Available for new opportunities
Hi, I'm Bartłomiej
Software
Developer
@ bkosinski.dev
4+ Years of Experience
01
/
About Me
I build applications from the ground up, always with a touch.
Specializing in full-stack development with a focus on frontend architecture, including monorepos, micro-frontends, module federation, and monolithic applications.
Led a frontend team, guiding architectural decisions, code quality, and collaboration across complex projects.
To me, good engineering isn’t about chasing the newest tools, but about choosing the right tools for the right problems — and understanding them deeply enough to use them with confidence.
I also value collaboration and , believing that the best solutions often come from teamwork and open communication.
In my free time, I explore new that broaden my knowledge, and when I’m not coding, you’ll probably find me reading , experimenting in the , exercising, or spending time with my dog.
TypeScript
Type-safe approach
Seamlessly bringing API types into the web environment with OpenAPI, monorepos, and automated code generation, regardless of the programming language or framework.
Performance
Optimizing build and test times by choosing the right tools, leveraging caching, and ensuring effective code-splitting, while continuously identifying and eliminating performance bottlenecks.
Testing & Quality
Ensuring high code quality through unit, integration, and end-to-end testing. Catching issues early and maintaining confidence when refactoring or shipping new features.
Security
Applying modern security standards and best practices, including secure authentication flows, proper data validation, monitoring including OpenTelemetry and safe API communication.
02
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TechStack
The tools and technologies I use to design, deploy, and operate infrastructure at work.
Frontend
Vite Vite
React React
React Router React Router
Next.js Next.js
TanStack TanStack
Redux Redux Toolkit
Apollo GraphQL Apollo Client
Turborepo Turborepo
Nx Nx
Pusher Pusher
MDX
UI / Styling
Sass Sass
Tailwind CSS TailwindCSS
Motion
Shadcn UI
Radix UI Radix UI
Form / Validation
TanStack TanStack Form
React Hook Form React Hook Form
Zod Zod
ArkType
Backend
Node.js Node.js
Express Express
NestJS NestJS
Fastify Fastify
Node-RED Node-RED
Laravel Laravel
Testing / Documentation
Jest Jest
Vitest Vitest
Testing Library React Testing Library
Playwright
PHPUnit
Nextra Nextra
Storybook Storybook
Databases / ORM
MySQL MySQL
PostgreSQL PostgreSQL
MongoDB MongoDB
Redis Redis
Drizzle Drizzle
Prisma Prisma
Laravel Eloquent
Containers & CI/CD
Docker Docker
GitHub Actions Github Actions
Recent Certifications
NestJS Fundamentals
Official NestJS Courses
Jan 2026
Credential
NestJS Advanced Concepts
Official NestJS Courses
Jan 2026
Credential
TypeScript Workshop
TotalTypeScript
Expected Jan 2026
In Progress
Learn Kubernetes
Boot.dev
Expected Feb 2026
In Progress
03
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Career Journey

  1. Full Stack Developer, Frontend Lead

    Link-Point
    Jan 2023 - Present
    Remote
    Key Achievements
    - Designed and implemented modular architectures for on-premise ERP and MES systems using a monorepo approach (e.g., Turborepo, Nx)
    - Led a team of frontend developers, overseeing task distribution, code reviews, and technical decision-making
    - Built user interfaces with React and TypeScript, creating responsive designs, and enhancing user experience
    - Developed and maintained backend services in Node.js and PHP, focusing on relational databases, data integrity, and event-driven architecture
    - Enhanced existing systems to meet business and reliability requirements, emphasizing unit and end-to-end testing
    - Integrated ERP and MES systems with industrial devices (e.g., PLC, OPC UA)
    - Created and maintained internal technical documentation using OpenAPI and MDX, improving knowledge sharing and accelerating onboarding of new team members
    Docker
    Laravel
    MySQL
    NestJS
    Node.js
    PHPUnit
    React
    Redis
    Slim
    TypeScript
    Vitest

  2. Frontend Developer

    Link-Point
    Jan 2022 - Dec 2022
    Poland
    Key Achievements
    - Developed and maintained web applications using React, applying core concepts such as hooks, context, and component lifecycle
    - Rewrote and refactored a legacy frontend codebase into TypeScript, significantly improving code quality, developer experience, and scalability
    - Managed project tooling and configuration, including bundlers and build optimization
    - Collaborated on backend-related tasks using Laravel and SQL, enabling efficient data handling and API integration
    Laravel
    MySQL
    React
    Sass
    TypeScript

  3. Information Technology and Computer Science

    Technical College for Computer Science
    2017 - 2021
    Poland
    Key Achievements
    - Finalist of Polish Technical Innovation and Invention Olympiad in category didactic help (co-creator of educational web platform Live-Text for online learning and examing)
    C++
    JavaScript
    MySQL
    PHP
    WebSockets
04
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Projects
process-diagram
Shipment Tracking
Vague shipment statuses from the official app are resolved by automating tracking via Poland Post's public SOAP API, with email notifications for each update.
process-diagram
app
NestJS
React
SOAP
TanStack Start
TypeScript
process-diagram
Book Collections
To address duplicate book orders and incomplete entries on platforms like Goodreads, a personal library management system tracks the entire collection, including multilingual titles, and efficiently manages reading history.
process-diagram
app
app
ArkType
ClickHouse
Docker
Fastify
GraphQL
Kafka
Mercurius
NestJS
PostgreSQL
React
Redis
TanStack Start
TypeScript
process-diagram
Portfolio
Motion
Next.js
React
TailwindCSS
A personal portfolio built with Next.js and React to showcase projects and experience. It features smooth animations with Motion and a clean, responsive design.
GitHubView on GitHub
WebSocketKit
Issues with missing type definitions and unstable real-time listeners in the provided SDK are resolved by introducing a type-safe abstraction that centrally manages listener lifecycles, ensuring unsubscribe is triggered only when no active listeners remain.
Pusher
TypeScript
Vitest
npmView on npmGitHubView on GitHubView documentation