Shopify Theme Development
HelloDevs builds custom Shopify themes and rebuilds the ones that have stopped working. Clean Liquid, fast pages, edits your team can make without us.
- Six years on Shopify
- Liquid, Online Store 2.0, Horizon
- Fixed quotes, not hourly guesses
A theme is not a design. It is the thing your team fights with every week. HelloDevs builds themes that stop the fighting.
Do you need a custom theme?
Do you need a custom theme?
Most stores do not. A premium theme, customised properly, beats a bad custom build every time. Send the store URL before the brief — HelloDevs will tell you which row you are in, and sometimes the answer costs a fraction of what you expected.
| Your situation | What you probably need |
|---|---|
| Launching, budget matters, brand is simple | A premium theme, set up and customised. |
| Premium theme works, but three or four things are wrong | Shopify theme customization. |
| Your store is slow and you do not know why | A speed audit first, then decide. |
| Your brand needs a layout no theme sells | A custom Shopify theme. |
| You sell something unusual — configurators, bundles, made-to-order | A custom Shopify theme. |
| You have outgrown a theme patched by five developers | A rebuild, not another patch. |
| Your team cannot change anything without calling a developer | A rebuild on Online Store 2.0 or Horizon. |
Three kinds of Shopify theme development
“Theme work” covers three very different jobs. HelloDevs does all three, and the difference decides your budget and timeline.
Dawn or Horizon: which foundation
Dawn or Horizon: which foundation
Shopify launched Horizon in 2025 and made it the default for new stores. HelloDevs builds on both, and the choice matters more than most agencies admit.
- What changedHorizon is built on nested theme blocks — blocks inside blocks, up to eight levels deep. Dawn and other Online Store 2.0 themes stop at two. In practice that means layouts your team can build in the editor instead of paying for a custom section every time. Horizon also ships with roughly 28 sections against Dawn's 17, and includes AI block generation.
- The part nobody mentionsThere is no migration tool. Dawn and Horizon store content differently, so moving between them is a manual rebuild, not a switch — anyone quoting you a quick migration has not done one. AI block generation is real but partial: it handles simple blocks well and struggles with complex ones. Treat it as a scaffold, not a finished section.
- What we recommendNew store, or redesigning anyway: build on Horizon — the editor alone will save your team hours every month. Existing store on Dawn that works: stay. Dawn still ships, still gets updates, and still runs fine in 2026. Legacy theme from before Online Store 2.0: move — that decision was already overdue.
How a maintainable Shopify theme is built
How a maintainable Shopify theme is built
A theme your team can live with is decided in its structure, not its design. These are the parts we get right first — and the parts to ask any theme developer about.
- LiquidShopify's server-side templating. Everything a customer sees before checkout is rendered here first; JavaScript is added only where the page genuinely needs to react.
- Online Store 2.0 and JSON templatesPages are JSON templates that list sections, so a template for a product type or a landing page is something your team edits in the theme editor — not a condition hardcoded in Liquid.
- Sections and blocksSections are what the editor moves around; blocks are the pieces inside them. Settings with sensible defaults are the difference between a theme your team edits and one they avoid.
- MetafieldsStructured data on products, collections and pages — size charts, ingredients, care notes — connected to sections in the editor instead of pasted into descriptions. Metafields or metaobjects?
- MetaobjectsContent types Shopify does not have — store locations, lookbooks, designer profiles — defined once and reused anywhere in the theme.
- App blocks and app embedsWhere apps render without editing theme code. A theme built for them keeps apps removable; a theme where apps pasted code into Liquid collects dead scripts. Why that costs you speed.
- PerformanceResponsive images, deferred scripts, fewer font weights and an audit of third-party tags — measured on a mid-range phone on a slow connection, before and after.
- AccessibilityKeyboard navigation, visible focus, colour contrast and reduced motion, built in from the first section rather than bolted on at the end.
- MigrationVintage themes to Online Store 2.0, premium themes to custom, one foundation to another — templates, content and URLs mapped so nothing disappears in the move.
- Customisation or rebuildA customisation turns into a rebuild when every change breaks something else. We read the code and tell you which one you have before quoting.
What actually makes a Shopify store slow
- Each one can leave scripts behind after removal. This is the most common single cause and the easiest to fix.
- A 4MB hero resized in CSS is still a 4MB download.
- Third-party tags loaded before anything visible appears.
- Pulled in for one carousel on one page, then paid for on every page.
- When two would do.
- The cost of a template built for everyone.
Every agency promises fast pages.
Almost none say what they are actually removing. HelloDevs tests on a mid-range Android phone on a slow connection, because that is where your customers actually are — a speed number on a desktop connection means little.
What a Shopify theme project includes
What every HelloDevs theme quote covers
Every HelloDevs quote covers all of this. If an agency leaves any of it out, the cost reappears later as a change request.
- Scoping documentPages, sections and features agreed before any code is written.
- The theme itselfBuilt on Online Store 2.0 or Horizon, clean Liquid, no dead code.
