Legacy System Migration Services for Safe, Low-Risk Modernization

Legacy system migration services move aging applications, databases, and platforms onto modern, supportable technology with minimal disruption. The work spans assessment and planning, data migration, replatforming or reengineering, integration modernization, testing, cutover, and post-migration support, all designed to reduce technical debt and protect business continuity.

Migrate when annual maintenance consumes 60-70% of your IT budget, when the original vendor has ended support, when you cannot hire developers for the legacy stack (COBOL, VB6, classic ASP), when security vulnerabilities cannot be patched, or when the system blocks integration with modern tools. If three or more of these apply, migration should be a priority within 12 months.

The six Rs are rehost (lift and shift to modern infrastructure), replatform (move with targeted cloud optimizations), refactor (restructure code to reduce technical debt), rearchitect (reshape a monolith into modular or microservices design), rebuild (rewrite on a modern stack), and replace (retire the system in favor of a modern or SaaS product). We assess each application and recommend the path that best balances cost, risk, and long-term value.

Strangler fig migration incrementally replaces legacy components one module at a time while both systems run in parallel, reducing risk but extending the timeline to 6-18 months. Big bang migration replaces the entire system at once over a cutover weekend, which is faster but carries higher risk of downtime and data issues. We recommend strangler fig for mission-critical systems and big bang only for smaller, well-understood applications with comprehensive test coverage.

We use five key risk controls: parallel running (old and new systems side-by-side for 2-4 weeks), automated data validation with row-count and checksum verification, feature-flag-based rollback capability, comprehensive regression testing (typically 200-500 test cases), and phased user rollout starting with a pilot group of 10-20% of users before full cutover.

Our approach is designed for minimal downtime. By running the new system in parallel, syncing data with change data capture, and rehearsing the cutover before go-live, the actual switch is reduced to a short, controlled window, often outside business hours. For complex environments we use a phased rollout so most users continue working uninterrupted while groups are moved over in stages.

Yes. We assess each workload for cloud readiness across security, compliance, performance, and cost, then recommend the right target on AWS, Azure, or GCP. Depending on the application that may mean rehosting to virtual machines, replatforming onto managed services, or rearchitecting into containers, so you gain elasticity, resilience, and a predictable pay-for-use cost model.

We map every integration during discovery, then replace brittle point-to-point connections with documented APIs and middleware. During the parallel-run period both old and new integrations are validated so dependent systems, reporting, and partner platforms keep working. This integration modernization is planned alongside the migration rather than left as an afterthought.

Cost depends on system complexity, data volume, and integration points. A small application migration (single database, fewer than 50 screens) typically costs $50,000-$150,000. Mid-size ERP or CRM migrations run $200,000-$800,000. Enterprise-scale migrations with multiple interconnected systems range from $500,000 to $2M+. We provide detailed estimates after a 2-3 week discovery phase that maps all dependencies, data volumes, and business rules.

We follow a five-step process: data profiling to understand schemas and quality issues, cleansing rules to fix inconsistencies, ETL pipeline development (using tools like Azure Data Factory or Apache NiFi), iterative test migrations with automated validation reports, and final cutover with rollback scripts ready. For large databases (100GB+), we use change data capture (CDC) to sync delta changes during the parallel running period.

Legacy migration focuses on moving a system, its applications, data, and integrations, onto modern, supportable infrastructure with minimal change to behavior, often as a rehost or replatform. Legacy modernization goes further, refactoring or rearchitecting the application to remove technical debt and adopt patterns like microservices and cloud-native design. Most programs combine both: we migrate to a stable foundation first, then modernize where it delivers the most value. For deeper rework, see our application modernization services.

The greatest need is in data-intensive, regulated sectors where legacy systems are deeply embedded: government and public sector, banking and financial services, insurance, healthcare, manufacturing and logistics, and retail. These industries face the highest cost from downtime, data loss, and compliance gaps, which makes a risk-controlled, phased migration approach especially important.