Rethinking Replatforming

“Choosing the right commerce platform is critical. But nobody wants to spend a million dollars every few years to meet new business needs.” That’s how one tech executive at a multi-billion-dollar retailer described his team's dilemma before moving forward with a strangler-pattern migration using Broadleaf Commerce.

Many enterprise teams find themselves trapped between a monolithic platform that is too slow to evolve and a re-platforming strategy that feels too risky, too expensive, or too disruptive to pursue all at once.

The strangler pattern offers a different path. It’s not about a complete reset. It’s about shifting control back to engineering and architecture teams by isolating critical feature sets, replacing them incrementally, and running new and legacy systems side by side.

Coined by Martin Fowler, the pattern was named after the strangler fig tree, which wraps itself around a host, growing steadily until it replaces it. In software, the metaphor applies to how modern services can surround and eventually replace legacy systems without a single cutover event or “big bang” migration.

In the context of eCommerce, this strategy is more than metaphorical. It’s becoming an operational reality for retailers under pressure to scale, adapt, and innovate faster than traditional architectures allow.

Is the Monolith Actually Your Friend?

Legacy platforms are often profoundly entangled with business processes. Complex integration workflows, years of customizations, and engrained data management habits that were built over time still deliver real business value. But they typically result in mounting technical debt, team inefficiencies, performance, and security issues.

One Broadleaf client experienced session corruption due to the underlying architecture’s limitations. Customers who logged in from multiple devices at once, a common behavior, would trigger data collisions in their Java-based session management system. Their promotions engine was inflexible, making routine marketing campaigns slow and costly. And as the business grew internationally, deployment limitations meant each new region introduced risk to all others.

What they needed wasn’t a new frontend or a shiny new stack. They needed to disentangle the parts of the system that slowed them down and replace them with services that could move independently.

The challenge was not recognizing the problem but finding a migration strategy that wouldn’t halt their business in the process.

How does the Strangler Pattern Work in Real Life?

The strength of the strangler pattern is in its practicality. It accepts that most organizations don’t have the luxury of pausing development or freezing feature delivery for 12 to 24 months. It embraces parallel paths where new services are built in isolation and introduced gradually.

In the client’s case, Broadleaf was first used to modernize the promotions engine. Instead of retrofitting new offer types into a brittle legacy codebase, they replaced the promotions functionality entirely. In under four months, their teams launched a new API-driven engine with support for advanced promotions and zero downtime. This rollout was faster than it would have taken to patch the old system and immediately gave the marketing team new tools to drive revenue.

Once promotions were live, other services followed. Cart, checkout, and account modules were implemented in parallel, each owned by a different development track. Because Broadleaf’s architecture allows for service-level deployment and domain-based APIs, each capability could evolve on its timeline without impacting the rest of the stack.

This wasn't a front-to-back replatform. It was a service-based evolution strategy. The client’s front end was already decoupled. What they needed was composability at the backend, where real differentiation happens in pricing logic, checkout flows, and account data.

This is where the strangler pattern excels: in high-stakes environments with real-world complexity. It allows teams to iterate safely, move fast, and measure success one service at a time.

Why Broadleaf Was Built for This

Broadleaf's architecture supports the strangler approach not as a workaround, but as a primary mode of adoption. The platform is built around independently deployable services that can be integrated with or run alongside legacy or third-party systems. Every service, from pricing to promotions to cart to customer, is API-native and versioned for long-term compatibility.

Migrating any Commerce services, like a promotions engine, is not just about writing new business logic. Teams must design routing and request-handling logic that can simultaneously serve legacy and modern components, often using API gateways or orchestration layers. State consistency becomes critical, especially when data is written in both systems during the transition. Without robust CI/CD pipelines, rollback plans, and service observability, even a tiny service swap can introduce production risk. The strangler pattern must be paired with real architectural maturity, not just a roadmap.

Modular commerce is only helpful if it’s orchestrated well. In a composable environment, promotions, pricing, and checkout don’t just run independently; they rely on synchronized communication, coordinated releases, and shared data flows. Broadleaf’s architecture enables modular service rollout and supports the orchestration patterns required to unify them across the customer experience. That distinction, modular with orchestration, is what makes real-world composability achievable.

Some teams conflate the strangler pattern with a wholesale shift to hundreds of microservices. However, the proliferation of microservices comes with its own operational cost. Broadleaf supports a modular architecture that allows teams to own services like pricing or cart independently, without forcing ultra-fine-grained decomposition. This way, enterprises can preserve developer focus, minimize service sprawl, and still deliver modern API-first capabilities.

Perhaps most importantly, the platform is built on widely adopted tech. Using Spring Boot and a modern Java stack, Broadleaf is easy for enterprise developers to embrace and extend with a commercial open source model, enabling faster application development where developers can be ramped up in days, not months.

Final Thoughts

The strangler pattern has moved from an interesting theory to a proven model for digital commerce transformation. It enables engineering leaders to phase out technical debt without incurring operational debt, and it allows businesses to respond to change without waiting for an all-or-nothing go-live event.

The strangler pattern is more than a safe bet for commerce teams navigating complex customer journeys, business-critical SLAs, and global deployments. It’s a strategic advantage.

Broadleaf helps enterprises take this approach in real-world conditions, supporting the kind of flexibility, interoperability, and composable control modern commerce demands.

You don’t need to rebuild everything at once. You just need to start replacing the parts that are holding you back.