- Sections your team can useConfigurable in the editor, not hardcoded.
- Responsive across real devicesTested on phones, not just resized in a browser.
- A speed pass before launchWith before-and-after numbers, not a promise.
- Accessibility basicsKeyboard navigation, contrast, alt text structure.
- DocumentationHow to edit every section, written for your team.
- Theme filesYours, in your repository, from day one.
- 30 days of post-launch fixesIncluded, not billed.
How a theme build runs
Five steps, and a preview URL every week
No hourly estimate that grows, and no big reveal at the end standing in for progress. You change your mind early and it costs nothing.
- Store reviewWe look at what you have and tell you whether you need a rebuild, a customisation, or a speed pass. Often it is the smallest of the three.
- Fixed quoteA written scope, a timeline, and a price. Not an hourly estimate that grows.
- Build in weekly cyclesYou see the theme on a preview URL every week, not at the end. Change your mind early and it costs nothing.
- Test and launchReal devices, real connection speeds, then a launch window that suits your traffic rather than ours.
- SupportThirty days of fixes are included. After that, a maintenance retainer if you want one, and no lock-in if you do not.
Shopify theme development tech stack
Pure-play Shopify developers
We develop only for Shopify. No bloated frameworks, no visual page builders that degrade site performance, and no subcontracting. Just clean, hand-crafted code.
The Theme Stack
Included because technical buyers ask, and because a vague answer here usually means the agency subcontracts the work. Liquid, Online Store 2.0, Horizon theme blocks, JSON templates, metaobjects, theme app extensions, the Storefront API, and Shopify CLI for local development and version control.
- Liquid
- Online Store 2.0
- Horizon
- JSON Templates
- Metaobjects
- Storefront API
- Shopify CLI
- sections/product-grid.liquid01
- blocks/price-badge.liquid02
- templates/product.json03
- assets/theme.js04
No Framework Needed
Vanilla JavaScript by default, CSS without a framework unless there is a reason, and a build step only where it earns its place.
document
.querySelector('[data-cart-count]')
.textContent = count;No Page Builder Apps
We do not use page builder apps to fake a custom theme. They slow the store down and lock you into a subscription to keep your own layout.
page-builder-app.zip
No Subcontracting
We do not subcontract. The people on the scope call are the people writing the code.
Store reviewLaunch
Shopify theme development questions
- A custom Shopify theme usually takes six to twelve weeks; a customisation of an existing theme takes one to four. A rebuild of a heavily patched store sits in between, and the review comes first because that estimate depends entirely on what previous developers left behind.
- Start with a premium theme unless your brand or your products genuinely need something no theme sells. A well-customised premium theme beats a rushed custom build, costs a fraction, and launches sooner. HelloDevs will tell you which one you need before you commit to either.
- Only if you are redesigning anyway, or if you are on a legacy theme from before Online Store 2.0. There is no migration tool between Dawn and Horizon — the two store content differently, so moving is a manual rebuild. Dawn still ships with new stores and still receives updates.
- Usually yes, and it is the first thing we check. Leftover scripts from removed apps, oversized images and render-blocking tags account for most slow Shopify stores, and none of those need a new theme. Speed and conversion work beyond the theme is covered under Shopify CRO.
- Yes — that is the point. Every section is configurable in the Shopify editor rather than hardcoded, and you get documentation covering each one. If your team needs a developer to change a heading, the theme was built wrong.
- Not any more, if they are built properly. Modern apps add storefront features through theme app extensions — app blocks and app embeds you place in the theme editor — so removing an app removes its code too. We build themes that expect this, and flag apps that still inject scripts.
- Yes, completely. The theme lives in your repository from the first commit, not ours. If you stop working with HelloDevs, nothing about your store depends on us.
- Often yes, but we read the code first and tell you honestly whether continuing is worth it, or a rebuild is faster. Sometimes it is a rebuild. You get that answer before you pay us anything.
- That is a different job from a client build, with its own review process and requirements. Talk to us about it — HelloDevs publishes its own Shopify products, so the submission process is familiar territory.
- Yes — for ongoing section work, performance passes or a steady stream of changes, a retainer usually fits better than a project. See hire a Shopify theme developer. See also Shopify maintenance and support.
Send us your store
A store URL tells us more than a brief does. A developer at HelloDevs will look at it and reply with an honest assessment — including if the answer is a small fix rather than a rebuild — usually within one business day.
Project examples and buying guides
Review the work, compare your options and prepare a brief before choosing your next step.
- Hello Studio: a section marketplace
Explore the design and implementation of our Shopify sections product.
- Hello Studio's marketing website
See how the product's website explains the offer and presents the sections.
- Customise or rebuild your theme?
Compare scope, merchant editing, performance and ownership before choosing a build.
- Theme or headless storefront?
Review the trade-offs before choosing a different storefront architecture.
Get a quote for your Shopify theme
Send us your store
A store URL tells us more than a brief does. A developer at HelloDevs will look at it and reply with an honest assessment — including if the answer is a small fix rather than a rebuild — usually within one business day.
