Shopify CRO Agency
HelloDevs finds where your Shopify store loses buyers and fixes it in code — tracking you can trust first, then product page, cart, checkout and speed changes, tested honestly for the traffic you actually have.
- Six years on Shopify
- Tracking audited before anything is tested
- Fixed quotes, not hourly guesses
Most conversion work starts with a button colour and a test nobody has the traffic to finish. HelloDevs starts with the data, the speed and the friction, and tells you plainly when a test would not tell you anything.
What kind of conversion work does your store need?
What kind of conversion work does your store need?
Conversion rate optimization is a loose label for very different jobs. Find the situation closest to yours, and the first piece of work follows from it.
| Your situation | What it usually calls for |
|---|---|
| Traffic is healthy but conversion has been flat for months | A baseline before anything else: confirm what is being measured, find the step where sessions actually drop, and only then decide what is worth changing. |
| GA4, Shopify and your ad platforms never agree on revenue | Attribution repair first. A test read from numbers that disagree proves nothing — see how we build reliable order and event data. |
| The store feels slow on mobile | Speed work: third-party app scripts, image delivery, theme JavaScript and layout shift, measured against real-user Core Web Vitals rather than a single lab score. |
| Your traffic is modest | Fewer, larger changes backed by session recordings, customer research and analytics, not a calendar of small A/B tests that would take a year to conclude. We will say so before you pay for a testing programme. |
| Shoppers reach checkout and leave | A look at what your plan lets you change there — checkout UI extensions and Functions, and what is Shopify Plus only — before promising anything about checkout. |
| Your theme has been patched so often that nobody wants to test on it | A cleanup of the sections that matter, a proper theme build, or a migration if the platform itself is the constraint. |
Six parts of Shopify conversion work
Conversion is the sum of measurement, speed, clarity and trust. HelloDevs scopes each part on its own, so you pay for the ones your store actually needs.
How A/B testing actually works on Shopify
How A/B testing actually works on Shopify
Shopify's architecture limits what you can test and how. Knowing the options up front stops a testing tool being sold to you for a page it cannot reach.
- Theme variantsDuplicate theme versions, or a template alternative, with visitors split between them. Good for layout and content changes on the storefront; cleanest when the split happens before the page renders, not after.
- Client-side testing toolsA script rewrites the page in the browser after it loads. Quick to set up, but it can flash the original version, add JavaScript weight, and quietly hurt the speed you are trying to improve. Fine for small copy tests; we are cautious about it elsewhere.
- Shopify Functions for offersDiscount, delivery-option and payment-method logic runs inside Shopify as a Function, and can be varied by a cart attribute or customer tag assigned to a test group. This is the reliable way to test an offer, because the price logic is applied on Shopify's side.
- Checkout extensibility limitscheckout.liquid is retired, so the old approach of injecting scripts into checkout no longer applies. Checkout is customised through checkout UI extensions, Functions and branding settings. UI extensions on the information, shipping and payment steps are Shopify Plus only; the Thank you and Order status pages are open to every plan.
- Server-side or edge splitsOn a headless or proxied storefront, the split is decided on the server before the page is sent, so there is no flicker and no extra client-side script. It needs a headless build to exist, so it is not a reason to go headless on its own.
- Not a test at allBefore-and-after measurement, qualitative research and fixing obvious defects are often better methods for lower-traffic stores. A fix that removes a real bug does not need a test to justify it.
What these terms actually mean
What these terms actually mean
CRO has a lot of vocabulary, and some of it is used to make weak results sound strong. This is what the terms mean, so you can read a report critically.
- Statistical significanceA measure of how unlikely your result would be if the change did nothing. It is not the probability that the variant is better, and it is meaningless if the test was stopped early or peeked at.
- Minimum detectable effectThe smallest uplift a test is able to detect given your traffic and baseline conversion rate. If the effect you are hoping for is smaller than this, the test cannot find it, whatever the dashboard says.
- Sample sizeHow many visitors or orders each variant needs before the result is trustworthy. It rises sharply as the expected effect shrinks and as baseline conversion falls, which is why many stores cannot run many tests.
- Sample ratio mismatchWhen the traffic split is not the split you configured — say, a variant is receiving noticeably fewer visitors than intended. It signals a tracking or assignment bug, and results from that test should not be trusted.
- Core Web VitalsGoogle's field-measured speed metrics: Largest Contentful Paint for loading, Interaction to Next Paint for responsiveness and Cumulative Layout Shift for visual stability. They are scored from real visitors, so a good lab score on one page does not guarantee a pass.
- Novelty effectA change that performs well simply because it is new, then fades. It is the main reason to run a test across full weekly cycles and to re-check a winning variant after it ships.
Where conversion programmes actually fail
- If purchase events fire twice or not at all, every result downstream is wrong. We audit the event layer before the first test and recheck it after every theme or app change.
- A store that does not have the traffic for a subtle change declares a winner anyway. The fix is to test bigger changes, test fewer things, or measure differently — not to run the test and trust the green tick.
- Checking daily and stopping on the first favourable reading inflates false positives. We set the duration and the stopping rule before launch and keep to them.
- Popups, review widgets and personalisation scripts each add weight and can cost more in lost patience than they earn. We measure each app's real cost before recommending another one, and audit what is installed as part of the work.
- What converts for another brand reflects its audience, price point and trust. We start from your own funnel data and your own customers' questions.
- Most Shopify traffic is on phones, and mobile conversion is usually where the largest gap is. We review and test on real devices, not only in a desktop browser's responsive mode.
