01/04
Impact audit
Lighthouse, Core Web Vitals, funnel drop-offs, app stack review, crawl health, before scoping anything.
What changes
You find out where the revenue is leaking before you pay anyone to build.
Custom Shopify Development
Shopify Development Agency That Scopes Against Revenue, Not Wireframes
Most agencies build to a spec and invoice on launch. We put a number on the build before code ships, then check it 30 days later. If it misses, we iterate for free.
Trusted by Shopify brands
Not a reskinned theme
What is custom Shopify development, and how is it different?
Custom Shopify development is building the parts of your store the platform does not give you. Not a theme you bought and recoloured. Bespoke sections, checkout logic, private apps, automation, and the integrations that make your operation actually work.
The difference from general web development is that Shopify decides a lot for you. You cannot touch checkout unless you are on Plus. Apps are easy to install and quietly cost you page speed. Liquid renders server-side, which most developers coming from React get wrong. Shopify custom development is knowing which of those constraints to work inside and which to build around, and the answer changes depending on what the feature is actually worth to you.
The four pillars
Every engagement covers the same four pillars
Each pillar has a named outcome you can check against.
02/04
Revenue model
A projected number attached to the build. Lift LCP by 1.5s, conversion rises by X. Agreed before code.
What changes
You know what you are buying, and so do we.
03/04
Build sprint
Two-week sprints, daily updates, staging preview on day 7, delivered day 14. You sign off before anything goes live.
What changes
You see it working before it ships, not after.
04/04
30-day check
Performance measured against the projection. If it underperforms, we iterate at no extra cost.
What changes
The number is the contract, not the wireframe.
Every build includes a 30-day post-launch support window at no extra cost.
Common mistake
Most stores scope a build by feature list
The list never says what any of it is worth.
An agency sends a proposal with twenty line items and a price. Everything gets signed off, everything gets built, nobody checks whether conversion moved. If it did not, that becomes your problem at the next renewal.
The threshold that matters most: if a feature can be built in Liquid in under eight hours, it should never be an app. Apps add JavaScript on every page load, a monthly fee, and conflict risk with whatever you install next. On stores with a Lighthouse score below 60, replacing apps with native Liquid is usually the single highest-value build available, and it typically moves Lighthouse 30 to 50 points.
Our own tooling
We are a product company that also builds for clients
Webrex operates nine apps on the Shopify App Store, used by over 300,000 merchants. That is unusual for a development agency, and it changes the work.
We maintain production apps under real load, so app architecture is not theoretical for us
We know which Shopify APIs are stable and which will break on you, because ours have
We know the true cost of an app, which is why we tell you when not to build one
Anything our apps already do, you get. No licence fee, no rebuild
Webrex AI SEO Optimizer Schema
Webrex: SEO Audit Optimizer
SEO Schema & JSON‑LD
Webrex: SEO Speed Optimizer
Currency Converter
Webrex Multi Announcement Bar
WB: Frequently Bought Together
Webrex ‑ Pricing By Country
Webrex Google Shopping Feed
Most agencies offering Shopify app development have never shipped one to the App Store. We ship nine and support them daily.
View all apps
Our process
The Webrex Growth Framework
1
Phase 01
Discover
Catalogue, margins, bestsellers, customers and competitors. We audit the live store and read your analytics. You get a Discovery Brief before anything else happens.
2
Phase 02
Prioritise
Every gap labelled Critical, High, or Enhancement, ordered by revenue impact rather than by how easy it is to build. You approve the task list before we start.
3
Phase 03
Build
Two-week sprints. Daily updates. Staging preview on day 7, full delivery on day 14, then a review window. Approved work goes live immediately rather than waiting for a batch.
4
Phase 04
Launch and monitor
Redirects confirmed, 48 hours of monitoring on speed, indexing, and checkout. Loom training so your team can edit sections without a developer. 30 days of support included.
Timelines are commitments, not estimates: standard theme build 4 weeks, migration 6 weeks, Shopify Plus 8 weeks.
Proof, not promises
Real stores, real numbers
shopify plus
Ecommerce Inventory Management Done Right: Syncing Shared Stock Across Variants
Eeveve
·
Kids & Baby
subscription
Shopify Subscriptions: How We Built Multi-Product Plans Beyond the Native Limit
HeroLifeCare
·
Health & Medical
shopify flow
Shopify Restricted Products: How to Automate Customer Verification with Shopify Flow
Mountainside Medical
·
Health & Medical
Fit check
Is this a fit?
Most people who hire a Shopify developer are trying to solve one of two things: the platform will not do what they need, or the workaround they installed is now costing them money. Both are worth a call. Neither needs a rebuild by default.
Good fit if you
- Need something Shopify does not do out of the box, and have hit the wall with apps
- Are on Shopify Plus, or moving to it, and need checkout or B2B logic
- Have an operations problem that is eating hours every week
- Want the build scoped against a number rather than a feature list
Not a fit if you
- Want a theme recoloured, and content swapped. That is Theme Customization, and it costs a fraction of this
- Are migrating from another platform with no custom work attached. That is Shopify Migration
- Want a redesign for how it looks rather than what it earns. That is UI/UX Design
- Are looking for the cheapest quote. We will lose that one, and you will pay twice
If you are in the second list, say so on the call. We will point you to the right page, even if it is a cheaper one.
Straight answers
Common questions
01How long does a custom Shopify build take?
Standard custom theme: 4 weeks from approved wireframes. Complex builds with custom apps or Plus checkout extensions: 6 to 10 weeks. Migrations from WooCommerce or Magento: 6 to 8 weeks, including redirect mapping. These are commitments, not estimates.
02Do you do custom Shopify app development?
Yes, private and public. We operate nine apps on the Shopify App Store ourselves, so app architecture is something we maintain daily rather than something we read about. Private apps for internal tools and integrations, public apps if you want to sell one.
03Can you replace our apps with custom code to speed the store up?
Usually, it is the highest-value build available. We audit the stack, work out what can be native Liquid or Shopify Functions, and rebuild it. Typical Lighthouse improvement from app consolidation is 30 to 50 points.
04Do you work with Shopify Plus?
Yes. Checkout extensions, B2B catalogue logic, multi-store, Markets, and Functions. Worth knowing: Shopify Scripts are deprecated, so Plus stores still running them need a full reimplementation in Checkout Extensions, not a copy-paste.
05Can you customise our existing theme instead of rebuilding?
Yes. Section-level work, Liquid snippets, Metafield schemas, and app replacement do not need a rebuild. Minimum engagement is 2 weeks.
06What happens after launch?
30 days of support included at no extra cost. Bugs and missed requirements are fixed for free within the window. After that, ongoing retainers are available.
07Should I hire a Shopify developer or an agency?
A freelance developer is cheaper and fine for a defined task you can specify precisely. An agency is worth it when the job crosses disciplines, when the build needs to survive someone leaving, or when you want the work scoped against a revenue number rather than an hourly rate. If you already know exactly what needs building and it is one thing, hire a developer. If you are not sure what to build, that is the part we are actually selling.
08Are you UK-based?
We are in Ahmedabad, working UK and US hours, serving clients in both. Most collaboration happens in Slack and on a weekly call.