Shopify App Development & Custom Solutions for Your Business

We build custom Shopify apps, develop tailored features and create high-performing stores that convert.

  • Private & Public Shopify Apps – from concept to App Store
  • Custom Shopify Development with Liquid, React & Node.js
  • API Integrations: ERP, CRM, Inventory & more
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Marvin Siekmann, Co-Founder & CTO von CodeThat – Shopify App Entwicklung & Custom Development

Marvin Siekmann

Co-Founder & CTO

Trusted by

Sound familiar?

Many Shopify merchants struggle with the same problems. We solve them.

Your store is growing, but the tech isn't keeping up

Manual processes, missing automation, and a tech stack that doesn't scale – costing you time and revenue.

Freelancers deliver code, not strategy

The code works, but nobody thinks about maintainability, performance, or next steps.

App Store apps don't fit 100%

Standard apps solve 80% of the problem. The last 20% cost you conversions and customer satisfaction.

Integrations take forever

ERP, CRM, inventory – your systems don't talk to each other and your team works with copy-paste.

What Our Clients Say

„CodeThat redesigned our online shop and guided us with great expertise throughout the project. The team was always quick to respond, focused on solutions and delivered on every request. We're very happy with the result and the value for money is spot on.“
Laurin Krausz
Laurin Krausz Secend
„We have been working with CodeThat for several years and have not only optimized our Shopify store, but also adapted and modernized our entire CRM system so that all figures and facts are now available in real time. Industrial-grade standards for the trades. Absolutely amazing!“
Marvin Kobus
Marvin Kobus MIK Motoren
„We're completely satisfied with the collaboration. Service, communication and execution were consistently professional, reliable and pleasant before, during and after the project. Everything was implemented exactly as we envisioned. We highly recommend working with CodeThat and look forward to future projects together.“
Dominik Gebhartl
Dominik Gebhartl Purora
„We've had the pleasure of working with CodeThat for a few years now across multiple stores. Their team consistently listens to our needs and flawlessly brings our website visions to life. What truly sets them apart is how they always go the extra mile, offering brilliant recommendations and solutions we wouldn't have thought of ourselves. We wholeheartedly recommend CodeThat to any Shopify store owner looking for top-notch customization and expert coding. Thank you, CodeThat!“
J
Jean-Marc Truong Semco
„CodeThat were instrumental in accelerating our Shopify app development. They are true experts when it comes to Shopify and added real value from the design and planning of our app through to implementation and launch. It has been a pleasure working with them throughout the process, and we have always felt that we were in very good hands with a team that genuinely understands Shopify apps. We would highly recommend CodeThat to anyone looking for an experienced and reliable Shopify app development partner.“
Peter Rose
Peter Rose Mapular
„We have been working with the team for around 7 years and are extremely happy. The collaboration is straightforward, reliable and always at eye level. Requests get implemented quickly and you can tell they really think along and find solutions. Exactly what you would hope for. Clear recommendation.“
R
Raimund Hoffmann Süß und Clever
„CodeThat redesigned our online shop and guided us with great expertise throughout the project. The team was always quick to respond, focused on solutions and delivered on every request. We're very happy with the result and the value for money is spot on.“
Laurin Krausz
Laurin Krausz Secend
„We have been working with CodeThat for several years and have not only optimized our Shopify store, but also adapted and modernized our entire CRM system so that all figures and facts are now available in real time. Industrial-grade standards for the trades. Absolutely amazing!“
Marvin Kobus
Marvin Kobus MIK Motoren
„We're completely satisfied with the collaboration. Service, communication and execution were consistently professional, reliable and pleasant before, during and after the project. Everything was implemented exactly as we envisioned. We highly recommend working with CodeThat and look forward to future projects together.“
Dominik Gebhartl
Dominik Gebhartl Purora
„We've had the pleasure of working with CodeThat for a few years now across multiple stores. Their team consistently listens to our needs and flawlessly brings our website visions to life. What truly sets them apart is how they always go the extra mile, offering brilliant recommendations and solutions we wouldn't have thought of ourselves. We wholeheartedly recommend CodeThat to any Shopify store owner looking for top-notch customization and expert coding. Thank you, CodeThat!“
J
Jean-Marc Truong Semco
„CodeThat were instrumental in accelerating our Shopify app development. They are true experts when it comes to Shopify and added real value from the design and planning of our app through to implementation and launch. It has been a pleasure working with them throughout the process, and we have always felt that we were in very good hands with a team that genuinely understands Shopify apps. We would highly recommend CodeThat to anyone looking for an experienced and reliable Shopify app development partner.“
Peter Rose
Peter Rose Mapular
„We have been working with the team for around 7 years and are extremely happy. The collaboration is straightforward, reliable and always at eye level. Requests get implemented quickly and you can tell they really think along and find solutions. Exactly what you would hope for. Clear recommendation.“
R
Raimund Hoffmann Süß und Clever
Marvin Siekmann

Marvin

Co-Founder & CTO, CodeThat

Ready for your Shopify project?

Tell us about your plans. We'll get back to you within 24 hours.

After launch

Your store is live? We stay.

Most agencies disappear after the project. With CodeThat Pro we take long-term ownership of your Shopify store – as your external development team.

  • Shopify development & feature improvements
  • CRO and SEO improvements
  • Performance optimization & bug fixes
  • Integrations, automations & infrastructure
  • One team for everything technical
Learn about CodeThat Pro

Our Team

Experienced developers and e-commerce specialists who make your Shopify project a success.

Marvin

Marvin

Co-Founder & CTO

Denise

Denise

Co-Founder & Admin

Jerome

Jerome

Project Manager

Patryk

Patryk

Full-Stack Developer

Szymon

Szymon

Full-Stack Developer

Frequently Asked Questions

How much does a custom Shopify app cost?

Costs depend on complexity and scope. A simple private Shopify app starts at around €5,000, while more complex public apps with admin UI and integrations range from €15,000-40,000. We're happy to provide a custom quote.

How long does Shopify app development take?

A simple private app can be ready in 2-4 weeks. More complex apps with integrations and custom UI take 6-12 weeks. We work agile and deliver regular updates.

Do you only work with Shopify Plus?

No, we work with all Shopify plans – from Basic to Shopify Plus. However, Shopify Plus stores offer additional capabilities like checkout extensions and extended API limits.

Can you modify or extend existing apps?

Yes, we also handle further development of existing Shopify apps. Whether bug fixes, new features or performance optimization – we're happy to help.

What integrations can you build?

We integrate virtually any REST or GraphQL API: ERP systems (SAP, Microsoft Dynamics), CRM (HubSpot, Salesforce), inventory management, payment providers and more. Learn more about our Shopify integration services.

Do you offer ongoing support?

Yes, we offer flexible support packages for ongoing store maintenance and optimization, bug fixes and feature extensions. This keeps your store always up to date.

Do I still need you – with what AI can do today?

AI is a genuine game-changer – for us too. Things that used to take weeks now take days. What has not changed: complex Shopify projects still need someone who understands the architecture, makes the calls and takes responsibility at the end. AI generates solutions faster, but it does not know your store, your requirements or your deadline. We do. The result: you get the speed of AI and the reliability of an experienced team.

Do you use AI in your development work?

Yes, and we think that is exactly right. AI makes us faster – and that benefit passes directly to you. Routine work moves quicker, which means we can spend more time on the parts that genuinely need expertise. The difference from just running everything through AI: we understand what comes out, review it and stand behind it. You get the advantages of modern tooling without the quality loss that happens when nobody is actually looking.

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