Replatforming timelines in these interviews rise with what has to move alongside the storefront. Buyers describe storefront launch timelines ranging from a few weeks for straightforward SaaS migrations to one or two and a half years for projects involving major ERP changes, custom functionality or B2B requirements, and multi-market rollouts that extend across several years. The ranges overlap, and they describe reaching go-live, not necessarily finishing the stabilization and remaining functionality work that follows. Among buyers who gave both a plan and an outcome, none finished early, and most of those who hit their date did it by launching with less. Here are the seven reasons — the companion reads are what buyers wish they'd known before replatforming, where the ratings live, and why brands replatform.
The seven reasons they slip
Go-live is not the end of the project
The reason buyers raise most is what comes after launch. Several describe months of stabilization before the new site works the way they wanted — “This year was really a lot of stability in terms of that re-platform,” one says — and others describe living with bugs well into the first year: “as we've only launched after a year, so there are still some bugs and things that we're working through.” One buyer on an upgrade describes problems “that could go six to eight months post-launch, waiting on these vendors to update their extensions for the upgrade.” A plan that ends at launch day leaves this period unscheduled.
Named in this context: Shopify · commercetools · Salesforce Commerce Cloud · Magento
Custom features have to be rebuilt — or dropped to hold the date
Years on one platform leave behind functionality nobody lists until it has to be rebuilt. One buyer describes a team that had been on BigCommerce for years with “functionality that they built up that they're having to rebuild on the new platform.” When the date is fixed, the features give: “When we migrated over to Shopify, we were in such a hurry to do it, we didn't build that out,” one buyer says, and another, of a promotions feature, “We thought we could fix that for our launch and found out that we couldn't.” Loyalty enrollment, promotions and omnichannel features are the examples buyers give.
Named in this context: Shopify · BigCommerce · Salesforce Commerce Cloud
Back-office changes and integrations extend the project
The storefront is the visible part, but a replatform also needs its back-office connections to work. Some companies replace an ERP or order management system alongside the storefront, which makes it a larger transformation; others keep their existing systems but have to rebuild the integrations, map the data and check that inventory, orders and fulfillment information move correctly. “There was just all kinds of chaos with the NetSuite thing, and it took us a lot longer than we projected to get that going,” says one buyer who changed ERP and platform together. Others describe “a lot of integrations with Legacy internal systems. Those haven't been easy,” and the hours spent mapping data between the old system and the new: “You spend all of that time trying to map the data.” For subscription businesses, moving stored payment details is its own project.
Named in this context: NetSuite · SAP · Shopify · Optimizely
Every app, tag and tool has to be re-connected
A replatform moves the site out from under every tool attached to it. One buyer moving to a headless front end describes having to “redo all of the tags that Wunderkind had on site because we're moving headless,” and that “in the meantime, we didn't have any of our triggered emails going out.” Others describe a reviews tool down for a month or two during the move, and a year later still not having added a new vendor: “We just haven't been able to onboard a new vendor since our Shopify migration.” Search rankings move too — one buyer describes a 90 to 120 day hit to organic traffic after URLs changed.
Named in this context: Wunderkind · Shopify · Salesforce Commerce Cloud
The agency or integrator sets the pace
Many replatforms are built by an outside agency or systems integrator, and buyers describe several that cost them time. “We had a horrible SI before I started. We finally got a decent one. So it took us almost two and a half years to get the thing launched,” one says. Another describes an agency that “almost did more harm than they did good,” and a third is starting over after “a very bad implementation process with our third-party vendor.” Even a partner the platform vendor recommends is no guarantee, as one of the stories below shows.
Named in this context: Salesforce Commerce Cloud · Optimizely · BigCommerce
Markets, brands and B2B multiply the work
Each additional market, brand or buyer type adds rules the new platform has to handle. “All these countries have very highly nuanced business challenges and regulations, and we have to govern and abide by those,” one global buyer says. B2B sites are their own project — “a much bigger project than the B2C side,” in one buyer's words — and regulated categories add compliance questions. Multi-market companies describe rolling out a market or a site at a time, which is how a one-year build becomes a multi-year program.
