APPLICATION MODERNISATION SERVICES
Application modernisation across your portfolio
We plan application modernisation around business value and technical constraints, then replace or improve legacy components in controlled increments.
- A path chosen per application, not one approach forced on the estate
- Incremental delivery, so value ships every phase
- No big-bang cutover: every migration reversible by slice
There is no universally right approach. Each path trades effort against payoff.
The correct choice depends on the system's business value, technical debt, and target.
Most estates need a mix. The output of our assessment is a path per application, sequenced so the highest-value, lowest-risk moves go first. Where the estate is large, this pairs with [Application Portfolio Rationalization](/application-portfolio-rationalization) to decide what to modernise at all.
Forcing one approach across an estate is the most common reason modernisation programmes run over. The right answer is a path per application.
Value first, cutover never. Retire the legacy system only when its replacement has earned it.
The strangler-fig pattern: no all-or-nothing cutover.
A big-bang rewrite asks you to switch over on a single terrifying date.
Instead, you wrap the legacy system, route slices of functionality to new services one at a time, and let the old system shrink until it can be safely removed. Value ships every phase and risk stays small.
Facade
Put a routing layer in front of the legacy system.
New and old coexist; traffic is controllable.
Carve
Extract the first high-value capability into a new service.
First slice modernised, in production, reversible.
Redirect
Route that capability to the new service, monitor closely.
Real traffic proves the new path before the next slice.
Repeat
Carve and redirect further capabilities in priority order.
The legacy footprint shrinks with every increment.
Retire
Decommission the legacy system once it is fully strangled.
Old system gone, no big-bang cutover, no frozen roadmap.
A closed, reversible loop
Every migration is a governed slice you can roll back.
Risk stays small; value ships continuously.
Application modernisation in controlled increments.
Assess
Each system: business value, technical health, dependencies, and target.
Decide
The path per application and sequence the roadmap by value and risk.
Wrap
The legacy estate with a facade, so modernisation can be incremental.
Carve and ship
Capabilities into cloud-native services, one governed slice at a time.
Retire
Legacy components as they are strangled, then hand over to your team or an embedded pod.
Modernised services deploy onto the platform built by Cloud Infrastructure and ship through your DevSecOps pipeline, so they inherit the golden path from day one.
The rest of the Cloud and Platform Engineering practice.
Application Portfolio Rationalization
Decide what to modernise at all before choosing how, across a large estate.
FOUNDATIONCloud Infrastructure
The cloud-native platform modernised services land on from day one.
DELIVERYDevSecOps
The golden path every carved slice ships through, secure by default.
SECURITYCloud Security
Zero-trust controls that new services inherit as the legacy footprint shrinks.
BUILDProduct and Platform Development
The teams that build the new cloud-native services carved out of the monolith.
PILLARCloud and Platform Engineering
The parent practice this service belongs to.
What engineering leaders ask us first.
No, and you should not. The right answer is a path per application. Forcing one approach across an estate is the most common reason modernisation programmes run over.
Sometimes, when maintenance cost has overtaken value and no incremental path exists. But it is the exception, and even then we prefer to replace incrementally where the architecture allows.
Modernised services deploy onto the platform built by Cloud Infrastructure and ship through your DevSecOps pipeline, so they inherit the golden path from day one.
Modernise your legacy systems one step at a time.
A path per application, sequenced by value and risk, delivered one reversible slice at a time.