Mateusz
Miszczak
Frontend Engineer building production fintech in React and Next.js. Realtime trading interfaces, multi-step financial flows and admin systems.
Bitcoin
What I do day to day
The engineering behind the work below, whatever product it lands in.
- Realtime
Realtime data
Event-driven UI where prices, balances and operation states update the moment the backend knows.
- Flows
Complex flows & forms
Multi-step flows with explicit state machines, per-step validation and every failure state designed in.
- Architecture
Frontend architecture
Typed, modular React and Next.js apps in a monorepo, with shared packages instead of copied code.
- Platform
CI/CD & IaC
Pipelines that check and ship every change, and frontend infrastructure defined in code.
Selected work
Key production areas I worked on across fintech applications, delivery and infrastructure, and CMS-driven websites.
My Journey
From freelance work to production fintech
I started with client websites, photography portfolios and data tools, then joined a production fintech team. My scope has grown from single features to owning larger areas end to end, from trading interfaces and withdrawal flows to the CI/CD and frontend infrastructure behind them.
Freelance and commercial projects
Responsive websites for clients and agencies, including a photographer's portfolio scoring 99/100 Performance and 100/100 SEO in Lighthouse, plus marketing sites and data tools.
Production fintech applications
Trading interfaces, wallet views, withdrawal flows, admin systems and WebSocket data synchronization.
Broader scope and ownership
Owning larger features end-to-end: multi-step flows, realtime UI, CI/CD pipelines and frontend infrastructure work.