Named in this context: Salesforce Commerce Cloud · commercetools · SAP Commerce · BigCommerce
Peak season sets the deadline — and the shortcuts
Holiday and peak trading periods shape many of the retail replatforming timelines in these interviews. Buyers push to launch before busy periods or defer major changes until afterward, often with code freezes and deadlines that force decisions about which features are essential for launch: “we are approaching Q4 and code freeze. So with the new site launching, we're not looking to touch the site for this short term.” The deadline is where scope gets cut — “They wanted to get it done before holidays, and a lot of the detail work wasn't complete,” one buyer says — and a launch that misses the window waits for the next one. One buyer has hoped to start the same move two years running and been held back each time by other priorities.
Named in this context: Shopify · Salesforce Commerce Cloud
Where do the ratings fit?
Implementation experience is one of several things behind each platform's rating, and the platforms in these timelines sit at very different points on the scale. The ratings themselves, and what buyers say drives them, are on what buyers wish they'd known before replatforming. What the timelines add is that the same platform can take weeks for one company and years for another, depending on what comes with it.
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The counter-current: the replatforms that held their date
The moves that came closest to plan share a shape. A global brand that phased its rollout expected a year — “We knew we'd be able to stand up the solution in a year” — and reached its first two markets in 13 months, with “the initial rollout has been smooth.” Others release one capability at a time rather than switching everything at once; one leadership team asked to “not do big bang changes, but rather do more incremental changes.” Brands moving to a SaaS platform with ready-made templates and apps describe the shortest builds, and afterwards faster work: “If earlier we were to launch a landing page within one week, now it's reduced to one day or two days.”
What this means for your replatforming timeline
In these interviews the length of a replatform is set by what moves with the storefront more than by the platform, and the slip comes from stabilization, custom features, the back office, the apps, the integrator, the number of markets and the holiday calendar. Our recommendations, not practices buyers describe: list every custom feature, integration and app the old site depends on before setting a date, and decide which can wait; count stabilization as part of the project and schedule it, rather than ending the plan at launch; ask who will build it, and how the integrator will be held to the date; phase markets, brands or capabilities where you can; and plan launch and stabilization around peak trading periods, leaving time to resolve critical issues with checkout, inventory, fulfillment and integrations before the busiest weeks, even if lower-priority optimization continues afterward. To see where buyers go when they move, read why brands replatform.
Common questions
How long does an ecommerce replatform take?
It depends on what moves with the storefront. In these interviews a single brand moving to a SaaS platform such as Shopify describes anything from a few weeks to about a year; a move that also changes the ERP, carries heavy custom code or serves B2B buyers takes from about nine months to two and a half years; and multi-market enterprises describe phased rollouts inside programs that can run for years. The ranges overlap and measure the time to go-live; most buyers describe months of stabilization after launch on top.
Why do ecommerce replatforming projects take longer than planned?
The recurring reasons in these interviews are stabilizing the site after go-live, rebuilding custom features the old platform had, integrating the ERP, order management and data, re-connecting apps and third-party tools, agencies and systems integrators that underdeliver, the complexity of multiple regions, brands or B2B, and peak-season deadlines that force a launch with less. Among buyers who gave both a plan and an outcome, none finished early.
Will sales drop after replatforming?
Some buyers describe a hit and some an improvement. In these interviews a few describe conversion or sales problems after launch — from missing features, configuration problems or a site no longer as optimized as before — and one plans to use the new platform to get back to baseline, while another reports conversion improvements after moving. None gives a figure for the size of a drop.
Does replatforming hurt SEO?
It can for a while. One buyer in these interviews describes changing URLs and losing search rankings for roughly 90 to 120 days after a move, and another names losing organic traffic as the biggest concern going into a migration. It is a smaller theme than integrations or stabilization, but buyers who raise it treat it as a real cost.
When is the best time to replatform an ecommerce site?
Buyers in these interviews plan launches around the holiday season: they push to go live before it and then freeze the site through it. The ones who launched just before peak describe shipping without features and stabilizing under the heaviest traffic of the year. Leaving time to resolve critical checkout, inventory, fulfillment and integration issues before the busiest weeks, even if lower-priority work continues afterward, is our recommendation, not a practice buyers describe.
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