01 — Gap
The store has nothing that fits
Your requirement is too specific for standard apps: shipping logic, price calculation, approval workflows. A private app solves exactly your case.
Shopify · App development · Custom
If the app you need doesn't exist — we build it.
Some requirements no store app will solve: too specific, too close to your processes, too many compromises. I build private Shopify apps that do exactly one thing right — and build my own apps on the side that prove the same craft.
Book an intro call free of charge · about 25 minutes · via video
When your own app is the right solution
Not every problem needs an app — but when three store apps have to be combined to half-solve one requirement, it's time.
02 — Compromise
Three apps getting in each other's way
App stacks create conflicts, costs and data chaos. A tailor-made app replaces the stack with one clean solution.
03 — Integration
Your system doesn't speak Shopify
ERP, PIM or inventory management without a ready-made connector: an integration app connects both worlds — error handling included.
From requirement to running app
App development is a project, not a subscription adventure: clear scope, fixed price, defined handover point.
- Step 01
Intro call
You describe the requirement, I tell you honestly whether an app is the right solution — or whether there's a simpler way.
free - Step 02
Concept & scoping
Data model, integrations, Shopify APIs: I define the scope concretely enough that a fixed price becomes possible.
from €190 - Step 03
Development
Implementation with interim releases — you watch the app grow instead of waiting for a black box.
Fixed price - Step 04
Testing in your shop & go-live
The app is tested on your shop — it only goes live once everything fits.
included - Step 05
Handover
Source code and documentation are yours — no vendor lock-in, any developer can take over.
included - Step 06
Operations & API updates
Shopify APIs change. On request I keep your app current — as part of the retainer or billed by effort.
€640 / month
All prices net. Reverse charge within the EU; invoicing by KEVIN METZDORF LTD.
Book an intro call Not sure which step fits? That's exactly what the call is for — 25 minutes, free of charge. Afterwards we'll both know whether it's a match.
Frequently asked questions
What's the difference between a private app and a store app?
A private (custom) app is installed only in your shop and built exactly for your processes — no app-store review, no monthly third-party fees, no compromises.
Which apps of your own do you build?
KM Distance Shipping — shipping rates based on actual distance, in preparation as the first release — and Cookstack, a recipe app for Shopify. Both are built with the same craft client projects get.
Do I own the app in the end?
Yes. Source code and app belong to you, and the handover is documented. You can have any developer maintain the app.
What does a custom Shopify app cost?
That depends on the scope — a lean integration app is different from a configurator. After scoping you receive a fixed price; before that I deliberately name no ballpark figures.
If you build and run your own apps in the Shopify ecosystem, you know the API pitfalls before they hit your project.
25 minutes, free of charge. Afterwards you'll know whether I'm the right fit — and what the next sensible step would be.
- 7+ years of Shopify & e-commerce
- Own apps: KM Distance Shipping, Cookstack
- Fixed price after scoping
- Apps belong to you — no lock-in