Based inGdynia, PL
RoleFront End Engineer
In IT since2017 · 7 yrs
Currently@ Cognizant

Hey, I am Aleksander Stefański. Frontend. React × TypeScript Developer.

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See my experience Contact me
01 — About me

A frontend developer
with a fullstack mindset.

I build interfaces that
feel inevitable — the
kind you don't notice,
until you do.

Frontend Developer with 7 years in IT and 5+ years of hands-on frontend experience — specializing in scalable, data-intensive web applications in React, TypeScript and JavaScript. A strong full-stack foundation in Java and Spring lets me collaborate effectively across microservices, API layers, and end-to-end system architecture.

7 yrs in IT · 5+ FE 3 sectors · Finance / Industrial / Enterprise
Aleksander Stefański — portrait
Portrait · Gdynia, PL 54.52°N / 18.53°E
@ Cognizant
Daily stack
ReactTypeScriptRedux ToolkitTanStack React QueryZustandComponent LibrariesCypressJest / RTLClaudeSCSSVite
Also fluent in
JavaSpringJenkinsAstroWebpackTailwind CSSReact Hook FormFormikYup / ZodEslintPrettier
Industries
  • 01 Financial Services
  • 02 Industrial / Supply Chain
  • 03 Enterprise Web
  • 04 SaaS Platforms
  • 05 Public Sector
Education
M.Sc.
Computer Science
Gdańsk University of Technology
B.Sc. 2014–17 · M.Sc. 2017–19
AI Toolbox
Claude CodeAntigravityStich Google AIGitHub CopilotClineClaude DesignMCP ServersNano Banana
prompt-first development
A little about me

I've worked on complex enterprise systems for global clients in the industrial and financial sectors — leading core React applications that render large-scale datasets (1M+ records, 20–30k+ map points), shipping features on platforms used by hundreds of thousands of users worldwide, and contributing to cross-service architectural decisions. Beyond the code I mentor junior developers and have temporarily covered Team Lead (team of 6) responsibilities. Outside of work I'm a hands-on tinkerer: home automation, DIY, films, sports and games.

01 / 05Home Automation
node.living-room · online
Home Automation · DIY · Films · Sports · Games
02 — Experience

Where I've worked,
and what I shipped.

Click any row to expand the experience
2022 — Now
Cognizant Current
Front End Engineer Gdynia, PL · Hybrid
P.01 · Scope

Building scalable, data-intensive React applications for global clients in financial services and industrial distribution. I lead frontend architecture, render large-scale datasets, contribute to cross-service design decisions, mentor juniors, and have temporarily covered Team Lead (team of 6) during a hiring transition.

P.01. 01 2023 - Now

Global financial platform

Developed and enhanced features for a high-traffic React application serving hundreds of thousands of users worldwide. Collaborated on technical needs assessment and cross-service architectural discussions; supported Tech & Team Leads in coordination and processes.

ReactTypeScriptRedux ToolkitTanStack React QueryCypressSCSSJest / RTLJenkinsCross-service
Sector Finance
Users 100k+
P.01. 02 2022 - 2023

Industrial data platform — US distributor

Led the development of a core frontend application processing and visualising massive datasets — 1M+ records and 20–30k+ points rendered on Google Maps, with table-driven filtering and sorting over streaming API data. Designed maintainable UI architecture, implemented key components reused across the app, and integrated tightly with backend teams on API contracts.

ReactTypeScriptGoogle Maps APITanStack React QueryZustandSCSSJest / RTLWebpack
Sector Industrial
Role Lead FE
P.01. 03 2022 - Now

Mentoring, knowledge sharing, Team Lead support

Provided mentorship and knowledge sharing for developers transitioning into React and modern frontend development. Supported the Tech Lead and Team Lead in facilitating meetings and team coordination, and temporarily assumed Team Lead responsibilities (team of 6) during a hiring transition.

MentoringLeadershipKnowledge Sharing
Covered Team Lead
Mentored Juniors
P.02 · Scope

Core member of the architecture team — defining frontend strategy and architectural direction for multiple enterprise projects. Built shared component libraries, owned CI/CD pipelines, and authored guidelines that became the team's reference (Public Sector clients via Netcompany).

P.02. 01 2020 - 2022

Multi-step forms engine

Created a reusable multistep form engine in React used across multiple enterprise applications — designed for configurability, reuse, and clear validation contracts.

