You 🤝 Przemysław? Senior full-stack engineer for hire

I don’t know who you are. I don’t know what you need. But I have a very particular set of skills, acquired over a very long career. Fifteen years of it.

TypeScript, React, Node.js, Cloudflare, Postgres, PostHog. AI coding agents under rules I write and tests I enforce. Available from November 2026, B2B or employment, Wrocław or remote.

Book a free 30-min call Email me instead

Three question marks in the sky. One phone number at the bottom.

When you get a call for an interview but you have applied to hundreds of jobs. Clip: Taken (2008), as circulated on X and Instagram. Not my footage.

15+ years shipping softwarenine of them in TypeScript, React and Node.js
React since 2017in production, every project since
~30% of merged PRs opened by an agentin 2026, under my rules, ~85% reviewed by me
CASA Tier 2 and WCAG 2.2 AAas automated gates on every pull request

Riddle me this

Interrogation room

Five questions. Riddler asks, you answer. You get a case file matched to you, not a brochure.

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The numbers don’t lie. The Riddler does.

15+years shipping software

2017React in production since

~30%of merged PRs in 2026 opened by an AI agent, ~85% reviewed by me

800+pull requests reviewed on one product, 2018 to 2026

Riddle me this

Ten riddles. Every answer is a number or a product from my career. Score at the end. The last riddle is yours.

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The Riddle. Unsolved since 1984.

Your roadmap does not have to be. Press play, then keep scrolling. The video follows you.

Read on while it plays

Case files

Closed cases. Names only where I am allowed to use them. Open any folder.

Patriot Mail: from first commit to the App Store in four months

The problem: A greenfield AI-native email client for web, iOS and macOS had to reach real users fast, pass Google’s CASA Tier 2 security assessment and work for older people.
What I did: I was the principal engineer. I wrote the delivery plan, shaped the product vision and treated prompt injection through untrusted email as a design constraint before any model touched a mailbox. CASA and OWASP ASVS controls became a Playwright suite that runs on every pull request. WCAG 2.2 AA sits behind an automated axe gate.
Result: Public App Store release in four months. CASA Tier 2 passed and the yearly questionnaire turned into a check on every PR. Text scaling to 200% and a calm-email mode shipped for older users.

4 months CASA Tier 2 WCAG 2.2 AA Open ↗

See also: SaaS & MVP · Mobile & desktop apps

An AI coding agent as a team member, under enforced rules

The problem: Coding agents produce ten times the output and ten times the mess. A team of four wanted the speed without a slop swamp on main.
What I did: I authored the rule set shared by Claude Code and Codex: mechanical checks over written rules, lint and test gates for security, API surface and CSP, agents working on main with hooks, every PR reviewed by a human, AI-assisted content disclosed as such.
Result: In 2026 the agent opened about 30% of merged pull requests across two products and I reviewed about 85% of them. My own output went from under 1,000 to 5,000+ commits a year.

~30% PRs by agent ~85% reviewed 5,000+ commits/yr

Sandtime.io: founding engineer, eight platforms, one codebase

The problem: A time-tracking SaaS had to live where people work: desktop tray, browser, phone and app stores.
What I did: I authored the original product vision and architecture in 2018 and made the first commit. React Native wrappers for iOS and Android, Electron for macOS, Windows and Linux, a Chrome extension, multi-tenant routing, SSO, Dockerized services, Paddle and Mac App Store subscriptions, CI/CD.
Result: Eight platforms shipped and run in production. The only engineer active in every year of the product, 8,000+ commits and close to half of all merges to trunk.

8 platforms 8,000+ commits since 2018 Open ↗

See also: Mobile & desktop apps · SaaS & MVP

Suppression-list platform: MVP to product, 300+ GB in production

The problem: A UK email publisher needed suppression lists built to grow to terabyte scale with constant-time sign-up and zero-downtime deploys.
What I did: I led a team of three engineers and a QA from MVP to the full platform. Postgres partitioning by tenant and list, parallel request pipelines, blue/green deploys. One-click unsubscribe shipped four months before Google and Yahoo announced the requirement.
Result: 300+ GB and millions of events in production, zero-downtime deploys, and a compliance feature that landed before the deadline existed.

300+ GB team of 3 blue/green

My own chat app: 30,000 concurrent users on sharded .NET servers

The problem: An ad-supported anonymous chat grew faster than one server could carry, and nobody else was going to run it.
What I did: Horizontally scaled, sharded C# and .NET servers, my own chat network, a moderation panel, automated NSFW detection, support answered by me.
Result: 30,000 concurrent users, 1.5 million+ downloads and 37,000+ ratings across 21 national stores (4.5 average in the US). It paid my bills for five years and ended when Windows Phone did.

30,000 concurrent 1.5M+ downloads 5 years

Sources: Promegle, US store 2015: 17,378 ratings

See also: C# & .NET (legacy) · SaaS & MVP

Korona Krulów: a satirical React game for 100,000+ players, built in two weeks

The problem: Spring 2020, lockdown, a joke that deserved a game before the joke got old.
What I did: React, 400+ actions, a leaderboard, open source on GitHub, shipped in two weeks of evenings.
Result: 100,000+ players and ~700 upvotes on Wykop at launch.

100,000+ players 2 weeks open source Open ↗

Sources: Wykop: 698 upvotes · Antyradio · Wieści24 · Code on GitHub

Why so serious? Because the pipeline is red.

Five habits, one deck of cards. Pick one up.

