Software that solves the problem, not just looks good.

I design and build websites, web and mobile apps, automations and AI features — from the first conversation about the problem to a working product in production.

Let's Talk About Your Project See Projects

Web · Mobile · AI · Automations

One person accountable for the entire product

Status

Deployed

What I Do

Five ways to move your business forward.

01

Websites and online stores

A site that sells, not just looks good — fast, built for SEO and ready for traffic. Stores with payments, customer accounts and a back-end you can manage yourself.

Online stores · Business sites · CMS

02

Web applications

Customer portals, dashboards and internal tools that replace spreadsheets and email attachments — one place where your team actually works.

Panels and dashboards · Internal systems · Client portals

03

Mobile applications

One codebase, two platforms. Mobile apps built in Flutter, ready to publish on the App Store and Google Play, with a backend that handles real traffic.

iOS and Android · Flutter · Production apps

04

AI and automation

I take over repetitive work: process automations, system integrations and AI-powered features — from document classification to customer-facing assistants.

Automations · LLM integrations · Document processing

05

Custom software

When off-the-shelf tools stop being enough: systems tailored to a specific business process and integrations that connect existing software into one whole.

Custom software · API integrations · System migrations

Flagship project

0blunders

A complete training platform for chess players, designed and built from scratch as a fully working product — not a prototype.

Mobile app, a backend handling payments and subscriptions, a chess position analysis engine, AI features, game import from handwritten notation via OCR, and a statistics panel — all running on infrastructure designed for real-world scale.

Flutter FastAPI Stripe Analysis engine OCR AI
Chess game analysis in the 0blunders app Chess puzzle module in the 0blunders app

Product

Mobile app for iOS and Android, game and opponent database, training dashboard.

Infrastructure

Backend and server processing designed for scaling and background analysis.

Monetisation

Payments and subscriptions implemented via Stripe, full billing lifecycle.

AI

Automatic position analysis, blunder detection and OCR for importing games from photos.

Other projects

Selected work.

CRM panel for a solar installation company

Problem: enquiries and installation statuses scattered across emails and spreadsheets — no overview of the whole pipeline.

Solution: a panel with a single client view, automatic task assignment and deadline notifications.

Result: the team sees the status of every installation without asking about it on Slack.

Online store with recurring orders

Problem: orders taken by phone; no sales outside business hours.

Solution: an online store with payments and subscriptions for regular deliveries.

Result: orders come in automatically, around the clock, without a phone call.

Delivery schedule automation

Problem: routes planned manually each morning — frequent errors and driver downtime.

Solution: a tool that builds routes automatically from the day's orders.

Result: route planning takes minutes, not an hour every morning.

Why a small studio

Less bureaucracy. More work done.

GM Coding is a one-person studio run by Paweł Rzeszotarski. No layers in between — every project passes directly through the hands of the person building it.

Direct contact with the developer

You talk to me, not a project manager relaying your feedback further down the chain.

Fast decisions and fast deployments

A scope or priority change happens immediately — no three-level approval process.

Modern stack, chosen for the problem

Technology is a means to an end, not a procedure to follow.

Business-first, not just technical

Before I write a line of code, I understand what needs to change in your company.

Accountability for the whole product

From idea, through design and code, to production deployment and ongoing support.

How I Work

You don't need to come with a ready specification.

A business problem or a raw idea is enough — everything else, from scope to architecture, we figure out together.

01

Discovery

We talk about the problem, the business goal and the real constraints.

02

Design

I define the scope, architecture and key screen wireframes.

03

Development

I build the product in short iterations with regular checkpoints.

04

Launch

Production deployment, testing and polish before go-live.

05

Growth & Support

Maintenance, new features and support after launch.

Tech Stack

I choose technology to fit the problem, not the other way around.

Flutter Python FastAPI PHP TypeScript SQL AI / LLM Cloud / VPS API Stripe

Have an idea or problem to solve?

Let's see what we can build. Write a few words about your company and what you want to change — I reply personally.

contact@gmcoding.com +48 ··· ··· ···