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Rafał Szewc · Software engineer · Gliwice, Poland (CET)

Custom software development in Poland — web, iOS and Android, built end to end

I build the backend, the web app and the native iOS and Android apps, add AI where it removes manual work, then deploy and maintain the whole thing.

You work directly with the engineer who writes the code — no agency layers, no juniors.

RS Mobile is a one-person studio. For a travel-tech client I built Turlo’s backend, web app and 2.0 iOS and Android apps, as the only engineer.

Get a quote See the work

I reply within one business hour — WhatsApp +48 517 297 217

Turlo 2.0 mobile app: the offer page of a 13-day Sicily tour with dates, duration, available spots and an Ask about this offer button
turlo.holiday — search results
turlo.holiday search results for the query Italy in October under $3000: three tours with dates, organizers and prices
Turlo: search results on the web and an offer page in the 2.0 mobile app.Turlo: an offer page in the 2.0 mobile app. Live data from turlo.holiday, Sept 2026; organizers’ photos replaced with Turlo’s destination images.

01 — Selected work

A travel marketplace in 16 languages, and software for four Polish manufacturers

I built each of them on my own. Turlo is the one you can open and try today.

Turlo logo

Client project · Travel marketplace · 2025–2026

Turlo — a commission-free trip search engine for web, iOS and Android

Organizers publish an offer by pasting a link to it. A headless browser opens their page, an OpenAI vision model reads it, and the itinerary, dates, prices and photos come back as a finished listing — translated into 15 more languages and queued for approval. Travellers contact the organizer directly; Turlo takes no commission from either side.

Search that understands a sentence

Italy in October under $3000

becomesdestination: Italydeparture: Octobermax price: $3000

A keyword search with typo tolerance finds the trips, embeddings re-rank them by meaning, and results are grouped into one card per trip.

Read the Turlo case study turlo.holiday
Turlo panel — import from links
Turlo organizer panel, Import offers from links: pasted tour URLs and the import progress list with the statuses Imported, Import failed and Importing
Importing offers from pasted links in the organizer panel. App screenshot, sample data.
languages, each with its own URLs
16
display currencies at daily central-bank rates
11
platforms: web, iOS and Android
3
Playwright end-to-end specs, plus contract tests on the frozen v1 API
26

Stack

Java 21 · Spring Boot · Angular 22 · SwiftUI · Jetpack Compose · MySQL · Elasticsearch · OpenAI · Docker

Software for manufacturing companies in Poland

Quoting, material certificates, contract production and shop-floor planning. Here is each tool in one line; its case study tells the whole story.

  • Kuźnia Polska

    Closed-die steel forgings

    A web calculator built to replace the forging-quote Excel workbook, plus a local-AI prototype that reads customer drawings.

    Angular · local LLM · EUR/PLN

    Read the case study: Kuźnia Polska

  • Mostostal Zabrze

    Engineering and construction

    A local vision model finds the EN 10204 3.1 certificate for each bill-of-materials line by heat number and saves it as a labelled PDF.

    Local vision model · Excel · PDF

    Read the case study: Mostostal Zabrze

  • Humavit

    Dietary supplements

    Contract supplement production from capsule recipe to batch, with quote margins, raw-material orders and e-invoices from KSeF.

    Recipes · KSeF · portals

    Read the case study: Humavit

  • Lakotech

    Metalwork · powder coating

    Orders tracked from a folder of DXF drawings to the delivery note, plus paint-shop orders that arrive straight from a WhatsApp group.

    DXF · WhatsApp · label printing

    Read the case study: Lakotech

02 — What I build

Web, mobile and AI, connected to what you already run

Four kinds of work, and the projects above use all of them.

  1. Web platforms

    Marketplaces, customer portals and internal panels: a Spring Boot API, an Angular front end, MySQL and Elasticsearch, deployed with Docker on your own server or in the cloud.

  2. Native iOS and Android apps

    SwiftUI on iOS and Jetpack Compose on Android, on the same API as the web app. Installed apps keep a frozen API version, guarded by contract tests, while new releases move ahead.

  3. AI features that earn their place

    Document reading, semantic search and assistants, added where they remove manual work. Cloud models when that is acceptable; local models on your own server when documents must not leave the building.

  4. Integrations

    New software has to work with what you already run. In my projects that has meant KSeF e-invoicing, Google Sheets, WhatsApp, company inboxes, network drives and label printers.

03 — How I work

A small proof first, then the full build

You see working software on your own data within weeks, before the larger budget is committed.

  1. Call

    You walk me through the idea, or the process as it runs today. I tell you what I would build first, what I would leave out, and which price band it falls into.

    Outcome

    A first step and a price band

  2. Proof of concept on real data

    A working slice of the system, built on your data. You see whether it holds up before paying for the full build.

