01
Custom Shopify apps
Private tools for one business: bulk editors, approval flows, B2B order tools and reports, embedded in the Shopify admin.
FIG 01 · Shopify App Development
A Shopify app development company for the GraphQL-only, Functions-first platform
Custom apps for one merchant and public apps for the Shopify App Store, built on the GraphQL Admin API with Polaris and App Bridge, plus migrations off Shopify Scripts and script tags before they stop working.
See how it works
FIG 02 · Quick answer
What is Shopify app development?
Shopify app development means building apps that extend a Shopify store or sell on the Shopify App Store. Elgrith builds custom apps for one merchant and public apps for many, on the GraphQL Admin API with Polaris and App Bridge, and migrates Shopify Scripts to Functions and script tags to theme app extensions.
- Admin API from day one, never legacy REST
- GraphQL
- Projects delivered since 2015
- 1,000+
- Clients across the USA, UK and India
- 250+
- Your code, designs and IP
- 100%
FIG 03 · Why it matters
Shopify changed how apps are built. Older apps have deadlines.
From shopify.dev’s API docs and developer changelog, read on 23 Oct 2026.
01
1 Apr 2025
New public apps must be GraphQL-only
Shopify: “Starting April 1, 2025, all new public apps must be built exclusively with the GraphQL Admin API.” The REST Admin API has been legacy since 1 Oct 2024.
Source: shopify.dev, REST Admin API (legacy notice)(opens in a new tab)02
30 Jun 2026
Shopify Scripts stopped running
Shopify’s changelog: “June 30, 2026—All Shopify Scripts will cease to execute entirely.” Discount, shipping and payment logic that lived in Scripts now has to be a Shopify Function.
Source: shopify.dev changelog, Shopify Scripts deprecation (9 Apr 2026)(opens in a new tab)03
1 Mar 2027
Script tags stop being injected
Shopify’s changelog (24 Aug 2026): “On March 1, 2027, Shopify will stop injecting script tags into storefronts.” Apps that add storefront code that way need theme app extensions before that date.
Source: shopify.dev changelog, online store script tags (24 Aug 2026)(opens in a new tab)
FIG 04 · Decide
Custom vs public Shopify apps: which do you need?
A custom app is built for one business. A public app is a product you sell to many merchants. The choice changes how the app is installed, reviewed and billed.
| Custom app | Public app | |
|---|---|---|
| Built for | One merchant’s own workflows | Many merchants, as a product |
| Installed on | One store, stores in the same Plus organisation, or development stores | Many Shopify stores |
| Shopify review | No approval step | Approval before distribution |
| Billing | Can’t charge through Shopify’s app billing; you invoice directly | Shopify Billing API: 0% revenue share on the first US$1M lifetime, then 15%, plus a 2.9% processing fee |
| Shopify Functions | Only on stores on a Shopify Plus plan | Stores on any plan, via the App Store |
| Built for Shopify badge | Not applicable | Optional: 50 net installs, 5 reviews and performance thresholds |
From shopify.dev’s distribution, Functions, revenue share and Built for Shopify pages, read 23 Oct 2026. Shopify changes these terms; we re-check them in every written scope.
Running Shopify Plus? Shopify Plus developmentFIG 05 · What you get
Shopify app development services
Shopify app development for merchants, agencies and app founders: admin tools, integrations, checkout logic and storefront features, built on the APIs Shopify supports now.
02
Public App Store apps
Apps you sell to many merchants, built to pass Shopify’s review, with OAuth install, the Billing API and a listing ready to submit.
03
ERP, PIM, 3PL and CRM sync
Orders, stock, prices and customers kept in step with your other systems through webhooks, queues and the GraphQL Admin API.
04
Shopify Functions
Discount, shipping, payment and validation logic as Functions, including rebuilds of old Shopify Scripts.
05
Checkout UI extensions
Fields, upsells, notices and delivery options added to checkout with extensions, not theme hacks.
06
Theme app extensions
App blocks and embeds merchants place in the theme editor, replacing storefront script tags.
07
Embedded admin UI
Admin screens in Polaris, embedded with App Bridge, so the app looks and works like the rest of Shopify.
08
Metafields and metaobjects
Custom data models for products, customers and content, stored in Shopify instead of a side database where possible.
Deliverables
11
deliverables, in writing
Included in every build, written into your fixed quote before work starts.
FIG 06 · Custom apps
Custom Shopify app development
Most custom apps connect Shopify to the systems that already run the business, or add the admin tool the team keeps doing by hand.
- ERP
- PIM
- 3PL / warehouse
- CRM
Your Shopify store
- Admin app
- Functions
- Checkout extension
- Theme app block
ERP sync
- Sync
- Orders out, stock and prices in
- How
- Webhooks, a queue and retries, so a busy day doesn’t drop orders
PIM and catalogue tools
- Sync
- Products, variants, media and metafields
- Why
- One source of product truth across channels
3PL and fulfilment
- Sync
- Fulfilment orders, tracking and returns
- Watch
- Shopify API rate limits on large catalogues
CRM and loyalty
- Sync
- Customers, tags and order history
- Use
- Segments for email, SMS and sales teams
B2B pricing and discounts
- Build
- Discount and validation Functions
- Note
- Custom apps with Functions need a Plus plan
Admin tools
- Build
- Bulk editors, approval queues, reports
- UI
- Polaris inside the Shopify admin
FIG 07 · Flagship build
Proof: product engineering we’ve shipped
Kenerate AI is our flagship build, an all-in-one AI studio. It is not a Shopify app; it shows the API-heavy engineering and AI features we’ve shipped: many providers behind one account, one login and one credit balance.
