Tables, front matter, task lists, code blocks, and Mermaid diagrams remain editable without a separate preview tab.

  • VS Code
  • Markdown
  • Mermaid
  • Sidecar context

Third-party Plugin

AIC for Standard Notes

Published

A Markdown editor for Standard Notes that stores portable plain text while displaying structure and diagrams directly in the editor. The integration uses a small, well-defined bridge to the notes API and preserves the service's data model.

  • Standard Notes
  • CodeMirror
  • Exact Markdown
  • GitHub Pages

Product Platform

Natalia Dzyhanska Training Platform

Production

A PWA for schedules, bookings, client accounts, and trainer operations. The website holds the authoritative data; Telegram and Google Chat deliver notifications and operational events, while Gemini supports only clearly defined consultation and command flows.

  • Next.js
  • Firebase
  • Telegram
  • Gemini
  • WIF CI/CD

Mobility R&D

Scootify Ecosystem

2023–2026

A multi-tenant micromobility ecosystem combining an information hub, a service platform, and a retail storefront on a shared foundation. The work brought together product experiments, operational automation, and measured optimization of browser-side computation.

  • Next.js
  • GCP
  • Web Components
  • Web Workers
  • Rust / WASM

Engineering toolkit

Web PlatformNative JavaScript (ES3–ESNext)Light DOM Web ComponentsSemantic HTMLBrowser rendering mechanics
PerformanceCore Web VitalsMain-thread budgetsWeb WorkersRust + WASM after measurement
Commerce & LegacySFCC / SFRALegacy JavaScript (ES5)Webpack / Rspack pipelinesThird-party script control
Product SystemsNext.js / ReactRust servicesGCP / FirebaseAuth, bots, and automation
InterfacesCSS Architecture / SCSSNative RTLWCAG AAResponsive PWA
AI-assisted EngineeringRole-based model selectionBounded contextCross-provider reviewEvidence-driven delivery

Cognitive profile (Gallup CliftonStrengths®)

My Gallup themes provide useful language for patterns that already show up naturally in my engineering work. Download the full report (PDF)

1Arranger
Orchestration

I quickly see relationships between people, tools, dependencies, and constraints, then rearrange them into a workable system.

2Achiever
Execution

I maintain momentum and carry work to a verified outcome. The completed loop matters more to me than the appearance of progress.

3Restorative™
Stabilization

I am naturally drawn to systems where something is not working. Diagnosing the cause and restoring stability gives me more energy than working around the problem.

Professional experience

08.2023 – PresentRaccoon

Full-Stack Developer (Consultant)

Remote

I build e-commerce interfaces on SFCC (SFRA), configure Business Manager, and integrate third-party services. I develop dynamic client-side features, work with Page Designer and Amplience, improve accessibility and performance, write technical documentation, and contribute to planning and client demonstrations.

09.2021 – PresentAlpenite/Arsenalia (Dior)

Lead Frontend Engineer

Remote

I modernized the Webpack and Rspack build pipeline with reliable tree shaking, replaced jQuery with native JavaScript, and established technical solution design standards. I also introduced dynamic image composition, measured lazy loading, and a scalable SCSS architecture with native RTL support.

2023 – 2026Scootify Ecosystem (R&D)

Principal Architect & Product Owner

Ukraine

I designed a multi-tenant micromobility platform on GCP that connected an information hub, a mobility service, and a retail storefront. The shared architecture used Next.js, Rust and WebAssembly, Light DOM Web Components, Web Workers for data processing, and messaging bots for analytics and operations.

04.2021 – 03.2022Bay Bridge Digital

SFCC Developer

France (Remote)

I stabilized a legacy storefront, refactored checkout flows to support conversion improvements, and implemented multi-currency logic and RTL layout adaptations for international markets.

05.2019 – 08.2021The Raven

Front-End Team Lead

Ukraine

I led a team building complex multilingual Angular applications, with an emphasis on consistent architecture, maintainable code, and strict type safety.

10.2015 – 02.2021Astound Commerce

Senior SFCC Developer

Ukraine

I was a core contributor to more than ten major e-commerce launches for global brands, with a particular focus on SFCC caching strategies, storefront performance, and asset optimization.

02.2014 – 08.2019Stryzhavka Online

Co-Founder & Lead Engineer (Civic Tech)

Ukraine

I co-founded and built a local civic platform for the Stryzhavka community, combining municipal information with community features. The platform was later transferred to the local government and adopted as part of its official digital infrastructure.

06.2012 – 10.2015Action Pay / Freelance

Web Developer

Ukraine

I began my career building websites with PHP and WordPress, with close attention to reliable behavior across browsers.