Philosophy Who it's for How we work Case studies About us Blog Services Tell us your idea PL
Less clicking. More time to grow your business.

Custom apps for business.

We design and build web applications, internal systems and automations tailored to the way your company works. The code, data and rights to the project belong to you from day one.

2-6 weeksfirst version ready to test
48 hoursinitial analysis and quote
100%the code and data belong to you
Case studies from real life →
Custom CRM

From Excel to a custom CRM

Contact timeline, pipeline, PDF report and a management board instead of seven spreadsheet tabs.

View case study →
Location analysis

localscope.pl - premises before you lease

5/10/15-min reach zones, competition on the map and a 0-100 potential score with a PDF report.

View case study →
Technical calculator

Busbar current calculator

Copper and aluminium busbar sizing in a fraction of a second - no consultation, used daily.

View case study →
3D map + narrator

Wrocław 3D with a virtual tour

A photorealistic 3D map with 12 landmarks and a cloned narrator voice - built in one weekend.

View case study →
POS platform

Field stall sales

A tablet app and manager dashboard instead of reconciling cash and stock on paper.

View case study →
Case studies

We show systems that people use every single day.

From POS apps, through custom CRMs and technical calculators, all the way to tools powered by artificial intelligence. Every project was built to solve a specific business problem. Not to look good in a presentation.

1 / 5
Digital POS platform

A seasonal fruit seller with a network of field outlets.

The challenge

Reconciling takings and stock at the stands was done traditionally on paper. There was no quick insight into inventory levels and takings during the working day.

The solution

A lightweight, responsive tablet app for sellers, connected to a central database. The owner received a clear management dashboard accessible from a smartphone.

The result

Complete elimination of manual after-hours reconciliation of takings. The time needed to add a new point of sale cut to 60 seconds.

Read the case study
1 dashboardinstead of a series of calls and notes every day
Livereal-time view of inventory levels

"Working on unified, real-time data let us save more than a dozen hours a week on morning delivery logistics alone."

Interactive engineering calculator

KUVER GmbH - manufacturer of flexible high-current connections, Berlin.

The challenge

Electricians and installation designers had to manually match busbars to project specifications. Every product enquiry required a separate technical consultation - slowing down sales and tying up the company's engineering team.

The solution

An online calculator that computes the maximum current-carrying capacity of copper and aluminium busbars. The user enters dimensions and thermal parameters and instantly receives cross-section, heat losses, resistance, and maximum current - no login, no consultation needed.

The result

The tool became a daily reference for electricians and designers across Europe. Regular return visits build brand trust and directly drive purchase conversions for KUVER products.

Read the case study
< 1stime to match a product to specification requirements
Dailyused by professionals as a working tool, not just a sales page

"Instead of answering the same product-matching emails over and over - we gave engineers a tool. They come back on their own and place the order themselves."

3D map with a voice guide

Wrocław 3D - a photorealistic city map with a virtual tour.

Challenge

An exercise project: see how much can be built in a single weekend in a duo with AI. An interactive 3D map of Wrocław with twelve landmarks and a tour that guides you through the city on its own - no framework, no backend.

Solution

Google's photorealistic 3D tiles with a MapLibre vector fallback, a camera orbiting the landmarks, and a narrator - the voice of a C3S co-founder cloned in ElevenLabs. The whole thing tested automatically with Playwright.

Result

A working site, wro3d.pl, with twelve audio narrations and zero running costs. Production-grade lessons: API fallbacks, cost caps and tests that caught bugs invisible to ordinary clicking.

Read the case study
1 weekendfrom idea to a working site with a tour and narrator
€0running costs - static hosting and Google's free tiers

"A cloned narrator's voice and photorealistic 3D raised the bar of what can be done in a weekend by several levels."

Location potential analysis

localscope.pl - check the location before you sign the lease.

Challenge

Choosing premises is one of the most expensive decisions when opening a brick-and-mortar business. A lease binds you for years, and gut feelings like "there's decent footfall here" can cost a fortune - hard data about the area is rarely checked.

Solution

A free tool that draws zones of actual walking or driving reach in 5, 10 and 15 minutes for any address, counts the residents, pins the competition on the map and factors in the area's affluence and footfall generators.

Result

A working tool, localscope.pl: a transparent 0-100 potential score with weights you set yourself, and a PDF report ready for a business plan or a loan application.

Read the case study
0–100a transparent potential score broken into components
60 sfrom clicking a point on the map to a full report

"Nobody walks in a straight line - a river or a dual carriageway can cut off half a neighbourhood. Real reach only shows on the street grid."

Custom CRM (Excel → app)

A Key Account Manager at an industrial manufacturer - the end of working in Excel.

Challenge

The entire client workload lived in a single Excel file with seven tabs: contact history in one text field, manually calculated totals, inconsistent dates and a real risk of overwriting all the work with a single click.

Solution

A custom CRM web app mirroring the KAM's process: an interaction timeline, a kanban pipeline, orders with overdue payments, an automatic PDF report and a separate board for management - fully in the client's visual identity.

Result

One source of truth instead of seven tabs, zero manual summing and a full history of every client contact. 100% of the existing data migrated from the spreadsheet.

