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I will develop shopify private app, shopify public app, shopify custom app, shopify api
James Miller
About this gig
Need a Shopify app that does exactly what your store needs, not close to it?
I am Walker, a Shopify app developer. I build Shopify private apps, Shopify public apps and Shopify custom apps that automate your daily work, connect your other tools and handle the things themes and paid apps cannot do. I work with the official Shopify API, GraphQL, REST, webhooks and OAuth, so your app is secure, fast and built to grow with your store.
Services I offer:
- Shopify private app development
- Shopify public app development
- Shopify custom app and admin dashboard
- Shopify API and third party API integration
- Checkout extension and app extension
- Order, product, customer and inventory sync
- Webhook setup and store automation
- Subscription and recurring billing
- Bug fixing and app review rejection fix
- App Store submission support
You get clean code, plain updates you can actually follow, and delivery on time. Every app is tested on a live store before I hand it over, and I stay available after delivery.
Send me a message with your idea before you order. I will tell you the fastest way to build it and give you a fixed price and timeline today.
Respect third-party rights
Please be aware that it is against Fiverr's policies for sellers to include themes, templates, or any other elements that infringe third-party rights or applicable laws in the delivered work. Read more about in our Guide to Responsible Digital Creation.
Get to know James Miller
James Miller
I build and fix web, mobile and Shopify apps Flutter, React, no code
- FromGermany
- Member sinceAug 2026
- Avg. response time1 hour
Languages
English, German, Dutch, French, Spanish, Italian
Hi, I'm a developer who turns app and store ideas into real products. I build and fix mobile and web apps with Flutter, React, and no-code tools like Lovable, Base44, and Replit, and turn them into native iOS and Android apps with Capacitor. I also build and fix Shopify stores, from full setup and product catalogs to themes, apps, and integrations. Stuck on a bug, a broken build, an API, a Shopify setup, or a deployment that won't go live? I get it sorted fast and clean. Message me before ordering so we can map out what your project needs, and I'll tell you honestly how I'd approach it.
My Portfolio
FAQ
Is a private app the same thing as a custom app now?
Yes. Shopify renamed private apps to custom apps. A custom app is installed on your store only and is not listed on the App Store. If you say private app, I know what you mean and I build it the same way.
Do I need a public app or a custom app?
If the app is only for your own store or a few stores you own, you need a custom app. It is faster and cheaper because there is no review process. If you want to sell it to other merchants, you need a public app. Tell me your goal and I will tell you which one
My app got rejected by Shopify App Store review. Can you fix it?
Yes. Most rejections come from missing GDPR webhooks, wrong OAuth or session token handling, slow load times, or a listing that does not match what the app does. Send me the rejection email and I will tell you what needs to change befo
Will the app slow down my store?
No. Backend work runs on my server, not on your storefront. Anything that touches the front end is built as a theme app extension, which is the method Shopify recommends and scores well on speed tests.
Where will my app be hosted and what does that cost?
Your app needs a server to run on. I set it up on a host you own, so you keep control. Small apps usually cost a few dollars a month. I will give you the exact number for your project before we start, and it is paid to the host, not to me.
What access do you need from me?
Collaborator access to your Shopify admin, or a staff account with the right permissions. I never need your password. If you have third party services to connect, I will need API keys for those. I will send you a short list once we agree the scope.
My webhooks keep failing or firing twice. Can you sort that out?
Yes. Duplicate and missed webhooks are one of the most common problems merchants have. I fix it with proper verification, retry handling and a queue so nothing is processed twice and nothing is lost.
Can you connect my store to another system I already use?
Yes. That is most of my work. ERP, CRM, shipping and courier services, payment gateways, accounting tools, warehouses. If the other system has an API, I can sync orders, products, inventory and customers between it and Shopify.
Do I own the code?
You do. You get the full source code and the repository at delivery. Nothing is locked to me, and any developer can pick it up later.
What happens after delivery if something breaks?
I fix bugs in the work I delivered at no cost. If you want new features later, we agree a separate price. Message me any time and I will reply within a few hours.
