Legacy System Modernisation in London

We build the new system in parallel to the old one, then choreograph a cutover that's tested multiple times in a staging environment that mirrors production. Data moves in stages using replication and dual-write patterns, so the old system keeps running until we verify the new one is sound. If anything breaks, we roll back immediately. High-transaction systems (fintech, payments) need this discipline. We don't flip a switch and hope.

It depends on codebase size and risk appetite. A small monolith with clear boundaries might take 3-6 months. A large, tangled system at a regulated firm could span 12-18 months in phases. We prefer phased delivery so you get early wins (a faster checkout service, a decoupled reporting system) while the longer refactor runs. This keeps momentum and lets you prove the business case.

Yes. Modernisation usually means moving from on-premise servers or older cloud setups to containerized, managed services. We help you choose the right platform (AWS, Azure, GCP) based on your current vendor lock-in and feature needs. We then handle Kubernetes setup, networking, observability, and CI/CD pipelines. Infrastructure is part of the refactor, not separate.

Your engineers stay on the project. We pair with your best architects and senior developers to ensure knowledge transfer and maintain decision quality. Juniors get hands-on mentoring from our delivery team. By the end, your team owns the new system, not us. We train and document so you can operate and extend it independently.

Cost depends on codebase complexity, team size, timeline, and scope (some migrations include cloud infra, others don't). We start with a discovery phase to give you a concrete estimate. Nearshore delivery helps control costs because we get depth at a different cost base than London hiring, but we never compete on price alone. We care about sustainable, maintainable outcomes.

Post-launch, we offer retainer-based app support and maintenance to monitor performance, patch bugs, apply security updates, and optimize under load. Many teams also use this time to add minor features or tune architecture based on real-world usage. We stay involved so you're not on your own the moment the new system goes live.