Agents under rules

Claude Code and Codex work on main with hooks, lint and test gates. The model suggests, the criteria decide. Every PR gets a human review and AI-assisted content is disclosed.

Zero bug policy

A bug is fixed or consciously closed, never parked. Alerts and error tracking in every project, so I learn about problems before the client does.

Review as a craft

Hundreds of pull requests reviewed. I review for the product and its reasons. The code comes second.

Measured, not assumed

PostHog in every project from day one. A tracking plan per feature and dashboards leadership actually reads.

No product manager? Fine.

Where there is no PM I set priorities directly with the people using the software and answer support myself.

Press

Written up elsewhere

Real links, from Windows Phone apps in 2012 to a game in 2020. Online I go by Ciunkos. Some outlets are gone, so those links open an archived copy.

Antyweb AwardMar 25, 2013“Jury wybrało najlepsze aplikacje w konkursie AppAward”AppAward 2013: Pogaduszki won the Other category on Windows Phone, out of 300 apps entered across iOS, Android and Windows Phone.Read Microsoft PolskaSep 2, 2012“Najlepsze polskie aplikacje na Windows Phone”Microsoft Poland’s hand-picked list of the best Polish Windows Phone apps featured my Kwejk app (archived copy from September 2012).Read the archived copy wp7.com.plApr 7, 2012“Więcej o aplikacji Gadu”A chat with me about Gadu: “for that period Gadu was the most downloaded app on the Polish Marketplace.”Read AntyradioMay 4, 2020“Zawalcz z epidemią jako rząd i zdobądź Koronę Krulów. Prześmiewcza gra z paskami TVP”“The work of one programmer, who built it literally at night.” Antyradio’s review of the game.Read the archived copy Gazeta PlusMay 2, 2020“Gra »Korona Krulów«. Stań na czele rządu PiS i podejmuj decyzje w czasach zarazy…”News piece on the game, the day after launch.Read the archived copy Wieści24May 2, 2020“…W sieci pojawiła się gra o koronawirusie w Polsce: Korona Krulów”News coverage of the game the day after launch.Read

More mentions (9)

WykopMay 1, 2020“Poczuj się jak Prezes i pokieruj państwem w Koronie Krulów - gra już dostępna”Korona Krulów launch day: 698 upvotes and 152 comments.Read OnMSFTJan 11, 2013“Windows Store app highlight: Windows Phone Store, grab the latest Windows Phone apps via Windows 8”My Windows 8 app for browsing the Windows Phone Store, featured as a highlight.Read windows-phone.plJan 11, 2013“Aplikacja »Windows Phone Store« dla Windows 8”“Built by Ciunkos, known for apps like Pogaduszki and Memgenerator.”Read the archived copy appsblog.plSep 26, 2012“Memgenerator – stwórz śmieszny obrazek na telefonie”Review of Memgenerator, my Windows Phone meme maker.Read KomórkomaniaMay 12, 2012“Pogaduszki - klient sieci Gadu-Gadu dla Windows Phone'a”Review of Pogaduszki, my Gadu-Gadu messenger: 4.5 stars from 68 ratings at the time.Read Telix.plMay 11, 2012“Pogaduszki: nowy klient GG na Windows Phone”Launch of Pogaduszki for Windows Phone 7.5: free, no ads, push through my own server.Read wp7.com.plMay 5, 2012“Nieoficjalny klient GG – »Pogaduszki« juz dostępny”Pogaduszki ready “after many hours of work and testing”, no splash screen so it starts faster.Read windows-phone.plMay 2, 2012“Pogaduszki czyli nowy klient GG!”After my first Gadu-Gadu app was pulled over a copyright claim, I rebuilt it as Pogaduszki without the infringing parts.Read the archived copy GaduNewsApr 30, 2012“GG Network usuwa nieoficjalny komunikator na Windows Phone”Gadu, the first native Gadu-Gadu client on Windows Phone 7, comes down after a trademark claim. Quotes my statement.Read the archived copy

Interrogation room

An agent on this page answers for me. It only knows what is on this site and says so when it does not. Limited per visitor and by a daily cost cap. Nothing you type is stored.

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Before you book

Riddle me this: what is cheap, fast and never says “you’re absolutely right”?

Not me on the first two. Me on the third. Scope first, then a number in writing. The call is free either way.

Our core language is named after a snake, an island or a coffee.

Then I am the wrong person and I say so now. TypeScript, React, Node.js and Cloudflare are what I sell. C# and .NET for ten years before that.

When can you start?

November 2026. B2B or employment. Solo, or leading a team of up to four.

Remote?

Wrocław or remote. Nine years with US, UK and EU teams, across a nine-hour time difference when needed.

Will you work with our coding agents?

Yes, under rules. Lint and test gates, review on every pull request, AI-assisted content disclosed. In 2026 an agent opened about 30% of merged PRs on two products and I reviewed about 85% of them.

Why the Batman thing?

Because every “senior full-stack engineer” page looks the same. This one you will remember. The page itself is the work sample: static HTML, no framework, a CSP without inline scripts, axe in CI. View source.

One foot in the door

Not ready for a project? Start smaller.

Two ways to see how I work before you commit to a sprint. Fixed scope, a number in writing after a short call.

Codebase audit, one week

I read the repo, CI, tests, security and the parts the team avoids. You get a written report with findings ranked by risk, a plan with milestones and a go or no-go you can defend. I have run this for a large software house before its clients saw the code.