Read the case study
1 sourceone consistent database instead of seven Excel tabs
PDF reporta weekly summary generated automatically

"The CRM app looks great, brilliant automation and simplification, genuinely superb. The manual is clear and helpful too. Thanks so much!!"

Our approach

First we learn the process. Only then do we build the app.

Every company works differently. That's why we don't sell ready-made templates or try to force your business to fit an existing program.

First we talk about how your team works. We look for the places where time is lost, errors appear or the same actions keep repeating. Only then do we design a tool that solves a specific problem. Our goal is to give your people less work and make the company run more smoothly.

Clever - smart simplification of processes Code - clean, easily scalable code Craft - craftsman-grade attention to every detail
Areas of expertise

We build systems tailored to the way your company works.

We start by deeply understanding what your working day looks like - and only then do we move on to writing code.

Retail and sales

Got an online store, ERP, warehouse and Excel? We connect them into one coherent process. No more re-typing data by hand.

What we build Sales systems, POS apps, warehouse integrations, order automation and loyalty programs.

Medicine

Systems for practices and clinics. Patient registration, medical records, questionnaires, appointment management and secure data processing in line with GDPR.

Compliance and standards Patient data encrypted at the database level, EU hosting and full compliance with GDPR built into the system architecture.

Services

We build tools for handling orders, bookings, fieldwork and process management. Instead of several different tools you get one coherent system.

A real business problem Replacing five separate SaaS subscriptions with one coherent system that perfectly reflects your company's unique procedures.
How we work

Four steps from idea to a finished app.

No unnecessary technical jargon. At every stage you have full transparency over the budget and the progress of work.

01 / CONVERSATION

Conversation

We get to know your business and together define the problem to solve.

02 / ANALYSIS

Analysis and design

We prepare the concept and a fixed quote. You know how much you'll pay and what you'll get.

03 / PROTOTYPE

First version

Within a few weeks you get working software that you can test in your own company.

04 / GROWTH

Growth

After deployment we grow the system together with you.

Scope of work

How can we help? We don't sell ready-made packages.

Every company has different processes. So instead of off-the-shelf bundles we propose solutions designed around the way you work.

Most often we build:
  • custom web applications
  • CRM and ERP systems
  • B2B portals
  • apps for employees
  • process automations
  • integrations with existing systems
  • AI-powered solutions
Let's talk about your project
Why C3S

We don't lock our clients in.

Once the project is complete, you receive:

  • ✔ the full source code
  • ✔ the database
  • ✔ the copyright
  • ✔ the documentation
  • ✔ the freedom to keep developing with any team

For us that's standard. For many software houses it still isn't.

1:1Direct contact with the engineer leading your project
EUGDPR-compliant architecture, hosting in secure data centers in Europe
0 złA free 30-minute consultation meeting and quote
100%Ownership of the code and databases after the system is deployed
Meet the founders

Does your team do the same work every day? Let's automate it.

You talk to the people who will build your system. From the very first conversation you deal directly with the people responsible for the solution's architecture and technical decisions. No middlemen. No passing information between departments. That shortens the process and lets you make decisions faster.

Przemyslaw Czujowski - Co-founder of C3S

Przemyslaw Czujowski

System architecture and security

He combines nearly 30 years of experience leading complex projects (Pre-Sales, KAM) with advanced engineering and analytical expertise. At C3S he is responsible for solution architecture, the quality of delivered code and rigorous data security. As a lecturer and AI practitioner, he designs systems with a focus on scalability and digital resilience. He ensures the technologies deployed guarantee continuity of operations and stable growth for your business, with no architectural compromises.

Romuald Karkoszka - Co-founder of C3S

Romuald Karkoszka

Strategy and business processes

Drawing on 25 years of experience in sales, marketing and product management, he effectively translates business goals into precise technology requirements. At C3S he is responsible for pre-implementation analysis and the visual design of every system. His approach is fully technology-agnostic – he matches tools and architecture strictly to your company's budget and operational processes, favouring pragmatism and cost optimisation over passing trends.

FAQ

Frequently asked questions.

How does the copyright transfer process work?

Along with the settlement of the final stage of work, we transfer the full economic copyright to all the source code written. You receive access to the code repository and the complete database. We do not apply any licenses that limit the number of users or workstations.

Is medical software fully secure?

Yes. When designing solutions for medical facilities, we implement advanced security procedures: encryption of databases at rest, two-factor authentication (2FA), full logging of user activity and hosting in a cloud that meets GDPR requirements for sensitive data.

What does support look like after the application goes live?

Every project includes free post-deployment support (warranty and technical assistance) for a period of 14 to 30 days. For larger, more complex systems, we can sign an ongoing service agreement (SLA) with a guaranteed response time to requests.

What if my requirements change during the project?

A deployment based on a prototype (Alpha) version is designed precisely to catch such changes at an early stage. If during the work you decide to add a new feature, we will quote it as a separate extension on clear financial terms, without halting work on the main version.

Knowledge base

Before you order an application - see how it works.

Concrete information about the costs, process and technologies of custom software. No jargon and no marketing fluff.

Get in touch

Got an idea for a system?

Let's talk. The first consultation is free. After the call you'll get an initial concept and a rough project quote. In a short conversation we'll check whether custom software is the best solution and prepare an initial quote.