Piotr Czerwiński

Work

Solo-shipped products and 9 years inside teams.

Solo-shipped products first — they're what most senior portfolios skip. Then 9 years of commercial work below — each role focused on what I actually delivered, not generic job duties. For the backstory and operating mode, read about me.

Solo-shipped products

HiddenJobs.pl

hiddenjobs.pl

AI-matched 100% remote IT roles for Polish specialists — personalized over offers from foreign companies validated for Poland-collaboration.

A live product I built solo and run as a one-person team. The core idea: senior specialists don't need more job offers — they need the right ones. Built an AI matching engine (CV analysis + natural-language preferences) over offers from foreign companies that hire Poland-remote. MVP, public job board, content engine cited by AI search within the first week of launch.

Live since Apr 202640 user accounts · 120+ on waitlistFew hundred visitors / month5k+ blog views (month 1)AI search citations < 7 days

Read the case study →

Company Docs GPT

companydocsgpt.com

Late 2023 AI experiment — Q&A over company documentation.

Built between roles in late 2023 / early 2024 — months before agent workflows became the default working mode in tech. RAG architecture over company docs with OpenAI models. Same matching/AI thesis I now build HiddenJobs on, just earlier. Live landing page + recorded demo walkthrough.

Watch demo video ↗

Online math tutoring brand and e-book product.

A small consumer-facing product I designed and shipped end-to-end on Next.js 16 + Tailwind 4 — e-book product, tutoring services, SEO-driven discovery.

Personal cycling content channel — blog + TikTok / YouTube / Instagram.

My passion project around road cycling and bikes. Blog with route reviews and gear notes, plus video content across TikTok, YouTube, and Instagram. Predates the AI-agent workflow that made HiddenJobs possible — runs on a personal cadence.

Commercial work · 9 years, foreign companies

Senior Frontend Engineer · Shiji

Mar 2024 → present

Remote · Katowice, PL

Senior frontend role inside a global hospitality tech company — high-complexity enterprise codebase. Microservices architecture; maintainer of one core frontend repository and contributor across several others. Owning release management across the full environment matrix (test, uat, preprod, prod) and every region the platform serves globally.

  • Maintainer of one core frontend repository; contributor across several others in a polyrepo setup
  • Owning release management across four environments (test, uat, preprod, prod) and every region of the global platform
  • Production incident response — diagnosing and hotfixing live PIMs (production bugs) across the global platform
  • Microservices architecture with package versioning across the codebase
  • Working with the company's design system in Storybook across product surfaces
  • AI-augmented work inside enterprise constraints — Kiro CLI (formerly Amazon Q Developer) as the approved AI co-engineer
TypeScriptReactEmber.jsRedux SagaZustandStorybook

Senior Frontend Engineer · Maandag®

Nov 2022 → Nov 2023

Remote · Amsterdam, NL

Two-sided staffing platform — employer and seeker portals, the company website, and a React Native mobile app. Built deep expertise on the company's own design system and used it across multiple internal applications, with end-to-end feature ownership on the recruitment side.

  • Built and maintained the company's own design system in Figma + Storybook, used across multiple internal applications — including making targeted changes inside those apps when needed
  • End-to-end ownership of recruitment-domain features — from spec through PO/BA/UX collaboration to release
  • Worked across two portals (employer + seeker), the company website, and a React Native mobile app
  • Code reviews and release management for the team
TypeScriptReactNext.jsReact NativeRedux ToolkitStorybookJestReact Testing Library

Senior Frontend Engineer · Assertis Ltd

Mar 2022 → Oct 2022

Remote · London, UK

UK-based online ticket retailing for train operators. Web applications across desktop, mobile and digital — direct hands-on work on Caledonian Sleeper, the overnight rail service connecting Scotland with London.

  • Direct hands-on work on Caledonian Sleeper — overnight rail ticketing across the UK
  • Worked across multiple ticketing apps in an NX monorepo
TypeScriptReactNext.jsGraphQLRedux ToolkitTailwind CSSNX monorepoJestReact Testing Library

Products worked on

Frontend Engineer · Installation Made Easy®

Jul 2021 → Feb 2022

Remote · Dawsonville, GA, USA

Direct work for Installation Made Easy® (Dawsonville, GA — Atlanta metro) — an enterprise software platform for the home improvement industry. Migrated a legacy React application to Next.js and shipped new features in close collaboration with the US-based UX/UI design team.

  • Led the React → Next.js migration on a live enterprise codebase
  • Worked directly with the client's US-based UX/UI designers across timezones
TypeScriptNext.jsReactRedux ToolkitZustandCypress

Full Stack Engineer · Shopmeister UG

Apr 2020 → Jun 2021

Remote · Berlin, DE

Solo engineering role with a direct line to the company CEO and to his clients. Greenfield plugin development from zero, plus maintenance of the existing portfolio. Built React + PHP integrations between customer Shopware 5 shops and Zalando Merchant Platform, Tradebyte, Seven Senders, and WooCommerce — across REST APIs and the FTP/SFTP + CSV exchange pattern still used by large retailers.

  • Built the Zalando zDirect Partner Connector — published in the official Shopware marketplace, lets merchants sell on Zalando from their shop with order sync, fulfilment statuses, shipment tracking, and analytics
  • Built the TB.One FTP Connector (Tradebyte Adapter) from scratch in PHP against German-only documentation — FTP/SFTP + CSV exchange covering MyToys, Mirapodo, Limango, Yomonda and other European marketplaces. The pre-REST/SOAP integration pattern Zalando and other large retailers still rely on. Published in the Shopware marketplace and used by many merchants
  • Worked across both REST APIs (zDirect, Seven Senders, WooCommerce) and the FTP/SFTP + CSV exchange pattern (Tradebyte/TB.One)
  • Solo ownership end-to-end: direct CEO contact, client requirements, scoping, delivery, maintenance
TypeScriptJavaScriptReactReact ContextExt JSMaterial-UIPHP 5/7Shopware 5Doctrine ORMMySQLJestReact Testing LibraryPHPUnit

Full Stack Engineer · secupay AG

Mar 2017 → Mar 2020

Hybrid · Pulsnitz, DE

German payment service provider. Five-person engineering team running full Scrum, with biweekly onsite trips to the company HQ in Pulsnitz (DE) for 2–3 days. Worked primarily on the e-commerce integration platform and Smart Checkout, with some work on shop-module payment plugins — full-stack across React frontend and PHP/Yii backend, processing approximately 175,000 payment transactions per day.

  • Backend handling ~175,000 payment transactions per day
  • Full-stack ownership across React frontend and PHP/Yii backend
  • Built and maintained Java, JavaScript, and PHP SDKs for merchants integrating the secupay platform — API-first design in OpenAPI/Swagger, with SDK code and docs generated from the spec
  • Biweekly onsite at the German HQ, fully embedded in the engineering team
TypeScriptJavaScriptJavaReactPHP 5Yii 1/2OpenAPIMySQLMongoDBRabbitMQPHPUnit