Przejdź do treści głównej

Web & App Development

We Build Websites & Apps – And Make Them Scale

We turn ideas and designs into fast, reliable websites and apps — built with the right technology for the job, custom code or no-code, and maintained long after launch.

KARTS 5 apps development
Clutch Dark
Karts design 50 pros dark

Our Services in Web & App Development

We Design & Build:

Custom Apps & SaaS

  • Web Apps

  • Mobile Apps

  • SaaS

  • Online Platforms & Portals

KARTS portfolio

Websites

  • WordPress

  • Custom Code

  • No-Code

KARTS portfolio

E-commerce

  • Online Stores

  • Product pages

  • Checkout

KARTS portfolio

Integrations & AI

  • CRM / ERP

  • APIs

  • AI & Automation

KARTS portfolio

Why Karts

A High-Quality Design Built Around Your Business

Design & Dev 
in one team

We build what we design, so nothing gets lost in handoff.

Modern Visual Design

Clean, contemporary visuals that attract attention, build credibility, and strengthen your brand’s professional image.

005 scale
Built to scale

Architecture that holds up as your traffic and data grow.

027 pros and cons
Easy-to-Manage CMS

An intuitive content management system that lets you update your app easily — without relying on developers.

Performance & Optimization

Fast-loading, optimized apps built with performance, stability, and scalability in mind.

Custom Functionality

Tailored features and integrations designed to match how your business actually works.

Ongoing Support

We provide ongoing support, updates, and improvements to keep your website reliable and up to date.

Fast Project Kickoff

Launch your project quickly with a clear process and efficient implementation.

Process

How We Deliver Results

Group
Scope & Architecture

 

We agree on goals, requirements and the right tech, then plan a structure that handles real data, traffic and growth — all before any code.

Build

 

We develop in short sprints, so you see working progress, not just status updates.

Test & QA

 

We check performance, security and every device before anything goes live.

Launch & Support

 

We release it, watch it, and keep improving it after go-live.

Trusted by

ZDROVENO logo R DESKTOP TBH2NTK
PROMAILING logo
QUICKSORT logo black
PRESPECTO logo
Noble Values Logo
KAASS logo
HAPPYME logo blue copy
ESRI POLSKA logo czarne
Alchem logotype web
EVER logo green
Kopenik data
KENO primary logo primary WEBSITE
WORD BIELSKO logo
Logo napis
RUBY Europe
BioTectum logo red Distributor Platform DARK
Logotyp do gotowe
URS logotype
Frankensolar logo
Property 1=Czarne niebieskie
D4S logo black
ARTIS Mateusz Matuszyk logo
Romania Express logo 2023 Green
SOLPURE sample logo
Marketing technology LOGO
ZUMA logo — Real World Assets 500px
Logo Audiofon z niebieską
Verdehire logo green
QMP MIESO
MEINESCHULTUETEN logo alle
Profilowe Fundacja
Weles3.pl logo
149 ZUMA logo copy
GRA DLA PARY logo black
Logo silv1

Top-Tier Applications  for Your Business

We create effective digital products — from UX/UI and design to development and launch. Websites and online stores built for companies that want to operate professionally and grow faster.

KARTS people clients happy

One partner, from first idea to launch

We work as an extension of your team — turning ideas into digital products that perform, with clear stages and full ownership from design to launch

  • Design and development in one team
  • Decisions backed by user testing
  • One partner for your whole product
  • Reliable, Long-Term Collaboration

WHAT OUR CLIENTS SAY

The proof is in the partnership

Website, IT & Content For The World’s Leading Geolocation Systems Provider

Website, IT & Content For The World’s Leading Geolocation Systems Provider

,,I hereby confirm that Karts Design has provided us with a service consisting in the design and implementation of a new, expanded version of the esri.pl website. The project included dozens of subpages, numerous functionalities, content modules, and solutions supporting our key business processes.
The implementation process was smooth and orderly, and all stages – from planning, through design, to the launch of the website – were carried out with great attention to technical quality and usability. We also appreciate the open communication and willingness to respond to changes and challenges that arose during the work.
Karts Design also supported us in creating a dedicated website for the GIS Congress event, providing comprehensive services – from UX/UI concept to implementation.
We also cooperate on the ongoing development of the esri.pl website – introducing new functionalities, integrations, and creating dedicated tools to support the operation of our website.
We value Karts Design for its flexibility, timeliness, and efficient and cooperative communication. We recommend this company to organizations looking for a committed and trustworthy digital partner.,,

