Shopify Plus CRO agency: how to choose CRO services

A good Shopify Plus CRO agency uses what Plus unlocks and proves every change with a test. On Plus, that means testing the information, shipping, and payment steps of checkout, building offers with custom Shopify Functions, and judging each test on revenue per visitor over full weeks. The top Shopify CRO agencies share a few traits: they build and QA the variants themselves, they know checkout extensibility, they report revenue for every test, and their pricing makes clear who carries the cost of losing tests.

What Shopify Plus changes for CRO

Most CRO work looks the same on any Shopify plan. Product pages, collections, and the cart are all theme code. Plus adds three things a CRO partner should use.

Checkout. Only Plus stores can use apps that customize the information, shipping, and payment steps of checkout [Shopify]. On other plans, those steps are largely closed to customization. On Plus, trust messages, delivery information, and upsells inside checkout all become testable.

Custom Functions. Shopify Functions let developers change how discounts, bundles, and delivery or payment options behave. Any plan can use public apps that contain Functions, but only Plus stores can use custom apps built on them [Shopify]. That opens up offer tests a stock app can't run, like a tiered discount built around your margins.

Market targeting. Shopify's Rollouts tool can target a specific market or region only on the Advanced and Plus plans [Shopify]. A store selling in several countries can run a change in one market before it goes everywhere.

One Plus detail separates current partners from outdated ones. Shopify retired checkout.liquid for the in-checkout pages on August 13, 2024, and replaced it with checkout extensibility [Shopify]. An agency still pitching checkout.liquid tweaks is selling work that no longer runs.

What Shopify Plus CRO services should include

The scope varies between providers, but a complete service covers these steps:

1. Audit. A review of where shoppers drop out, using Shopify's funnel reports, session recordings, and support questions.
2. Research. Turning each drop-off into a hypothesis worth the traffic.
3. Design and build. Variants built in your theme, checkout extensions, or Functions, with no work handed back to your developers.
4. QA. Every variant checked on phones, with discount codes, Shop Pay, and each currency and market you sell in.
5. Testing. A 50/50 split against the live store, run for full weeks, with the traffic split checked throughout.
6. Analysis. Each result judged on revenue per visitor, with winners shipped and losers switched off.

If a proposal stops at step 2, it's a consultancy deck. You'll still need someone to build and run the tests.

What the top Shopify CRO agencies have in common

Before trusting any list of top Shopify CRO agencies, check who published it, since some are written by an agency that ranks itself first. Judge providers on evidence instead. The strong ones share these traits:

• They show tested results. Case studies name the metric, the test length, and the size of the lift, and they describe losing tests as well as winners.
• They build the tests themselves. Your team approves changes. It doesn't write code.
• They measure revenue. Every test reports revenue per visitor for each group, with conversion rate as a supporting number.
• They protect test quality. They run full weekly cycles, avoid stopping early, and check that the split stays close to 50/50, since a sample ratio mismatch usually invalidates a test [Fabijan et al., 2019].
• Their proof is real. Testimonials and logos come from actual clients. In the US, fake and AI-written reviews and undisclosed insider reviews are now banned [FTC, 2024], so ask for a client you can speak to.

Questions to ask a Shopify Plus CRO agency

• Which checkout tests have you run on checkout extensibility? Ask for examples on the information, shipping, or payment steps.
• Can you build custom Functions? If not, your offer tests are limited to what public apps can do.
• What gets added to our store? Ask which apps or scripts go on, how they affect page speed, and how they come off when the work ends.
• What decides a win? Look for revenue per visitor, a confidence threshold, and a minimum test length in full weeks.
• Who owns the winning code? Winners should stay on your store after the engagement ends.
• What happens to a losing test? It should be switched off quickly and cost you as little as possible.

How Shopify Plus CRO services are priced

You'll see three models: hourly, monthly retainers, and pay for performance. The right one depends on who carries the risk of losing tests, and most tests lose. At Microsoft, about a third of tested ideas improved the metric they targeted, a third made no difference, and a third made it worse [Kohavi et al., 2009].

Under hourly or retainer pricing, you pay for the losers. Under a performance model, the provider only earns when a test produces a verified revenue lift. The DIY vs agency guide compares the models in more detail, including when running tests in-house makes more sense.

Where Cascayd fits

Cascayd is a performance CRO service for Shopify and Shopify Plus stores. It runs the audit, builds and QAs every variant with no dev work from your team, tests each change 50/50 against your live store, and judges it on revenue per visitor. Only verified winners count toward fees, there is no setup fee or retainer, and there is no promise of a specific lift. See how the Shopify CRO service works, or start with a free Shopify CRO audit.