Dawid Kostrzewa

Senior Software Engineer

Building production web applications for 8+ years. Specialized in React, Next.js, and TypeScript, combining frontend expertise with fullstack ownership. Mentor and content creator.

LinkedIn
8+
years of experience
1M+
users across built apps
10+
production projects
5+
mentees hired in IT

01.About me

I'm a Senior Software Engineer with over 8 years of commercial experience building production web applications at scale (up to 1M monthly visitors). Specialized in React, Next.js, and TypeScript, combining frontend expertise with fullstack ownership (Node.js, PostgreSQL, Supabase).

I lead frontend architecture in Scrum teams, owning features end-to-end, from requirements gathering through design, implementation, and production support. I've driven performance improvements, designed scalable architectures for data-heavy UIs, and built shared Design Systems across teams.

Beyond coding, I'm a mentor and content creator. I mentor developers, lead code reviews, and create educational content reaching thousands of people. I've helped 5 people land their first jobs as Junior Frontend Developers.

ReactNext.jsTypeScriptNode.jsPostgreSQLDesign Systems

02.How I work

End-to-end ownership. From requirements analysis to production support, I take responsibility for the full feature lifecycle.

01

Requirements Analysis

I start by understanding the business problem. I work with clients and teams to translate requirements into technical solutions that genuinely address user needs.

02

Architecture & Design

I design scalable solutions with the future in mind. I choose the right tech stack, define component structure, and establish patterns the team will follow.

03

End-to-End Implementation

I deliver complete features, from frontend to backend. I write clean, tested code with a focus on performance and accessibility. When needed, I take ownership of database and API layers.

04

Optimization & Support

After deployment, I monitor performance, optimize Core Web Vitals metrics, and respond to user feedback. I build solutions that run reliably in production.

03.What I do

Projects where I combine frontend expertise with fullstack ownership, delivering complete solutions.

Large-Scale Platforms

Applications handling up to 1M monthly visitors. Next.js architecture with SSR, performance optimization, and advanced caching strategies.

Next.jsSSRPerformance

Real-Time Systems

Dispatch applications for emergency services with live vehicle and incident tracking on maps. High-frequency data streams with seamless UI updates.

RxJSMapsWebSockets

B2B & Enterprise Systems

Platforms for international sports federations, food quality control systems, solutions for finance, automotive, and legal sectors.

ReactTypeScriptREST/GraphQL

Fullstack Applications

Personal finance app with multi-tenant architecture, data encryption, analytics dashboards, and AI-based receipt scanning.

Next.jsPostgreSQLSupabase

Design Systems & Architecture

Shared component systems used across multiple teams. Standardizing patterns, leading code reviews, and establishing frontend testing practices.

Design SystemsReact Testing LibraryPlaywright

Mentoring & Education

Intensive 1-on-1 mentoring sessions in React and JavaScript. Creating technical content for thousands of followers. 5 mentees hired as Junior Frontend Developers.

ReactJavaScriptContent

8+ Years of Experience

Production web applications at scale (up to 1M monthly visitors). Projects in sports, food quality, B2B, finance, automotive, legal, and insurance sectors. Emergency services dispatch applications

Fullstack Ownership

Main specialization in frontend: React, Next.js, TypeScript, Design Systems, React Query. Fullstack capabilities: Node.js, PostgreSQL, Supabase, PayloadCMS, Prisma

Tech Leadership

Mentoring 3-5 developers at a time, leading code reviews, establishing testing practices (React Testing Library, Playwright). Helped 5 people land their first jobs as Junior Frontend Developers

Performance & Architecture

Optimizing SSR strategy, data-fetching, and bundle splitting. Designing scalable architectures for data-heavy UIs (maps, analytics dashboards, complex tables). Building shared Design Systems across teams

04.Technologies

Technologies I work with on a daily basis to deliver high-quality solutions.

JavaScript
TypeScript
React
Next.js
Node.js
Angular
PostgreSQL
Tailwind

03.Latest from blog

Check out my latest thoughts and tutorials.

How does AI improve my work and life?

How does AI improve my work and life?

21/04/2024
5 min read

AI consistently enters various spheres of our lives. As someone who eagerly explores new technologies, I decided to fully utilize the possibilities of AI in my work and daily life. In this article, I will show you how I integrated AI into my daily activities to make them more efficient.

Read more

05.Get in touch

Follow me on social media or reach out directly.