Urszula Niedbałko Urszula Niedbałko Marketing Manager – Esri Polska
View Project
UX/UI & Graphic Design For A Leading Software House

UX/UI & Graphic Design For A Leading Software House

,,Before we started working with KartsDesign, every graphic design or UX/UI project caused a lot of frustration. We constantly had to wait for available graphic designers and discuss details with someone other than the person actually doing the project—even for the simplest tasks, such as a poster for social media.
Now, the whole process is extremely simple—I post my request on Slack or Figma, and the next day I have ready-made graphic designs. There is always one that perfectly meets my expectations. The work is done quickly, efficiently, and without any unnecessary involvement on my part. KartsDesign is a partner that is truly committed to its work – it works quickly while maintaining very high quality. Working with them is a pure pleasure.,,

Mariusz Kozieł Mariusz Kozieł CEO – VISUALITY
View Project
Website for a Government Examination Institution

Website for a Government Examination Institution

,,I fully and confidently recommend Karts Design, the company responsible for the implementation of the website www.word.bielsko.pl. The cooperation ran very smoothly at every stage of the project – from initial arrangements, through graphic design, to implementation and launch of the website. The team demonstrated a high level of professionalism, punctuality, and openness to the client’s needs and suggestions.
The website was created with great attention to aesthetics, functionality, and user convenience. The service is modern, clear, and intuitive to use on both desktop and mobile devices. All key features work flawlessly, and the proposed technical and visual solutions have genuinely improved communication with the audience.
Particular recognition is due for the excellent contact with the contractor, fast response to feedback, and strong commitment to refining every detail. Karts Design is a reliable and trustworthy partner for delivering web projects.,,

Piotr Milewski Piotr Milewski Head of the IT Department – WORD BIELSKO
View Project
Website & Marketing For A Leading Energy Solutions Provider

Website & Marketing For A Leading Energy Solutions Provider

,,We had the pleasure of working with the agency on the new version of the website www.keno-energy.com and we can wholeheartedly recommend them as a trustworthy partner. The project was carried out in an exemplary manner at every stage – from needs analysis, through graphic design and development, to launch and post-implementation support.
We would like to particularly emphasize the professionalism, commitment, and excellent communication of the entire team, especially the project manager Kajetan, who demonstrated excellent organization, substantive support, and great attention to detail. Thanks to his work and the competence of the team, the end result met our expectations not only in terms of visuals, but above all in terms of functionality and business.
We fully recommend working with this agency to any company looking for a professional partner in the field of website design and development.,,

Karolina Kalinowska Karolina Kalinowska Marketing Director – KENO
View Project
Website & Social Media For An Animal Welfare Foundation

Website & Social Media For An Animal Welfare Foundation

,,Karts Design’s implementation of our website was exemplary. We appreciate their high level of professionalism, commitment, and the fact that they selflessly went beyond the agreed scope of work to ensure that the project fully supported our mission. We are extremely grateful for this support, which will make it much easier for the Foundation to find new homes for our charges.,,

Joanna Copik Joanna Copik Founder- Fundacja Pomagamy Kotom By Znalazły Dom
View Project
Websites, Apps & Branding For Various Brands Of A Tech-Industrial Company

Websites, Apps & Branding For Various Brands Of A Tech-Industrial Company

,,We have had the pleasure of working with Karts Design for two years, where our cooperation has mainly focused on website development, leaflet design, and building our company’s image through social media marketing in the field of medical chemistry. All projects commissioned to Karts Design were carried out with the utmost care for quality, demonstrated creativity, and were completed in line with our expectations. We value the professionalism and commitment of the Karts Design team, which translates into more and more new orders, which we hope will continue to confirm their professionalism, creativity, and commitment to their work. We recommend Karts Design as a partner for projects in the broadly understood field of marketing, because in our opinion, their activities enable the building of a solid foundation for success in the field of image creation and marketing strategy.,,

Krzysztof Solich Krzysztof Solich Production Director – ALCHEM Group
Website, E-Commerce, Marketing & AI Automation For An Innovative Startup