ReactTypeScriptRedux Toolkit / SagaStyled ComponentsaxiosJest / RTLFormikWebpackESLintPrettierSpring Boot (backend)
Scope Platform-wide
P.02. 02 2020 - 2022

Shared UI component libraries

Configured multiple npm packages and authored major components consumed as shared libraries across many React projects org-wide. Helped define frontend strategy for the wider multi-project ecosystem.

npmReactStyled ComponentsComponent LibraryWebpackESLintPrettierTypeScript
Adoption Many projects
P.02. 03 2020 - 2022

CI/CD & developer experience

Created, maintained, and repaired CI/CD pipelines in Azure DevOps. Wrote documentation, guidelines and best practices; ran seminars to share knowledge across teams.

Azure DevOpsGradleJava
Pipelines Owned
P.03 · Scope

Eight months across three rotations — started as a Java intern, moved to backend, then into frontend. A fast-paced introduction to production code, microservices, and modern frontend tools and workflows.

P.03. 01 2018

Product & charts dashboard — Frontend

Built features for a system designed to manage product data, including interactive charts for presenting business information. Strengthened practical experience with modern frontend tools and workflows.

AngularJSJavaScriptRxJsHTML5FirebaseCharting Libraries
Stack FE
Duration 3 mos
P.03. 02 2017

Microservice data crawler — Backend

Contributed to a microservices system responsible for discovering and collecting data from external websites, then exposing aggregated information through well-structured REST APIs for internal consumers.

Java 8Spring BootSpring CloudMicroservicesREST
Arch Distributed
P.03. 03 2017

Secured REST API & Skype Bot — Intern

Contributed to the design and development of a secure REST API used for internal communication and data exchange. Built a Skype Bot as an additional interaction channel. Worked in 2-week Scrum iterations.

Java 8Spring SecurityScrumSkype Bot SDK
Process Agile
03 — Personal Projects

What I build
on my own time.

Personal · Live MyTradeWorld Solo project 2026 — Now

MyTradeWorld —
your whole portfolio,
honestly measured.

No. 01 Featured
Live data feed · MyTradeWorld
Consolidated net worthHoldings with live FXReturn metrics & benchmarkBelka-tax estimate
01 / 04 Consolidated net worth
Development
Anthropic Claude Code Driven
Project
Only personal use
Trade Markets
World Trade, Bonds, Funds
Project number
01
Solo, full-stack
P.01 · Overview

MyTradeWorld solves the “my money is scattered everywhere” problem for the Polish DIY investor. It ingests an XTB .xlsx export (or universal CSV / manual entry), normalizes everything to PLN via NBP reference rates, and gives one consolidated view of net worth, allocation and performance across equities, ETFs, treasury bonds (with correct coupon accrual) and NAV-priced funds — including IKE/IKZE tax wrappers. The focus is honest numbers: it separates Time-Weighted Return from Money-Weighted Return / XIRR, overlays your growth against WIG, WIG20, mWIG40, S&P 500 and MSCI World, splits foreign-holding P/L into market move vs. currency move, and estimates the 19% “podatek Belki” per tax year. Every import is previewable and reversible, with an append-only audit trail, and the app is fully bilingual (PL/EN) and RODO-compliant.

Project tech stack
Next.js 16React 19TypeScriptTailwind CSS v4SupabasePostgreSQLnext-intlRechartsZodDecimal.jsSheetJS / PapaParseNBP APIVitestPlaywrightGitHub ActionsVercel
Personal · Live hotsmeta.pl Solo project 2026 — Now

HotsMeta —
the data dashboard
for Heroes of the Storm.

No. 02 Featured
Live data feed · hotsmeta.pl
Global Hero StatisticsPlayers LeaderboardPlayer ProfileHero Talent Analysis
01 / 04 Global Hero Statistics
Matches analysed
8.5K
Heroes tracked
90
Parsing
Real-time
Project number
02
Solo, end-to-end
P.02 · Overview

Outside of client work, I'm shipping HotsMeta — an end-to-end stats platform for the Heroes of the Storm community. Built solo, from the TypeScript replay parser through to the React frontend, the leaderboard backend, and the public marketing site. Global hero statistics, player MMR leaderboards, deep player profiles with role and phase analysis, and talent pick/win-rate breakdowns for every hero. Positioned as a modern HotsLogs / HeroesProfile alternative with real-time replay parsing.

Project tech stack
ReactTypeScriptElectronNodeJSSupabaseFirebaseReact QueryZustandShadcn/uitailwindcss@astefanski/storm-parserAntigravityViteStich Google AI
More work in progress · check back later
Get in touch about a collab
04 — Get in touch

Let's talk
about what
you're building.