Shopify app kit · source code and agent rules
The Shopify app kit behind our 20+ apps, ready for your AI coding agent
Every app we ship starts from the same code: Shopify sign-in and tokens, webhooks and GDPR, billing plans, email and the admin UI, already done and tested. Buy the source and let your agent build only what makes your app different, or tell us the feature and we build it on the kit for you.
you Add a setting to hide PO box addresses at checkout, Pro plan only.
agent Reads CLAUDE.md and the UI and migration skills
- Migration
0007_po_box_rule.sql, numbered after production - Handler behind
billing.RequirePaid - Settings page from the shared UI system
make testpasses, checked in a dev store
left for you Review the diff and deploy
Already done when you open the repo
The parts that are hard to get right and the same in every app
We run them in production for our own apps, so they are kept up to date with Shopify's API versions and App Store requirements.
- Shopify sign-in and tokens
- Session tokens checked, token exchange, offline tokens sealed with AES-256-GCM in Postgres and renewed before they expire.
- Webhooks and GDPR
- HMAC-verified webhooks, the three mandatory privacy webhooks answered and recorded, uninstall clean-up.
- Billing plans in code
- Free and Pro plans through the Billing API, a plan page and one gate for paid features.
- Admin UI system
- Page shells, navigation, settings with a grouped menu, skeleton loading, empty states and a plan page, on Polaris web components.
- Storefront and admin extensions
- A kit for theme blocks, admin blocks and print actions that all share one look.
- Email and PDFs
- Merchant email over SMTP with a shared layout and one-click unsubscribe; PDF documents drawn on the server.
- MCP server for AI assistants
- A read-only MCP server with OAuth that merchants approve inside the app, so their assistant can read your app's data.
- Rules for AI coding agents
- Project instructions and the skills our own agents use for Shopify admin UI and SQL migrations, so an agent builds the way we do.
Buy the code, or have us build on it
Prices are where we start, not where we stop. Tell us your budget and what you need, and we reply with an offer you can accept in one email. Payment is by invoice.
Most asked for
Your app, built on the kit
from $1,900
We scope your app with you, build it on the kit and hand over the full source. A small app usually reaches a first working build in your development store within a week of an agreed scope.
- Your app's features, admin pages and extensions
- Billing, privacy webhooks and listing checks done
- Full source handed over, yours to keep
One feature, built for you
from $290
A feature in an app built on the kit, or in your existing Go or Node.js app. Usually three working days.
The kit, Solo licence
$249
Full source for one app of your own, 12 months of updates, setup notes.
The kit, Studio licence
$690
Any number of apps for you or your clients, 12 months of updates, one setup call.
Our kit or Shopify's free template?
Shopify's own template, made with shopify app init, is free, Node.js and a good start. If you want Node.js and are happy to build billing, email and the admin UI yourself, use it. Our kit is for teams who want those parts done.
| Feature | Shopify app template | StoreFleet app kit |
|---|---|---|
| Price | Free | From $249 |
| Backend | Node.js, React Router | Go, one binary with SQL migrations inside |
| Sign-in, tokens, webhooks | Included | Included, tokens sealed in Postgres |
| Billing plans and paid-feature gate | Library helpers, you build the plan page | Plans in code, plan page and gate done |
| Admin page shells and settings | One example page | Shared UI system for every page type |
| Merchant email, PDFs, MCP server | Not included | Included |
| Rules for AI coding agents | Shopify's AI Toolkit, installed separately | Project rules and skills in the repo |
Questions, answered
Is there a Node.js version of the kit?
No. Shopify's own app template, created with shopify app init, is Node.js and free, and we would rather point you to it than sell a copy of it. Our kit is Go on the backend because that is what our own apps run on. If your existing app is Node.js, we can still build features in it for you as a service.
Do I need an AI coding agent to use it?
No. It is ordinary Go and React code with tests and a Makefile. The agent instructions and skills are there so that an agent such as Claude Code follows the same rules our own agents follow, which saves you from writing those rules yourself.
What does the licence allow?
The Solo licence covers one app of your own, public or custom. The Studio licence covers any number of apps you build, for yourself or for clients. Neither allows reselling or publishing the kit itself as a template or boilerplate.
Can the price be discussed?
Yes. The prices on this page are where we start. Write with your budget and what you need, and we reply with an offer we can agree on in one email. Payment is by invoice.
How fast can you build my app?
The kit removes the parts every app needs, so the work is your own features. A small app usually reaches a first working build in your development store within a week of an agreed scope; we confirm the date before we start. Larger work is scoped as a custom app project.
Tell us what you want to build
The kit, a whole app or one feature. Send your budget with it and we reply with an offer.