    2–4 weeks

    PLN 10,000–25,000

    net (≈ €2,300–5,700)

  3. Staged build

    The full product or system, delivered module by module. An internal system on your company’s data usually takes two to three months.

    Internal system · 2–3 months

    PLN 40,000–120,000

    net (≈ €9,100–27,400)

  4. Maintenance

    Fixes, updates and further development after launch. Subscription billing is possible.

    Monthly

    PLN 1,000–2,000 / month

    net (≈ €230–460)

All amounts are net. The bands come from RS Mobile invoices in PLN; euro figures use the National Bank of Poland mid rate of 9 Oct 2026 (1 EUR = 4.3775 PLN), rounded. The price of a product for web, iOS and Android depends on its scope, so I name a range after the first call.

Budgets in more detail:How much does it cost to build an app in Poland? Real budgets for 2026

Rafał Szewc, software engineer
Rafał Szewc · RS Mobile, Gliwice

04 — About

Who you’ll be working with

I’m Rafał Szewc, a software engineer with more than 12 years of experience. I worked at SAP, so I know ERP systems from the inside — and when a small, focused tool will do the job better than another large system.

I run RS Mobile on my own from Gliwice, in southern Poland. I build the backend, the web front end and the native apps myself, and I’m the person who answers your messages.

Experience
12+ years, including SAP
Based in
Gliwice, Poland
Time zone
CET — the same working day as Berlin, Amsterdam and Stockholm, one hour ahead of London
Languages
English, Polish
Backend and web
Java 21, Spring Boot, Angular 22, MySQL, Elasticsearch
Mobile
iOS (SwiftUI), Android (Jetpack Compose)
AI
OpenAI APIs; local models through Ollama (Qwen, Bielik)
More about me LinkedIn profile

05 — From the blog

Guides for people planning an app

Written from my own builds; each guide shows the date it was last updated.

All posts

  1. Best countries for app development in 2026, and when Poland is the wrong choice

    Rates, time zones, EU law and delivery risk compared side by side, including cases where another country fits better.

    Updated

  2. Best mobile app development in Poland: agency, freelancer or senior studio?

    Agency, freelancer or a senior one-person studio: red flags, questions to ask, and what each option costs.

    Updated

  3. iOS app development services in Poland: costs, process and App Store review

    SwiftUI in practice on Turlo’s iOS app, what App Store review checks, and what an iOS build costs.

    Updated

  4. Mobile app development trends 2026: notes from building a 16-language app

    What building Turlo 2.0 taught me: native SwiftUI and Compose, LLM features inside the product, and one set of strings for 16 languages.

    Updated

  5. How much does it cost to build an app in Poland? Real budgets for 2026

    Budgets from my own builds, dated hourly rates, and an MVP compared with a full product in EUR and PLN.

    Updated

06 — FAQ

Questions people ask before we start

How much does custom software development cost?

A proof of concept on your data costs PLN 10,000–25,000 net (≈ €2,300–5,700) and takes 2–4 weeks. An internal system built on your company’s data is usually PLN 40,000–120,000 net (≈ €9,100–27,400) over 2–3 months, and maintenance is PLN 1,000–2,000 net (≈ €230–460) a month. For a product on web, iOS and Android, I name a specific range after one call about scope. Euro amounts use the NBP mid rate of 9 Oct 2026.

How do time zones and communication work?

I work on Central European Time, in English. That is the same working day as Berlin, Amsterdam and Stockholm, one hour ahead of London, and my afternoons overlap with US East Coast mornings. You hear from me directly, on calls and in writing, and I reply on WhatsApp within one business hour.

Who owns the code? Will you sign an NDA?

Code ownership, confidentiality and handover are agreed in the contract before any work starts. If your company has its own NDA template, bring it to the first call.

What tech stack do you use?

Java 21 and Spring Boot on the backend, Angular 22 on the web, SwiftUI on iOS and Jetpack Compose on Android. Data sits in MySQL, search runs on Elasticsearch, and everything ships in Docker. For AI I use OpenAI models where cloud processing is acceptable, and local models through Ollama (Qwen, Bielik) on your own server when documents must stay in-house.

You’re a one-person studio. What if you’re unavailable?

Your project doesn’t live only in my head. The code can sit in your own repository from the first commit, each project has written setup and deployment notes, and it is built with mainstream tools — Java, Angular, Swift, Kotlin — that an experienced developer can pick up. How a handover to your next developer works is set out in the contract before we start.

07 — Contact

Tell me what you want to build

A few sentences are enough. I’ll reply with questions, or with a suggestion for the first step.

I use these details only to reply to your enquiry.

WhatsApp