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Ákos Kappel
Language: en
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Experience

Three companies since 2023, from data pipelines to mobile apps.

  1. Feb 2025 to now

    1 yr 9 mos

    IGT Systems

    Full-Stack Software EngineerBratislava, hybrid(formerly IGT Consulting)

    I work on several client products at once, in teams of two to eight developers, across web, mobile and backend. I joined as an Elixir developer and now work mostly with React, TypeScript and Kotlin.

    Core3

    Business platform for projects, attendance, HR, CRM and ticketing

    • Responsible for the project management module: kanban boards with drag and drop, task permissions for creators, assignees and project leads, and Scrum and Waterfall workflows
    • Optimized the slowest pages after user complaints: found the slow parts with flame graphs, fixed N+1 queries in PostgreSQL and MongoDB, and added caching with proper invalidation
    • Async data loading with infinite scroll, documented as a shared pattern for the team
    • Real-time updates through one shared PubSub, ordered so that older messages never overwrite newer ones
    • Loading skeletons, optimistic UI and type-safe URL parameters across several modules
    • End-to-end tests in Cypress
    • Elixir
    • Phoenix LiveView
    • PostgreSQL
    • MongoDB
    • JavaScript
    • Cypress

    WYDO

    App for finding sports activities and people to play with

    • Started the Android and iOS app in Kotlin Multiplatform: a map that clusters activities and loads them as you move, search and filters, groups with posts and comments, ratings and chat over WebSockets
    • Built the promo site and then moved the web version from Kotlin Multiplatform to its own React app
    • Web app with virtualized feeds, push notifications, passkey login, per-page SEO and installable PWA support
    • Four languages in the app and on the web, with tests that keep the translations in sync
    • Backend features in Spring Boot, including passkeys (WebAuthn) and translated error messages
    • Kotlin
    • Compose Multiplatform
    • Ktor
    • React
    • TypeScript
    • TanStack
    • Spring Boot
    • Vitest
    • Playwright

    CleanEEG

    Service that removes noise from EEG recordings

    • Built the web app from scratch in a team of two
    • A fast WebGL viewer that shows raw and cleaned signals over each other, side by side or as their difference, with signal filters running in the browser and full keyboard control
    • Signup, pricing, billing, notifications and a file dashboard with drag-and-drop upload
    • TanStack Router, Query, Form, Table and Virtual throughout the app
    • React
    • TypeScript
    • TanStack
    • Plotly
    • Tailwind CSS
    • Zod

    Business Data Access Point (BDAP)

    Internal dashboard for monitoring data pipelines of a large enterprise client

    • Built the frontend from reusable parts, so a new section is just a new route
    • A generic, typed data grid with nested rows, sorting and resizable columns
    • Filters, sorting and pagination kept in the URL, and a read-only mode based on user roles
    • React
    • TypeScript
    • TanStack Query
    • Zod
    • Tailwind CSS

  2. Jun 2024 to Jan 2025

    8 mos

    Švarba s.r.o.

    Full-Stack Developerremote

    A new internal system for an international direct-sales company, replacing several older PHP applications with a React web app and a new API.

    REST API

    TypeScript, Node.js and Express

    • Developed the REST API of the new system, with generated OpenAPI documentation and request validation
    • MSSQL with stored procedures, JWT login with refresh tokens and password reset by e-mail
    • Real-time notifications over WebSockets and Redis, and scheduled jobs for e-mails, imports and exports
    • Automatic translations of product texts with the OpenAI API
    • Unit and integration tests with Jest and supertest
    • TypeScript
    • Node.js
    • Express
    • MSSQL
    • Redis
    • Jest

    Web app and older system

    React, PHP and Nette

    • Forms and screens in the new React app
    • Reports, data grids and SQL in the older PHP system while it was still in use
    • React
    • PHP
    • Nette

  3. Oct 2023 to May 2024

    8 mos

    SoftPoint s.r.o.

    Junior Python DeveloperBratislava, hybrid

    Data integration and automation for a large e-commerce retailer.

    ETL pipelines

    Python and Airflow

    • Built ETL pipelines in Airflow that import products, prices and stock from more than 20 suppliers into the data warehouse
    • Sources ranged from supplier websites and APIs to XML, XLSX and FTP feeds; some needed Selenium to log in to B2B portals
    • Cleaned and matched the data with pandas, for example normalizing EAN codes and removing duplicates
    • Python
    • Airflow
    • pandas
    • Selenium
    • PostgreSQL
    • FastAPI

    Order automation

    Ruby

    • Automated ordering on 20 supplier web shops with headless-browser scripts in Ruby, a language I learned for this task
    • Ruby