Custom (private) apps
Apps built for one store or organization: internal tools, admin workflows and integrations that fit how you work.
Service 04
Custom Apps & Extensions
Custom Shopify apps and extensions add features your store needs that no off-the-shelf app provides. FleekApps builds private and public Shopify apps, Shopify Functions, checkout UI extensions, theme app extensions and admin extensions, the same way we build and ship our own apps, FunctionFlow AI and SmartSort AI.
01
What’s included
Public App Store apps
Embedded apps with App Bridge, Shopify Billing, GDPR webhooks and everything needed to pass App Store review.
Shopify Functions
Discount, delivery, payment, validation and cart transform functions in Rust or JavaScript, compiled to WebAssembly.
Checkout & account UI extensions
Custom fields, upsells, banners and loyalty blocks in checkout, Thank you and customer account pages.
Theme app extensions
App blocks and embeds merchants add in the theme editor, with no theme code edits.
Admin extensions & Flow
Admin actions, blocks and Shopify Flow triggers and actions that bring your logic into the Shopify admin.
02
Who it’s for
Merchants with unique workflows
Your process does not fit an existing app, or you are paying for five apps to do one job.
Agencies and partners
You need a dependable app team for a client build or extension.
Founders with an app idea
You want to launch a public Shopify app with people who have done it.
03
How we work
- 01
Discover
We learn your store, numbers, stack and goals, then agree what success looks like and how we will measure it.
- 02
Design
Flows, interfaces and architecture, reviewed with you before a line of production code is written.
- 03
Build
Short cycles with working previews on a development store, so you see progress every week.
- 04
Launch
QA on real devices and real checkouts, a rollout plan, and monitoring from day one.
- 05
Grow
We measure the result, then iterate: experiments, automations and new features on a monthly rhythm.
04
Tools & platforms
- Shopify CLI
- App Bridge
- Polaris
- Shopify Functions
- Rust
- WebAssembly
- Remix
- Laravel
- Vue
- Admin GraphQL API
- Billing API
05
Our apps that help
06
FAQ
What is the difference between a custom app and a public app?
A custom app is built for a single store or organization and is not listed on the Shopify App Store. A public app is listed on the App Store, can be installed by any merchant, and has to pass Shopify’s review. We build both.
Do custom apps with Shopify Functions need Shopify Plus?
Yes. Only stores on Shopify Plus can use custom apps that contain Shopify Functions. Stores on any plan can use public apps that contain Functions, which is why FunctionFlow AI works on every plan.
Who owns the code?
You do. Custom work is delivered in your repository, with documentation and deployment instructions.
Can you help us get a public app approved?
Yes. We have taken our own apps through the App Store requirements: embedded App Bridge apps, session-token auth, Shopify Billing, mandatory GDPR webhooks and listing assets.
07
Other services
- 01 Shopify Plus Development Custom themes, checkout extensibility, B2B, Markets and headless builds for high-volume Shopify Plus stores.
- 02 AI Automations AI agents and workflows for product content, support, merchandising and operations, connected to your Shopify data.
- 03 Conversion Rate Optimization Research, A/B tests and UX improvements across collections, product pages, cart and checkout.
- 04 Enterprise Integrations Reliable, monitored connections between Shopify and your ERP, PIM, OMS, WMS, CRM and accounting systems.
- 05 eCommerce Scaling A technical growth roadmap: performance, peak readiness, international expansion and automation.
Let’s talk about custom apps & extensions.
Tell us about your store and what you want to change. We will come back with questions and a suggested next step.