The Retailer’s Guide to Legacy to Digital Transformation (+ Examples)

According to McKinsey, 9 out of 10 organizations are currently undergoing some form of digital transformation. Which raises an obvious question: What's the other one doing?

If they’re working to maintain a legacy system, that costs an average of $40,000 every year—and that’s just the baseline for keeping the lights on. The real tax is in labor and opportunity cost: IT workers report losing an average of 17 hours per week maintaining aging platforms, which is less time to work on advancing new initiatives. 

According to IMD, moving away from legacy technologies is one of today’s defining digital transformation strategies. 

We’ll walk you through what it means to go from legacy to digital in retail, with success stories from commerce teams who’ve been there.

What is a legacy system in ecommerce?

A legacy system is an outdated system, not necessarily in terms of age, but whether it costs more to maintain than it returns in value—in speed, stability, or in the customer experiences it can support. 

A system built five years ago can already be legacy, and a system built 15 years ago might still be doing its job.

In commerce, legacy status tends to show up in four recognizable patterns:

1. A platform so bespoke that only the people who built it understand it, and half of them have left.
2. An on-premises or self-hosted setup that requires your team to own infrastructure that a cloud provider could manage at lower cost with stronger security.
3. A web of point-to-point connections between systems that technically works until one thread gets pulled and the whole thing unspools.
4. Fragmented data spread across enterprise resource planning (ERP), product information management (PIM), an order management system (OMS), and your store point of sale (POS), none of which are speaking the same language.

Some of these systems don’t appear broken at first glance, but that’s the trap. They function, just not at the speed modern commerce demands.

Why is it important to modernize legacy systems in 2026?

McKinsey has a name for today’s shopper: “zero consumer.” These consumers have zero loyalty when a competitor makes things even slightly easier, and zero patience for the gap between what they experience online and what they find in-store.

Recent research finds that 65% of retailers’ current store technology can’t deliver the kind of experience today’s customers expect. Old, fragmented systems can prevent you from offering the smooth shopping experience customers expect, but it also hinders your ability to compete effectively in modern retail.

In a recent blog, Shopify Senior Engineer Patrick Joyce calls these compounding inefficiencies the “fragmentation tax,” and the bill arrives in four installments: 

1. Technical overhead: Every system needs its own maintenance, its own updates, and its own person watching it.
2. Operational friction: Data that lives in separate systems. Someone has to reconcile it manually, often slowly and with plenty of room for error.
3. Business drag: New features take months to ship, so by the time a change has touched every system, the market has moved on—and so have your customers.
4. Innovation deficit: The developers who should be building what’s next are busy fixing what’s breaking.

Before switching to Shopify, luxury jewellery brand Mejuri was contending with the difficulties of a legacy system.

“When you start looking under the hood, we were spending most of our time in building and maintaining third-party integrations, which come out of the box with a unified solution like Shopify,” says Rohit Nathany, chief digital officer at Mejuri.

For Mejuri, the shift to Shopify’s unified commerce model took less than nine months. Rohit called that timeline “insanely fast,” and the result was a fundamental reorientation of how the team spends its time. 

What are the pros and cons of legacy system transformations?

There are real benefits to replacing a legacy system. . But ripping out and replacing your entire stack is a complex operation that can’t be done overnight.

Let’s look at the pros and cons. 

The benefits of replacing legacy systems

You can move fast

Peter Sheppard Footwear has been around for over 40 years, with a deeply loyal customer base and stores in Sydney, Melbourne, and Brisbane. But on their legacy platform, even a simple update took 24 hours. After migrating to Shopify, they tripled their conversion rate and grew online revenue 30% season-on-season.

Your operations work in tandem

Fragmented systems create fragmented data, and fragmented data creates work. Nutrition Warehouse had 120 locations across Australia and New Zealand running on Adobe Commerce for ecommerce and a separate POS system that required full-day staff training sessions. After migrating to Shopify and Shopify POS, all 120 stores were onboarded in six months; staff training dropped from a full day to 15 minutes; and time spent on data consolidation fell 15%.

You start capturing more revenue

The family-run legacy shoe brand Giesswein started on Adobe Commerce. At first, the platform worked. But what it didn’t do was let the team grow. When they migrated to Shopify, average yearly sales grew 179%, and the brand expanded to five international stores in 12 languages and eight currencies—with zero downtime during peak sales periods. 

