Legacy Modernization

Turn legacy systems into AI-ready platforms without downtime

AI cannot act on a system it cannot reach. We re-architect, migrate and support legacy platforms in increments, so the business keeps operating and AI agents get clean APIs, data and permissions to work with.

Legacy modernization is our service for keeping ageing systems in production while re-architecting, migrating and exposing them through modern APIs. We use AI-assisted analysis and code migration to shorten the work and finish by making the system agent-ready. It is for CTOs and operations leaders whose core platforms limit what AI can do.

uptime for a Fortune 500 supply chain platform we re-architected to microservices
99.999%
supporting and evolving that platform, with 40+ carriers integrated
10+ years
print shops running an ERP we modernized from a decade-old POS system
25
IBM to AWS migration for a SaaS serving 3,500+ brands
Zero downtime
The problem

Why legacy is where AI stalls

MIT NANDA found that 95% of generative AI pilots show no P&L impact, and Gartner expects 40% of agentic AI projects to be cancelled by 2027. Across the 2026 studies the root causes repeat: data readiness, integration with legacy systems, missing governance and skills. In logistics, 65% of operators say they are stuck in ad-hoc experimentation because legacy TMS and WMS systems limit deployment.

The systems are not bad. They are the business. An order platform built a decade ago encodes rules nobody has written down, feeds downstream systems through nightly files and cannot be paused for a rewrite. A big-bang replacement risks the operation; doing nothing means every new AI initiative starts by scraping screens.

Modernization has changed. LLM-assisted code analysis, test generation and language migration remove much of the manual translation that made these projects multi-year. The hard part remains judgment: what to keep, what to strangle, in what order, and how to prove nothing broke.

What we do

Capabilities

Technology assessment and modernization strategy

A clear plan for migrating off outdated platforms safely, and a reason for every step.

  • Audit of source code, architecture, databases, security and portability
  • Evaluation from four angles: UX, technical state, business fit, maintainability
  • Options compared: rehost, replatform, refactor, re-architect, replace
  • Roadmap with increments, dependencies and cost per phase
  • Risk register and rollback plan per increment

Re-architecture and reengineering

Monolith to services without a rewrite, using the strangler pattern and stable interfaces.

  • Microservices split along business capabilities, one service at a time
  • REST APIs in front of existing modules so new frontends ship first
  • Containerization with Docker and Kubernetes
  • Fault isolation so one failing service does not take the platform down
  • New features delivered while the old platform is still supported

AI-accelerated code and language migration

LLM tooling does the reading and the first draft. Engineers own the review.

  • LLM-assisted comprehension and documentation of undocumented systems
  • Translation of COBOL, legacy Java, GWT or older .NET to modern stacks, reviewed line by line
  • Generated test suites that pin behavior before and after migration
  • Batch migration of large codebases with human review gates
  • Verified, not trusted: every migrated module passes the pinned tests

Legacy data migration

Data integrity first, then speed. Historical data becomes usable for analytics and AI.

  • Data profiling: duplicates, inconsistencies and dead records removed first
  • Schema conversion, including heterogeneous moves such as IBM DB2 to PostgreSQL
  • Replication with cutover measured in minutes of lag
  • Validation rules and reconciliation reports
  • Historical data preserved and queryable on the new platform

Cloud migration and infrastructure

On-premises or mainframe to AWS, Azure or Google Cloud, with the infrastructure defined as code.

  • Target platform chosen for the workload, including hybrid when some data must stay on-site
  • Infrastructure as code with Terraform from the first environment
  • Right-sized compute with a cost model before the move
  • Security, logging and backup configured as part of the migration
  • Post-migration optimization and monitoring

Agent-ready integration layer

The interfaces that let AI agents work with the system instead of around it.

  • Stable, documented APIs over legacy functions that agents can call
  • Event streams from legacy transactions for real-time automation
  • Scoped service identities and permissions for agents
  • Adapters for EDI, SOAP and file-based interfaces
  • Audit logging of every agent action against the legacy system

Legacy system support

For systems that are staying: keep them performing, secure and understood.

  • Ongoing maintenance and bug fixing
  • Security patching and dependency upgrades
  • Performance monitoring and incident response
  • UX/UI refresh without changing the backend
  • Knowledge capture so the system no longer depends on one person
In production

How it runs in production

Modernization is measured by what did not break. These practices keep it that way.

01

Incremental cutover

Functions move one at a time behind a stable interface. The old path stays available until the new one has run clean in production, and traffic can be routed back in minutes.

