Custom Shopify app development
Hire Shopify app developers who build and run their own apps
A team of Shopify app developers since 2021, from the storefront and checkout to orders, shipping and the back office. We bring that experience to custom apps, integrations and ongoing development for merchants and agencies.
- Building for e-commerce
- since 2021
- Shopify work
- more than five years
- Shopify apps we have built
- 20+
Three ways to work with us
Pick the one that matches the work. You can start with one and move to another later.
For apps you already run
Ongoing development, month to month
Developers on your app or integration as your team needs them, without hiring in-house: one list of priorities, a short note each month, and nobody to onboard twice.
- New features and fixes as your business changes
- API versions, webhooks and monitoring kept up to date
- The same developers every month, who know your store
For a known job
A project with a clear scope
One app, integration or migration with an agreed result. We reply to your brief with an approach and an estimate, and building starts once you agree to them.
- A custom app, a Shopify Function or an integration
- Scripts to Functions, REST to GraphQL, or an API version upgrade
Before you commit
A review before you build or switch
A short technical review of a planned app, or of one another developer built, before you commit to more.
- What Shopify allows on your plan, and what is at risk
- A written list of what we would do first
Building it yourself? Buy the app kit our apps are built on.
Four kinds of work
All for Shopify, each from what your team needs
Every piece starts from what Shopify allows for your store and plan.
When custom makes sense
And when it does not
Shopify already offers several ways to change how a store works. Check these in order; custom work earns its place when none of them fits.
An existing app
If a public app on the Shopify App Store already does the job, start there. Public apps go through Shopify's App Store review and work across many stores.
Shopify Flow
A Shopify app on Basic, Grow, Advanced and Plus that runs workflows of triggers, conditions and actions. Its Send HTTP request action, on Grow, Advanced and Plus, can call a system of yours; that other end may be what needs building.
Shopify Functions
Custom backend logic for discounts, payments, delivery options, cart and checkout validation, bundles and fulfillment constraints, delivered inside an app. Only Shopify Plus stores can use custom apps that contain Function APIs; public apps with functions work on any plan.
Custom work
When the job depends on your own data, your other systems or your own approval steps, and nothing above covers it. A custom app is made for a single store, or for stores in the same Plus organization, without App Store review.
Platform changes that often need custom work
Shopify retires and replaces parts of its platform on a schedule. These recent changes can leave an older custom app, script or integration behind; each comes from Shopify's own documentation.
Jun 30, 2026
Shopify Scripts ended
Scripts still published were deactivated and no longer work. Their logic moves to Shopify Functions, delivered inside an app.
Jan 1, 2026
New custom apps come from the Dev Dashboard
New custom apps are created in the Dev Dashboard or with Shopify CLI, not in the Shopify admin. Existing admin-created apps keep working.
Oct 1, 2026
Market-driven shipping is rolling out
Shipping settings move from delivery profiles into Markets; every merchant moves by July 1, 2027. On these stores, apps that read or write merchant-owned delivery profiles may see stale data or writes that change nothing.
Aug 26, 2026
Thank you and Order status pages
checkout.liquid and additional scripts were sunset for these pages on August 28, 2025, and August 26, 2026 was the deadline for non-Plus stores to upgrade them.
Every 3 months
API versions expire
Shopify releases a new API version every three months and supports each stable version for at least 12 months. A request to an unsupported version is answered by the oldest supported one, which can quietly change results.
Apr 1, 2025
REST Admin API is legacy
Legacy since October 1, 2024. Since April 1, 2025, new public apps must be built only with the GraphQL Admin API.
What we have built
Our own apps, live on the Shopify App Store
The rules and platform changes we handle for you are ones we already handle for ourselves.
Wayvo
An order tracking page in the theme: buyers enter order number and email to see status, carrier and items.
- Theme app block
- Fulfillment data
- Seven languages
Etiketto
Nutrition tables, ingredients and bold allergens on product pages, edited inside the Shopify admin.
- Theme app extension
- Admin blocks
- Metafields
Columna
Orders to CSV or Excel with line-item properties, laid out in the browser, plus Google Sheets.
- Admin actions
- Direct API access
- CSV and XLSX
Grammo
Packaging placed on the market per country, material and period, taken from delivered shipments.
- Fulfillment data
- LUCID and Citeo exports
Tarifo
Commercial invoices, proformas and CN23 forms from orders, with missing customs data flagged before shipping.
- PDF documents
- Bulk actions
Payora
Hide, rename or reorder payment methods at checkout by cart, delivery, customer and order history.