- 200+ AI models behind one app, one login and one credit balance
- MCP & CLI: Kenerate works inside Claude, ChatGPT, Cursor and 19+ AI apps
- 23+ studios and tools, with up to 4K output
- 1,000+ projects for 250+ clients since 2015
Home: one prompt box for image, video and musicDesigned and engineered by Elgrith
- AI models in one app
- 200+
- Studios and tools
- 23+
- Maximum output
- 4K
- Guides
- 500+
FIG 08 · App Store
Public apps for the Shopify App Store
A public app is a product. It has to pass Shopify’s review, install cleanly on any store and stay fast inside the admin.
06principles
OAuth install and scopes
Token exchange, the smallest set of access scopes the app needs, and clean uninstall handling.
Review-ready from sprint 1
Shopify’s app requirements in the acceptance criteria, so submission isn’t a last-minute rewrite.
Billing API
Plans, trials and usage charges through Shopify billing, which Shopify settles with you.
Built for Shopify budgets
Admin LCP, CLS and INP measured against Shopify’s thresholds in every release.
Mandatory privacy webhooks
Customer data requests and erasure handled, plus HMAC checks on every webhook.
AI features in your app
Product copy, search and support features built on large language models.
Generative AI development
FIG 09 · Deadlines
Migrate before the deadlines
Three platform changes create work for older stores and apps. Dates from shopify.dev, checked 23 Oct 2026.
06principles
Scripts → Functions
Shopify Scripts stopped running on 30 June 2026. We rebuild the discount, shipping and payment logic as Functions and test it against your old rules.
Script tags → theme app extensions
Shopify stops injecting script tags into storefronts on 1 March 2027. We move storefront code into app blocks and embeds before then.
REST → GraphQL
REST Admin API calls rewritten as GraphQL queries and mutations, with bulk operations for large catalogues.
Legacy app rescue
Older apps moved onto the current Shopify CLI template, App Bridge and session handling, one area at a time.
FIG 10 · Stack
Our Shopify app stack
We start from Shopify’s own tooling, so the app keeps working as the platform moves.
06principles
Shopify CLI, React Router template
Apps scaffolded from Shopify’s current React Router template, with extensions in the same repository.
Polaris and App Bridge
Admin UI in Polaris, embedded with the latest App Bridge, as Built for Shopify expects.
Webhooks and queues
Webhook subscriptions feeding a queue with retries and idempotent handlers, so nothing is processed twice.
FIG 11 · Measurement
Built for Shopify budgets in the acceptance criteria
For public apps, we test against Shopify’s published Built for Shopify thresholds before every release, not after review.
| Measure | Shopify’s threshold | How we check it |
|---|---|---|
| Largest Contentful Paint (admin) | 2.5 seconds or less | Web Vitals on the embedded app, on staging and in production |
| Cumulative Layout Shift | 0.1 or less | The same Web Vitals reporting |
| Interaction to Next Paint | 200 milliseconds or less | The same Web Vitals reporting |
| Embedding | Latest App Bridge in the Shopify admin | Checked in code review |
| Net installs and reviews | 50 net installs from paid shops, 5 reviews | Tracked after launch; these come from merchants, not code |
From shopify.dev’s Built for Shopify requirements, read 23 Oct 2026. Shopify awards the badge; we build to the criteria but can’t promise it.
FIG 12 · Process · 6 steps
Scope it, build it, ship it on time
A fixed written quote after a free call, sprints with weekly demos on a development store, and a launch planned around Shopify’s deadlines. You own the code and IP.
- Step 01
Free call
Tell us what you want to build or fix. We ask about users, data, integrations and deadlines before we talk about tools.
- Step 02
Review
For a new app: users, data, the Shopify APIs and scopes it needs, and whether it should be custom or public. For an existing app: REST calls, Scripts, script tags and anything on a deadline.
- Step 03
Fixed written quote
A written scope, a fixed quote and the plan for hand-over, before any work starts.
- Step 04
Sprints with weekly demos
Two-week sprints in your repository, with a development store to click through and a demo every week.
- Step 05
Launch
A custom app installed on your store, or a public app submitted for Shopify’s review with a listing, screenshots and test instructions.
- Step 06
Support
API version upgrades each quarter, fixes in a window agreed in your written scope, and new features as Shopify releases them.
FIG 13 · What you get
Everything included
Written into your fixed quote, so you know exactly what you are paying for before work starts.
