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Engineering

Retire the risk without betting the business.

We modernize banking cores, ERPs and twenty-year-old monoliths without big-bang rewrites, using strangler-fig migrations that keep the business running.

Overview

Full rewrites of legacy systems fail so often that the pattern is well known. A system that looks easy to replace on a diagram holds twenty years of edge cases, regulatory workarounds and undocumented integrations, and the rewrite team finds each one in production. We do not bet your company on a single cutover day. Every modernization we run is a series of small steps, each one small enough to check and roll back.

We start by studying the old system, not by designing the new one. Before we suggest a target state, we instrument the existing system, map its real data flows and hidden users, and wrap its behavior in characterization tests. You cannot safely change what you cannot yet describe. This phase often turns up integrations nobody remembered and load patterns nobody expected, which is why our wave plans hold up in the real world.

Reconciliation keeps everything honest. During every wave the old and new systems run side by side, and an automated check proves every day, record by record, that they agree. Cutover is not decided in a meeting. It happens when the data passes the threshold. This is how we migrated a bank's ledger with zero settlement discrepancies, and it is the standard we hold for systems where failures cost real money.

Capabilities

How we study, migrate and retire a legacy system without stopping the business that runs on it.

System archaeology

We instrument and analyze the running system to map real data flows, hidden users and load patterns, before anyone suggests a target architecture.

Strangler-fig migration

Functionality moves to the new platform in small waves that each deliver value on their own, while the legacy system keeps serving everything that has not moved yet.

Data migration and reconciliation

CDC-based sync with automated record-level reconciliation for the whole time both systems run. We prove that they agree instead of assuming it.

Characterization test harnesses

We capture the legacy system's behavior as automated tests, so the new system can prove it does the same thing, including the edge cases nobody documented.

Zero-downtime cutovers

Traffic moves gradually behind a routing layer, with a rehearsed rollback at every step. Cutover weekends are replaced by cutover thresholds.

Compliance continuity

Audit trails, retention rules and regulatory reporting stay intact through every wave, with evidence packages ready for your auditors and regulators.

Process

No black boxes. Each phase has explicit outputs, and you see progress weekly, in staging, not slide decks.

  1. 01

    Audit and instrumentation

    Four to six weeks inside the existing system: mapping dependencies, tracing data flows, and writing characterization tests around the behavior that must survive the migration.

    Outputs

    • Dependency map
    • Data-flow traces
    • Characterization tests
  2. 02

    Target architecture and wave plan

    A modern target state and, more importantly, the ordered list of reversible waves that gets you there. Each wave has clear entry criteria, exit criteria and a rollback path.

    Outputs

    • Target architecture
    • Wave plan
    • Rollback paths
  3. 03

    First slice in parallel run

    A low-risk area moves first and runs in parallel with the legacy system. Automated reconciliation proves they agree before any cutover.

    Outputs

    • Parallel-run setup
    • Reconciliation reports
    • Cutover decision
  4. 04

    Wave-by-wave migration

    The remaining areas move at a steady pace. The new platform emulates the legacy interfaces, so the systems that depend on them can migrate on their own schedule.

    Outputs

    • Migrated domains
    • Emulated legacy interfaces
    • Wave retrospectives
  5. 05

    Decommission and handover

    We retire the legacy systems one by one and track the contract and license savings. Your team is trained to own the platform that replaced them.

    Outputs

    • Decommission log
    • Savings tracker
    • Team training
Outcomes

The results this service is accountable for, the reasons clients keep the engagement running.

Business as usual

The business keeps running through the whole migration, with no freeze.

Reversible by design

Every wave can be rolled back, so the worst case at any point is a rollback, not an outage.

Audit-ready evidence

Record-level reconciliation gives auditors and regulators proof, not promises.

No forced migrations

Systems that depend on the old one keep working against the emulated legacy interfaces and move when they are ready.

Lower run costs

Costs usually fall by 30 to 40% once mainframe or legacy licensing is retired.

Faster delivery

Teams ship weekly on the new platform while the old one winds down.

Stack

Chosen for your constraints, not our comfort, this is the toolkit we know deeply for this kind of work.

Languages
  • Java
  • Kotlin
  • COBOL
Backend & workflow
  • .NET
Data & streaming
  • Debezium
  • Apache Kafka
  • PostgreSQL
Cloud & infrastructure
  • Kubernetes
  • Terraform
Delivery & observability
  • SonarQube
FAQ

How we approach legacy projects: timelines, risk, regulation and pricing.