Legacy Modernisation

Ageing systems brought forward without a rewrite freeze.

Legacy modernisation spans more than code — it's often an end-of-life data store nobody wants to touch (a Cassandra-to-PostgreSQL migration, for instance) sitting underneath a monolith nobody wants to touch either. We handle both: application-level strangler-fig decomposition and the underlying data store migration, sequenced so the business doesn't stop.

01  How we solve it

What this looks like in practice

01

An inventory of both layers that usually need modernising together — the application (an ageing Java monolith) and the data store underneath it (often an end-of-life or unsupported database).

02

Strangler-fig decomposition at the application layer, so the monolith keeps serving traffic while capabilities peel off, route by route.

03

Data store migration — including cross-technology moves like Cassandra to PostgreSQL — engineered as idempotent, resumable Apache Spark pipelines with row-level reconciliation.

04

Sequencing that respects your actual risk tolerance: which routes and datasets move first is a business decision as much as a technical one, and we plan it with you.

05

A rollback plan at every phase, so modernising never means betting the business on one big irreversible cutover.

02  Proof

Zero data-loss, at scale

Large-scale data migration with Apache Spark — 80% faster migration, zero data-loss incidents, on a repeatable, resumable pipeline. Read the case study →

03  FAQ

Legacy modernisation — frequently asked questions

How is this different from your Legacy Java Modernisation service page?
That page is about the application-layer mechanics — strangler-fig decomposition and Java version upgrades. This page is about legacy modernisation as it actually shows up across industries, which often includes the data layer too — an end-of-life database, not just an old application. In practice the two usually happen together.
What does a Cassandra-to-PostgreSQL migration involve?
Schema redesign (Cassandra's denormalised, query-first modelling doesn't map directly onto a relational schema), a custom-conversion Apache Spark pipeline to move the data, and row-level plus aggregate reconciliation so you have proof nothing was lost — not just a completion message.
Do we have to freeze feature work during modernisation?
No — that's the point of strangler-fig decomposition and phased data migration. The old system keeps serving traffic and the business keeps shipping while modernisation happens incrementally underneath it.

Talk to an architect about your legacy system.

Tell us what's ageing and what's actually at risk — we'll map the sequencing.

Talk to an architect