Website, E-Commerce, Marketing & AI Automation For An Innovative Startup

,,I have been working with Karts Design for a long time on projects for Green Lungs and WallEver, and from the very beginning it has been a very specific and well-organized collaboration. Communication is efficient, topics are clearly defined and implemented on time, without unnecessary complications. The team does not limit itself to simply fulfilling orders, but is genuinely involved in projects and thinks about them from a business perspective. They often propose their own solutions or improvements that really enhance the final result.
We are also currently starting a large mobile game project, which is a natural step for me after our previous collaboration and a confirmation of my trust in the Karts Design team. I can recommend them with a clear conscience as a reliable, committed, and professional partner.
,,

Daniel Szewera Daniel Szewera CEO & Founder- GREEN LUNGS
View Project
Branding, Websites & Marketing For An Innovative Startup

Branding, Websites & Marketing For An Innovative Startup

,,We have been working with Kajetan and the KartsDesign team for over a year. They have created two websites for us, and we commission them to prepare all graphic materials and run our social media. What we value most in our cooperation is their responsiveness. It often happens that we need something right away, and every time the response is immediate. We have not had any conflicts so far. We recommend KartsDesign to our business friends, and to my knowledge, they are also satisfied. I can therefore confidently recommend KartsDesign as a contractor who listens (which is not common today), responds, and cares about the quality of their work.,,

Marek Lesz Marek Lesz CEO – ZUMA
View Project

Free UX/UI Audit for Your Website or App

Discover what hurts your conversion rate. We will analyze your platform, spot usability flaws, and show you practical fixes.

FAQ

Frequently Asked Questions

document.addEventListener('DOMContentLoaded', function() { // Mapowanie przycisków do odpowiednich sekcji FAQconst categoryMap = { 'ogolne': '#ogolne_faq', 'uslugi': '#uslugi_faq', 'wspolpraca': '#wspolpraca_faq', 'cennik': '#cennik_faq', 'procesy': '#procesy_faq' }; // Pobierz tylko przyciski z categoryMap const buttonSelectors = Object.keys(categoryMap).map(id => `[id="${id}"]`).join(', '); const buttons = document.querySelectorAll(buttonSelectors); console.log(buttonSelectors) // Funkcja do ukrywania/pokazywania sekcji FAQ function filterFAQ(activeCategory) { // Pobierz wszystkie sekcje FAQ const allFAQSections = document.querySelectorAll('[id$="_faq"]'); // Ukryj wszystkie sekcje allFAQSections.forEach(section => { section.classList.add('hidden'); }); // Pokaż tylko aktywną kategorię const targetFAQ = document.querySelector(categoryMap[activeCategory]); if (targetFAQ) { targetFAQ.classList.remove('hidden'); } } // Dodaj event listener do każdego przycisku buttons.forEach(button => { button.addEventListener('click', function(e) { e.preventDefault(); const categoryId = this.getAttribute('id'); // Usuń klasę aktywną z wszystkich przycisków buttons.forEach(btn => { btn.classList.remove('active-category'); btn.style.color='black'; }); // Dodaj klasę aktywną do klikniętego przycisku this.classList.add('active-category'); this.setAttribute('style', 'color:white !important'); // Filtruj FAQ filterFAQ(categoryId); }); }); // Domyślnie pokaż pierwszą kategorię (#ogolne) const defaultButton = document.querySelector('[id="ogolne"]'); if (defaultButton) { defaultButton.classList.add('active-category'); defaultButton.setAttribute('style', 'color:white !important'); filterFAQ('ogolne'); } });
What types of applications do you design and develop?

We design and develop custom mobile and web applications — from MVPs and internal tools to complex, scalable digital products. This includes mobile apps (iOS, Android), web apps, SaaS platforms, dashboards, and custom business systems.

Can you help us refine or validate our app idea before development?

Yes. We often start with product discovery, UX research, and validation. We help define user flows, features, priorities, and technical scope to ensure the app solves real business problems before any code is written.

Do you handle both design and development?

Yes — we deliver end-to-end app development. From UX/UI design and prototyping to frontend, backend, integrations, testing, and launch. This ensures consistency, speed, and fewer risks during development.

Who is this service best suited for?

Our app services are designed for startups, growing companies, and established organizations that need reliable, scalable applications — whether it’s a new product, internal system, or extension of an existing platform.

What makes your app development approach different?

We focus on business outcomes, usability, and scalability — not just features. We work as a long-term partner, communicate clearly, and build apps that are easy to maintain, grow, and improve over time.

We are here for you

Let’s Build Something Great Together