If a CRO proposal does not mention your sample size,
it is selling testing you may not be able to complete. HelloDevs does that arithmetic first, before you commit to a programme.
What a Shopify CRO project includes
What every HelloDevs CRO quote covers
Every quote covers all of this. If a proposal leaves out any of it, the gap shows up later as a result nobody can trust.
- Funnel auditA ranked list of the problems found, with the data or recording behind each, so the priorities are arguable rather than assumed.
- Tracking baselineGA4, pixels and order data reconciled, with the discrepancies that were found and fixed documented.
- Speed reportField and lab Core Web Vitals, the apps and assets responsible, and what was changed.
- The changes themselvesImplemented in your theme, extensions or Functions, in your repository, reviewed on real devices.
- Test planHypothesis, primary metric, minimum detectable effect, duration and stopping rule, agreed before launch.
- An honest sample-size noteWhether your traffic supports testing at all, and which method we recommend if it does not.
- Results write-upWhat was tried, what happened, what is uncertain, and what to do next, including the tests that showed nothing.
- Source codeYours, in your repository, from the first commit.
- A handover your team can useDocumentation of what was changed and why, so a later developer or agency can pick it up.
How a Shopify CRO project runs
Five steps, with measurement fixed before anything is changed
You see the evidence behind every recommendation, and nothing ships without a way of knowing whether it helped.
- Problem callYou tell us what is not converting and what you have already tried. We tell you honestly whether the first job is measurement, speed, friction or testing.
- Fixed quoteA written scope, a timeline and a price for the audit and the first round of changes, not an open-ended retainer.
- Audit and baselineTracking verified, funnel analysed, speed measured. The ranked findings come back to you before any change is made.
- Build and testChanges shipped in small, reversible steps, tested where your traffic supports it and measured against the baseline where it does not.
- Review and decideA plain results write-up, and a recommendation on whether to continue, change direction or stop.
Shopify CRO tech stack
Engineering tools, not a testing-tool subscription
Included because technical buyers ask, and because a vague answer here usually means the work is a tool login rather than a change to your store.
The Conversion Stack
Liquid and theme sections for storefront changes, theme app extensions for anything installable, checkout UI extensions and Shopify Functions where your plan allows, web pixels and the customer events API for tracking, and field data from the Chrome User Experience Report alongside Lighthouse for speed.
- Liquid
- Theme App Extensions
- Shopify Functions
- Web Pixels
- GA4
- Core Web Vitals
- Lighthouse
- sections/main-product.liquid01
- extensions/checkout-ui/src/Checkout.tsx02
- extensions/web-pixel/src/index.ts03
- assets/theme.js04
Assign Once, Analyse by Group
A visitor is placed in a test group once, the group is stored, and every event carries it, so results are read from the same group the visitor actually saw.
const group = assign(visitorId, 'pdp-test');
track('pdp_view', { group });No Script Pile-Up
We do not stack a testing tool, a heatmap tool and a personalisation tool on a store that is already slow. Each script has to earn its weight.
another-widget.js
No Subcontracting
We do not subcontract. The people who audit the store are the people who change it.
MeasureChange
Shopify CRO questions
- It typically depends on four things: how much of the funnel is in scope, whether tracking needs repair first, how much of the work is code rather than analysis, and whether you want a one-off audit and fixes or ongoing testing. We quote a fixed price for a defined first phase once those are answered, and we do not promise uplift figures.
- It typically depends on your traffic. Fixing tracking, speed and obvious friction can show up within a normal reporting cycle. A formal A/B test needs enough visitors for each variant, which for many stores means several weeks per test, and some stores cannot reach a reliable result on small changes at all. We would rather tell you that up front.
- It depends on your baseline conversion rate and the size of change you hope to detect: smaller expected effects need far more visitors. We work out the minimum detectable effect for your store before proposing a test. If your traffic cannot support testing, we recommend before-and-after measurement, research and defect-fixing instead.
- Within limits. checkout.liquid is retired, so checkout is changed through checkout UI extensions, Shopify Functions and branding settings. Extensions on the information, shipping and payment steps are Shopify Plus only; the Thank you and Order status pages are open to every plan. Offer logic, such as discounts and delivery options, can be tested through Functions. See our Shopify Plus development page for the detail.
- Yes. It is often the best first step, because a slow page loses visitors before any message can persuade them. We work from Core Web Vitals field data where available, find the apps and assets responsible, and change the theme code and image delivery. Where a theme needs structural work, that links to theme development.
- Conversion work is about the traffic you already have. Getting more of it is a separate job, covered on our Shopify SEO and marketing page. The two share the same tracking baseline, so they are easiest to run together.
- Changes are made on a duplicate theme or a branch, reviewed, and published only when agreed, so your live store is never edited blind. Everything is in your repository, and anything we add can be reverted.
Tell us where shoppers drop off
Send the problem and your store URL. A developer at HelloDevs replies within one business day.
Project examples and buying guides
Review the work, compare your options and prepare a brief before choosing your next step.
- Shopify revenue attribution
Why order and event data has to be trustworthy before any test can be read.
- App performance and metafields
How data is stored and read affects storefront speed as much as the theme does.
- Customise or rebuild your theme?
Compare scope, performance and ownership before changing a theme you plan to test on.
- Shopify theme development
When the theme itself is what limits speed and the changes you can make.
Talk to us about Shopify CRO
Tell us where shoppers drop off
Send the problem and your store URL. A developer at HelloDevs replies within one business day.