Shopify is the ultimate platform to grow our business at lightning speed. The ease of use and the potential for scale are magnificent as we do not need to spend as much time on technical operations.

The disadvantages of replacing legacy systems

• You might face migration downtime. Downtime during peak trading periods often means lost sales and customers who don’t always come back. The risk is real enough that most teams either delay migration indefinitely or rush it badly, and both outcomes cost more than the migration itself.
• Your data integrity could take a hit. Product data, customer records, and order history are the institutional memory of your business. But the truth is that bad data going into a migration doesn’t get cleaner on the other side. It gets harder to find.
• Your costs may spiral past the original estimate. The full scope of custom integrations, data cleanup, and edge cases only becomes visible once work has started.

Skullcandy, however, went in with both eyes open. Before migrating to Shopify, the headphone brand was running an aging, heavily customized stack. 

Mark Hopkins, Skullcandy's CIO, said that the team was spending too much time “making sure that things were flowing” rather than innovating.

They set an aggressive 90-day target, and thirty days in, end-to-end test orders were already flowing into their ERP. On launch day, Jenny Buchar, director of global digital experience, said: “We were waiting for the other shoe to drop, and it just didn't.” 

Within weeks, Skullcandy had launched in Canada, the EU, and the UK by reusing the patterns Shopify made repeatable. Checkout went from five steps to one, product launches that used to take a full day now take under an hour, and their first full holiday season on Shopify delivered 45% year-over-year revenue growth—their strongest period ever.

For our biggest product launch of the year, we saw a 200% increase in site visits and zero performance issues.

📚Read more: Avoid Digital Transformation Failure: 7 Mistakes Enterprise Commerce Leaders Make

Four approaches to go from legacy to digital transformation 

These four approaches range from the least disruptive to the most complex.

Replatforming

You move the core engine to a modern cloud environment or a software-as-a-service (SaaS) provider, but you keep the underlying business logic and ERP connections exactly as they are.

This is the fastest way to get off your legacy system. That said, if you’re not careful with your choice of ecommerce platform, you'll upgrade the interface, but still risk running on the same 10 years of broken integration debt.

Refactoring and re-architecting 

In Queensland rainforests, strangler figs grow by wrapping themselves around an existing tree—slowly, over years—until the original tree is gone and the fig is standing on its own. 

Martin Fowler borrowed this image to describe what’s now called the Strangler Fig Pattern: a way of migrating away from a monolithic system by incrementally replacing it, piece by piece, while the original keeps running underneath.

You identify specific functions, like your three-warehouse inventory logic, and rewrite them as independent microservices. You stay on the old system while slowly migrating functionality into a new, decoupled architecture.

Replacing and integrating

Here, you swap your commerce core but keep the systems around it. You're replacing the main commerce platform while keeping ERP, OMS, or other back-office systems in place. 

You first solve the back]end complexity by introducing a middleware or integration-platform-as-a-service (iPaaS) layer. You have to funnel all your integrations into one source of truth first, and once the back end is tidy, the digital transformation of the storefront becomes much more plug-and-play. 

Keep in mind, however, that this delays the visible transformation—the user interface—while you fix the plumbing.

Headless or composable commerce 

This approach decouples the front end from the back end entirely. Your storefront and your back end become independent, connected via APIs but free to evolve separately. You can swap out any component without rebuilding the whole system.

This is high stakes, but it may be the best way to truly shed 10 years of technical debt in one go, like Westwing did. The European home and living brand had spent a decade building out a bespoke ecommerce platform in-house. The system was deeply customized and had become a major obstacle in the way of expanding into new markets. 

So they ripped and replaced their entire commerce stack and moved to Shopify. On Shopify, they built a headless architecture that gave them a strong back end without sacrificing their branded storefront. They adapted Shopify Checkout to make the migration invisible to customers and built a single-store model they could replicate in every new market.

“We decided to move to Shopify as we believe it provides us with the most future-proof way to think about commerce,” says Usama Dar, CTO.

Westwing shows what’s possible with a clean break, but your path depends on how much weight your current system is carrying. 