11items
- Written scope and fixed quote
- Custom vs public app decision, in writing
- App code in your repository, IP assigned to you
- GraphQL Admin API integration
- Polaris admin UI embedded with App Bridge
- Functions and extensions, if needed
- Webhook handling with retries
- Development store for demos and QA
- App Store listing and review notes (public apps)
- API version upgrade plan
- Runbooks and hand-over notes
FIG 14 · Tech & tools
The tools behind the work
Proven, well-supported tools, chosen for your project and set up in accounts your business owns.
- Shopify CLI
- React Router
- Polaris
- App Bridge
- GraphQL Admin API
- Storefront API
- Shopify Functions
- Checkout UI extensions
- Theme app extensions
- Webhooks
- Metafields
- Metaobjects
- Shopify Billing API
- OAuth
- Node.js
- TypeScript
- React
- PostgreSQL
- Redis
FIG 15 · Who it’s for
Shopify apps for merchants and app founders, in the US and UK.
Same rules for all three: the current Shopify APIs, your repository, your IP.
3 audiences
Merchants
A custom app for the way your store works.
Integrations, admin tools and checkout logic for one business, installed on your store, with no App Store review to wait for.
- ERP, PIM, 3PL and CRM sync
- Functions on Shopify Plus stores
- Scripts and script-tag migrations
- No App Store listing needed
App founders
A public app ready for the App Store.
An app built as a product: OAuth install, Shopify billing, Built for Shopify performance budgets and a listing ready for review.
- Billing API plans and trials
- Review-ready requirements
- Admin Web Vitals tracked
- Quarterly API upgrades
UK teams
Shopify app development for UK merchants.
UK projects run through our London client partner, with engineering at our New Delhi HQ. We write in UK English, quote in GBP and design data handling around UK GDPR.
- London client partner
- UK English throughout
- Fixed written quote in GBP
- UK GDPR-aware data handling
FIG 16 · Working with us from the USA and UK
Built in New Delhi. Run on your hours.
Every project gets a point of contact in New York or London and an engineering team in New Delhi. Here is how today’s working days line up, live.
New York
North America
--:--ET
New Delhi team Your working day- Shared working time
- ≈ 3 hours today
- New Delhi is
- 10.5 h ahead
- Live calls, your time
- 9 a.m. to 12 p.m. ET
London
UK & Europe
--:--UK
New Delhi team Your working day- Shared working time
- ≈ 4.5 hours today
- New Delhi is
- 5.5 h ahead
- Live calls, your time
- 9 a.m. to 1:30 p.m. UK
Three ways to work together
- 01
Fixed-scope project
A written scope, one fixed price and a dated plan. Suits websites, apps and MVPs.
- 02
Dedicated team
Designers and engineers on your roadmap every month, billed monthly.
- 03
White label
For US and UK agencies: our work, your brand, unbranded deliverables.
Every engagement
- Fixed quote in USD, GBP or INR after a free 30-minute call
- NDA before discovery. You own all code, designs and content
- A working demo every sprint, not status slides
- Reply within one business day, calls inside your hours
Book a call
Calls on ET or UK hours
FIG 17 · Cost
What drives the cost of a Shopify app
What drives Shopify app development cost? We don’t publish rates. These are the things that move the quote most.
| Driver | Pushes cost up | Keeps cost down |
|---|---|---|
| Distribution | Public app: review, billing, support for many stores | Custom app for one store |
| Integrations | Several systems, two-way sync, large catalogues | One system, one direction |
| Checkout logic | Several Functions and checkout extensions | Admin-only features |
| Admin UI | Many screens and roles | A few Polaris screens |
| Legacy code | Scripts, script tags and REST calls to replace | A new build on current APIs |
| Shopify’s own fees | Public apps: 15% above US$1M lifetime revenue, 2.9% processing | Custom apps: no Shopify billing at all |
Shopify’s fees from shopify.dev’s revenue share page, read 23 Oct 2026. After a free call you get a written scope and a fixed quote.
Weighing Shopify Plus for Functions? Shopify vs Shopify Plus (2026)FIG 18 · Compare
Custom app, off-the-shelf app or theme code?
| Custom app (built for you) | Off-the-shelf App Store app | Theme code edits | |
|---|---|---|---|
| Best for | Workflows and integrations unique to you | Common needs many stores share | Small storefront changes |
| Fits your process | Exactly | As far as its settings go | Storefront only |
| Runs in | Admin, checkout, storefront and back end | Wherever the vendor built it | Storefront theme |
| Who owns the code | You | The vendor | You |
| Ongoing cost | Hosting and upkeep | Monthly subscription | Theme upkeep |
| Our page | You are here | We can integrate it | Ecommerce development |
FAQ
Frequently asked questions
Straight answers about Shopify App Development with Elgrith.
It depends on whether the app is custom or public, how many systems it connects to, whether it needs Functions or checkout extensions, and how much legacy code it replaces. We don’t publish rates; after a free call you get a written scope and a fixed quote. Public apps also pay Shopify’s fees once revenue passes US$1M.
FIG 19 · Related
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Free 30-minute call
Build your Shopify app on the current platform.
Tell us what the app should do, or which Scripts and script tags you need to move. After a free call you get a written scope and a fixed quote.
Pick a day for your call
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