02

Behavior pinning

Automated tests, generated from real transactions where documentation is missing, define what the system does before we change it. Every increment must pass them.

03

Parallel run and reconciliation

For data and financial flows, old and new run side by side and their outputs are reconciled until they match. Discrepancies are investigated, not tolerated.

04

Observability and support

Monitoring, alerting and on-call cover both the legacy and the modernized parts. Support continues after the last increment; 89% of clients stay longer than 12 months.

Proof

What we have built

All case studies

How it works

How we work with you

  1. 01

    Diagnose

    A full assessment of the legacy estate: code, architecture, data, infrastructure, security and the people who know it. Output: a ranked list of constraints and a modernization roadmap that protects existing investment.

  2. 02

    Optimize the architecture

    Before new technology, we refine what exists: reduce technical debt, define the target architecture and mark the seams where the system will be split. Your technical stakeholders sign off the plan.

  3. 03

    Modernize in increments

    Each increment is scoped, tested against pinned behavior and released with rollback ready. AI-assisted tooling speeds the translation; engineers own the review. First results within 2 weeks.

  4. 04

    Evolve continuously

    Performance monitoring, operational insight and adjustments after each release. The modernized system becomes the platform for the next automation and AI work.

Stack

Technologies we build with

Platforms we have migrated from

  • Java EE and WildFly
  • GWT and Errai
  • IBM DB2
  • Salesforce and other no-code platforms
  • Monolithic on-premises systems
  • COBOL and mainframe

Target platforms

  • Java and Spring
  • Node.js and TypeScript
  • Python
  • React and Angular
  • PostgreSQL
  • Microservices on AWS
  • Docker and Kubernetes

Migration and modernization tooling

  • AWS Schema Conversion Tool
  • AWS DMS
  • Terraform
  • LLM-assisted code analysis and migration
  • Automated test generation
  • Cypress and Selenium

Integration

  • REST
  • GraphQL
  • Kafka
  • EDI, SOAP and XML adapters
  • Keycloak
FAQ

Legacy Modernization: questions we get asked

What is legacy software modernization?

Updating software that still runs the business but has become expensive, fragile or impossible to extend. It ranges from moving an application to the cloud unchanged, to replacing the database or language, to re-architecting a monolith into services, to a full rebuild. The goal is not newer technology for its own sake but lower maintenance cost, reliability, and the ability to integrate new capabilities, including AI, without risking the operation.

What approaches are used in legacy system modernization?

Rehost (move as-is to new infrastructure), replatform (change the runtime or database with minimal code change), refactor (restructure code without changing behavior), re-architect (split into services or change the architecture), and replace (rebuild or buy). Most programs combine them: rehost first to stop the bleeding, then refactor and re-architect the parts that block the business. The assessment tells you which combination fits which module.

How long does a typical modernization project take?

A single application replatformed to the cloud can take a few months. Re-architecting a core platform is a program of one to several years, delivered in increments that each go to production. The supply chain platform we re-architected to microservices has been evolving for 10+ years with 99.999% uptime; a decade-old POS system became an ERP for 25 print shops over a longer engagement. AI-assisted migration shortens the translation work substantially, but the schedule is set by verification, not by typing speed.

What risks are associated with legacy system modernization?

Undocumented behavior that breaks when it is changed, data loss or corruption during migration, integrations that fail silently, a team without expertise in the old technology, extended parallel maintenance of two systems, and a big-bang cutover that cannot be reversed. We manage them with behavior-pinning tests, profiled and reconciled data migration, incremental cutover with rollback, and support that covers both systems until the old one is retired.

Can all legacy applications be modernized?

Technically, yes; economically, not always. If the business logic is sound and the cost is in the platform, modernize. If the application no longer fits the process it was built for, replacing it, sometimes with an off-the-shelf product, is cheaper. If it works, is stable and is not blocking anything, supporting it as-is can be the right decision. The assessment answers this per application with numbers, and we will say so when modernization is not worth it.

What does it mean to make a legacy system agent-ready?

An AI agent needs three things a legacy system usually lacks: a stable API it can call instead of a screen, an identity with scoped permissions so it can only do what it should, and an audit trail of what it did. Agent-ready modernization adds those in front of the existing system, often before any deeper re-architecture, so automation and AI work can start while the modernization program continues underneath.

Find out what your legacy system can become

A 45-minute discovery call. Bring the system everyone is afraid to touch; we will tell you what to keep, what to change and in what order.

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