- Shopify Functions
- Simulator
Paperly
Invoices, packing slips, credit notes and quotes as PDF, with totals that match the order.
- PDF documents
- Bulk actions
- Draft orders
Knotly
Paid gift wrap and gift messages on the product page or in the cart, with message rules checked at checkout and printed cards.
- Shopify Functions
- Checkout validation
- Packing slips
How a project runs
Your live store changes only when you have seen the work and approved it.
Send a short brief
Your goal, the tools you use, the stores involved and a deadline if you have one. A few lines are enough.
Get our approach
We reply with how we would build it, what Shopify allows on your plan, the risks we see and an estimate.
We build and test it
On a development store first, with your sample data, so you see it working before it reaches your store.
Go live, then keep it running
We release it with your sign-off, then keep it up to date for you or hand it over with documentation.
A short brief is enough
A few lines on each point
Skip anything you do not know yet. The email opens with these questions filled in.
- Goal
- What you want to build or fix, and what changes for your team when it works.
- Current tools
- The apps, spreadsheets and systems you use today, and what should connect to what.
- Stores
- Which Shopify stores are involved, and their plans if you know them; some options depend on the plan.
- Data
- What it needs to read or change: orders, products, stock, customers or something else.
- Who approves
- Who on your side signs off on changes, and which actions should always wait for a person.
- Deadline, if any
- A date you are working toward, such as a Shopify change or a launch.
Questions, answered
What do you build?
Custom Shopify apps for a workflow no ready-made app fits, integrations between Shopify and the tools you already use, back-office tools of your own, and servers built for your solution. We have also started building agents and MCP tools for a team's own process, with a person approving risky actions; that offer is new.
What experience does your team have?
More than five years. We are a team of Shopify app developers who have built for e-commerce since 2021, across the storefront, checkout, orders, shipping, stock, compliance and the systems around them. Today we build and run Shopify apps of our own that use the GraphQL Admin API, webhooks, Shopify Functions, theme app extensions and admin extensions, and we support their merchants ourselves.
Can we hire a developer month to month?
Yes. Besides projects with a fixed scope, we take on ongoing work for an app or integration you already run: new features, fixes, Shopify API version upgrades and monitoring. Tell us roughly how much work you expect each month and we will tell you plainly whether it fits.
Can you take over an app another developer built?
Yes. We start with a short review of the code, where it runs, which accounts own the app and its credentials, its API version and its webhooks. You get a written list of what works, what is at risk and what we would fix first, before any larger commitment.
What does a custom Shopify app cost, and how long does it take?
It depends on the scope, the systems it connects to and the upkeep it needs, so we reply to each brief with an approach and an estimate rather than a price list. When the app fits our app kit, a build starts from $1,900 and a single feature from $290.
Can you work with our agency?
Yes. Write to us about a client's store as you would about your own. Shopify's API terms do not allow one custom app to be made available to more than one merchant, so work for several clients is scoped one merchant at a time. If someone needs access to a store, Shopify's collaborator accounts let the store owner choose which sections they can open.
How do I start?
Email hello@reply.getstorefleet.com with a short brief: your goal, the tools you use today, the stores involved, the data it needs, who approves changes, and a deadline if you have one. The email opens with those questions filled in. We reply with how we would approach it.
Read more on the blog
Create a Shopify Custom App in the Dev Dashboard (2026 Guide)
Since January 2026, new custom apps come from the Dev Dashboard or Shopify CLI. How to create one, set scopes, get tokens, install it, and keep the app in your hands.
How to Maintain a Custom Shopify App: Routine and Handover
API versions, webhooks, logs, hosting, secrets and platform changes: what keeping a custom Shopify app alive involves, plus a routine and a handover checklist.
Market-Driven Shipping: Audit and Update Your Custom App
Shopify is moving shipping into Markets from October 1, 2026. Why apps that use delivery profiles see stale data or silent no-op writes, and how to fix yours.
A Shopify AI Agent That Waits for Your Approval: How to Build It
How to build an AI agent or MCP tool for a Shopify store that prepares refunds, stock and price changes while a person approves the risky ones: scope, logs, checks.
Shopify API Version Upgrade: A Quarterly Checklist for Custom Apps
Shopify ships a new Admin API version every three months. How to find the version your custom app calls, read the release notes, test the upgrade and deploy it safely.
Shopify Checkout UI Extensions: What You Can Add, and Where
Checkout UI extension targets for checkout, Thank you and Order status pages, which ones need Shopify Plus, the limits they run under, and when an app is enough.
Hire the team behind our own Shopify apps
Send a few lines about the job: a new app, an integration or an app that needs a new owner.