Ingests and aggregates millions of daily events at the edge, serving sub-second dashboards.
Maciej Fender
I build reliable web systems end to end — from data models and APIs to the interfaces on top of them. I care about clear boundaries, tests that document intent, and code that the next person can change without fear.
This site collects my projects and the technologies behind them, alongside a growing set of notes I keep while preparing for mid/senior technical interviews — part of a longer-running effort to get deliberately better at the craft.
Systems, start to finish
Fan-out delivery service pushing in-app and web-push notifications with at-least-once guarantees.
Design System & Component Library
2022–2023A typed React component library and docs site shared across three product teams.
What I build with
Languages
Data stores
Infrastructure & cloud
Tooling
Practices
Notes on getting better
Mid/senior technical questions I collect and refine while preparing. Pick a topic, then a subtopic, and expand the answers you want to test yourself on.