Use this logic to see if you should follow their lead or take a more incremental route:

1. Do you have a hard deadline (e.g., license expiry) in less than months?
• Yes: Replatform; move as-is to buy time.
• No: Continue.
2. Are your integrations hardwired into the core database?
• No: Go headless.
• Yes: Continue.
3. Can your regional warehouses survive a dark period during cutover?
• Yes: Replace and integrate.
• No: Choose the Strangler Fig Pattern.

If you answered no to the last question, that’s not surprising. For most enterprises, the Westwing way is too high-risk because of the sheer density of existing integrations. 

The Strangler Fig Pattern is a helpful alternative, because it gives you the same modern end-state as a headless build, but without the “big bang” risk.

Gartner research highlights that a large proportion of digital initiatives struggle to meet their outcomes, and industry guidance increasingly favors incremental modernization patterns, like the Strangler Fig Pattern, because they limit risk exposure and allow quality lessons to inform each release cycle. 

An 18-month roadmap for successful digital transformation

The Strangler Fig Pattern works in phases: as the old system gets smaller, the new one gets stronger. 

Days 1–90: Stop the bleeding

In this stage you establish a shared, uncompromised picture of your current state.

1. Map everything that speaks to your commerce core: Who talks to what, how, and how often? ERP? OMS? Inventory feeds? Tax engines? Payment gateways? Shipping partners? Create a simple dependency map. 
2. Assign clear ownership to each node in your dependency map: Change management is a critical part of digital transformation in commerce. For every integration or system identified, name one stakeholder who is responsible for operational stability, data accuracy, and post-migration success criteria.
3. Make sure you can see what’s happening: If you’re evaluating a modern commerce backbone like Shopify, this is where you pressure-test:
• Can it serve as a clean order system of record?
• Can it give unified reporting across online and POS?
• Do its APIs make data extraction structured and predictable instead of script-based?
4. Start automating the operational glue: Even while your legacy core stays in place, you can launch low-risk automation that cuts manual toil right away:
• Explore Shopify’s API documentation to understand how your existing systems could talk to a modern commerce layer.
• Use Shopify Flow to codify repeat tasks you’re patching manually.

You're on track if: Every integration touching your commerce core is documented, and you can trace your last three incidents back to a root cause.

Months 3–6: Pick your first fig

In this stage, you’re replacing one high-impact function that breaks most often or blocks growth.

1. Choose the right function: For most commerce brands, this is checkout or inventory logic. Checkout because every second of friction costs revenue, and inventory because bad stock data ripples through warehouses and returns.
2. Isolate and replace that function: Rewrite it as an independent service while the legacy system keeps running everything else. Do not shut down the monolith. Do not migrate everything at once. 
• If checkout is the problem, this is where a standardized layer like Shopify Checkout can remove custom payment scripts, tax patches, and brittle discount logic in one move.
• If inventory is the issue, consolidating stock management under a unified layer like Shopify’s inventory system, including real-time sync across online and Shopify POS, can eliminate parallel inventory truths.

Establish a clear before-and-after baseline tied to the function you’re replacing.

If it’s checkout, measure your checkout conversion rate, payment failure rate, and incident volume. If it’s inventory, monitor your oversell rate, manual stock adjustments, and reconciliation time. 

You're on track if: The function you replaced is generating fewer incidents and fewer manual interventions, and your checkout conversion rate is moving in the right direction.

Months 6–18: The old system runs out of things to do

You've decoupled one service, kept the business running, and ensured your team is comfortable with the new process. Now you repeat it, systematically, in order of impact.

• Prioritize the next cuts: Rank remaining functions by impact and fragility. Move the ones that either generate revenue or generate incidents—modernize in order of consequence.
• Shrink the monolith intentionally: More commerce logic should live outside the legacy system than inside it after a year or so. 
• Standardize the new foundation: As your back end stabilizes, you can start building on it instead of just replacing pieces. If you’re using Shopify as your commerce backbone:
• Shopify supports expanded API access and higher API rate limits, letting integrations with ERP/OMS run reliably even under high traffic.
• Shopify’s Storefront API delivers commerce-critical primitives like products, carts, customer accounts, pricing, and localized data that you can consume from any front end. 
• You can build custom, high-performance storefronts with Hydrogen.

You're on track if: Time-to-ship has dropped, support ticket volume is down quarter on quarter, and new capabilities are going live faster.