Ei Gude! I’m Artur Sopelnik

Design Systems, Tokens, AI, Tech, talks, and writes about web, privacy, and dev. I share tutorials, free resources, inspiration and also offer my help.

Ei Gude! I’m Artur Sopelnik
Is Your Child Actually Safe at Their Kita?

Is Your Child Actually Safe at Their Kita?

After years on waiting lists, most parents just feel lucky to have a spot. But luck isn't a childcare strategy. That's why kitabewertungen.de exists.

IBAN-Validieren.de – Free IBAN Validation Tool

IBAN-Validieren.de – Free IBAN Validation Tool

How I built a fast, privacy-friendly IBAN validation tool in two days. No ads, no tracking — just enter an IBAN and instantly check if it’s valid.

Figma Is Not the Source of Truth for Design Tokens

Figma Is Not the Source of Truth for Design Tokens

Why your design token source of truth should live in code, not in Figma. A case for making Figma a consumer of design tokens rather than their producer.

How to Protect Data in the Browser Using Web Crypto API

How to Protect Data in the Browser Using Web Crypto API

Learn how the Web Crypto API enables secure client-side encryption in the browser. Encrypt and decrypt sensitive data locally without relying on external servers.

Design Token Validator - Free W3C Spec Compliance Tool

Design Token Validator - Free W3C Spec Compliance Tool

Validate your design tokens against the W3C Design Tokens spec. A free, open-source tool that ensures consistency and interoperability across your design system.

How to Import Time Entries into Productive from PDF or CSV

How to Import Time Entries into Productive from PDF or CSV

A Node.js script that imports time entries from PDF, CSV, and JSON files directly into Productive via the API — no more manual data entry or transcription errors.

Projects

Real projects I built from scratch, line by line, with no AI tools. Just HTML, CSS and JavaScript.