The systems holding you back are usually the ones you cannot afford to touch.

The platform is brittle, underdocumented, and expensive to maintain - but it is also in production, processing real transactions every hour of the day. Replacing it wholesale is too risky. Waiting is also a risk. The answer is neither big-bang replacement nor indefinite postponement. It is a disciplined, incremental migration that shrinks the old system one capability at a time while the business runs without interruption.

Gradion has done this in regulated fintech, multi-brand e-commerce, and cooperative retail networks - environments where the stakes were high and the documentation was either missing or wrong. Every engagement starts from the same principle: understand the system before you move it.

How We Migrate

Discovery as a technical deliverable Most legacy modernization projects fail in the first phase because the team underestimates what they do not know. We treat discovery as a deliverable, not a preliminary step. We map data flows, identify hidden dependencies, document undocumented business logic, and produce a written system inventory before any architecture decisions are made. If the documentation is missing, we reverse-engineer the system directly. If the documentation exists, we verify it - because in legacy environments, it is frequently wrong.

Platform selection and vendor evaluation. When modernization requires moving to a new platform - ERP, e-commerce, CMS, or operational system - the selection decision carries long-term consequences. We run structured evaluations against your specific requirements: functional fit, integration complexity, total cost of ownership, vendor viability, and exit risk. The evaluation is vendor-neutral. We do not resell platforms and we do not earn referral fees. The recommendation reflects what fits your business, documented with the trade-offs so you can defend the decision.

Strangler fig migration New capabilities are built as independent services alongside the legacy core. Traffic routes to the new service once it is validated. The old component is retired only when the new one is proven. Applied correctly, the monolith shrinks incrementally and the business never experiences a cutover event. We apply this pattern at the service level, the API level, and the data layer - adapting the granularity to the risk profile of each component. High-risk, high-frequency paths get the most conservative migration path.

Service extraction from monoliths Not every function in a monolith deserves its own microservice. The first decision is what to extract and in what order. We start with the boundaries that cause the most pain: the modules that block deployments, generate the most incidents, or prevent the business from adding features. We extract those into independently deployable services with clean API contracts. The rest of the monolith continues to operate, unmodified, until the next extraction cycle. This delivers value in weeks rather than years and keeps the architecture decision reversible.

Data reconciliation and state migration Data is usually the hardest part of any legacy migration. Years of accumulation mean duplicate records, inconsistent formats, undocumented conventions, and fields that mean different things in different contexts. We run reconciliation before migration, validate parity between old and new systems during parallel operation, and do not cut over until the data state is confirmed clean.

Compliance-first re-architecture In regulated environments, modernization is also a compliance event. Architecture choices must satisfy audit readiness, security hardening, and regulatory alignment - not just performance and maintainability. We design compliance into the architecture from the start. That is what makes aggressive timelines possible in regulated contexts: the compliance work is not bolted on at the end.

Proof in Production

Europe’s largest retail trade cooperative - reverse-engineering a live cooperative platform. The cooperative's platform supports hundreds of independent retailers in the European footwear and fashion industry. Gradion entered with no documentation, no system walkthrough, and a live system that could not be taken down. What appeared to be a straightforward rebuild turned out to be a system with hard-coded logic, invisible cross-dependencies, and product data mismatches causing customer-facing errors. We mapped every component through direct investigation, reconciled the data issues during stabilization, and produced a documented architecture plan as the foundation for modernization. The cautious approach - understand first, change second - prevented two potential production incidents during the analysis phase alone.

Multi-Brand E-commerce Operator - OXID to Shopware across three storefronts. The multi-brand e-commerce operator runs B2B and B2C e-commerce across three storefronts: Foxshirts, Textil-Grosshandel, and Lepona. The OXID platform had accumulated years of patches and duplicated plugin logic. Gradion delivered the Shopware migration with a unified plugin architecture and a storefront redesign. The result: 70% reduction in redundant development work and measurable performance improvement. The migration was completed without service interruption to active customers. For DACH e-commerce operators still running OXID, this migration path is more complex than it appears when storefronts have years of custom logic embedded in their plugin layer. We have delivered it without disruption.

Swiss credit platform - FINMA re-architecture in eight weeks. A Swiss provider of digital credit solutions had operated its core lifecycle software for over a decade. Tightening FINMA regulations and rising maintenance cost made continuation on the old architecture untenable. Gradion re-architected the system from the ground up in eight weeks with a team of three: a technical advisor, a PM/PO, and an AI engineer. Compliance, security hardening, and audit readiness were built into every layer from day one.

How We Work

Engagements begin with a scoped analysis phase - typically two weeks - producing a system inventory, risk assessment, and migration plan. We share what we find, including what we do not yet know and what requires further investigation.

Migration execution follows in structured phases, each with explicit go/no-go criteria. Every phase delivers a working increment. The old system shrinks. The new system proves itself in production before the next phase begins.

Working with your existing team. Your engineers know the system's history better than anyone. We work alongside them through discovery and execution. The migration plan reflects their capacity and knowledge. The goal is a path they can sustain - not a plan that depends on Gradion being present indefinitely.

When the plan changes. Legacy migrations surface surprises. Undocumented dependencies, data quality issues, production incidents that force reprioritization. The migration plan includes decision points designed for exactly this. We adjust scope, sequence, and timeline at each phase boundary based on what execution has revealed.

Engagement Structure

Discovery Workshop 3–10 days. A senior-led audit of your legacy systems, dependencies, and migration risk. We require access to the production environment (read-only where necessary), existing documentation, and working sessions with the engineers who maintain the system. The output is a system inventory, a prioritized modernization roadmap with cost and effort estimates per component, and a clear recommendation on migration approach. Scoped as a fixed-fee engagement.

Realignment Project 3+ months. Gradion works alongside your team to execute migration in structured phases. This means embedded engineers delivering working increments - extracting services, migrating data, retiring legacy components - with governed milestones and no disruption to live operations. Typical migrations run 3–9 months depending on system complexity and the number of interdependent components. Scoped based on team composition and phase structure.

Retained Advisory For organizations executing migration with their own team who want Gradion available for architectural decisions, risk review, and independent assessment of progress. A named principal maintains continuity with your system and migration plan. Particularly effective after a Discovery Workshop when your internal team leads execution but wants external oversight on critical migration steps.