Application Modernisation

Why Modernise Legacy Applications?

The case for modernising applications is compelling. Legacy systems often present increasing operational costs, as they require more effort to maintain and secure. They tend to lack the flexibility needed to scale with demand and can act as blockers when integrating new tools or responding to shifting customer expectations.

For many organisations, these limitations slow down innovation, introduce compliance concerns, and put them at a disadvantage against more agile competitors. Modernising applications with containers and orchestrators, for instance, opens up new possibilities for performance, scalability, and resilience.

Modernisation Approaches that Fit Your Business

Every application landscape is different, which is why D55 tailors its approach to suit both technical complexity and business goals. Some systems can be rehosted (lift-and-shift), moving the application to AWS with minimal changes. Others require replatforming to optimise for cloud readiness or refactoring to redesign application architecture at the code level. In some cases, rebuilding or replacing a system is the most efficient path forward.

Our team assesses where you are on your modernisation journey and helps you choose the path that delivers the most value

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The Business Impact of Modernisation

When done right, application modernisation delivers tangible outcomes. You’ll see a marked reduction in technical debt and operational costs, while improving scalability and system performance. Agile release cycles allow you to adapt faster to market needs, while the underlying infrastructure becomes easier to manage and secure.

Better user experience, streamlined integrations, and compliance-ready architectures become standard. With enhanced governance, security, and visibility, your systems will be future-ready and resilient by design.

Technology That Powers Modernisation

Modern application development depends on a robust toolkit. AWS provides a rich ecosystem of tools and services that support this transformation. With cloud-native capabilities such as containers and serverless computing, applications can be broken into modular components, improving agility and resilience.

Microservice-based architecture, supported by AWS tools like ECS (Elastic Container Service) and Lambda, allows applications to scale independently and deploy features faster. Using APIs, we integrate systems seamlessly across the business. CI/CD pipelines, supported by AWS CodePipeline, ensure code is shipped with confidence. Data can also be modernised through AWS services like Aurora, enabling real-time analytics and improved governance.

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Why AWS?

AWS is a recognised leader in cloud computing and digital transformation. With purpose-built services, a robust global infrastructure, and proven frameworks, AWS makes it easier for businesses to modernise with confidence. Tools like App Runner simplify deployment, while managed services reduce the overhead on your teams.

D55 is experienced in delivering AWS cloud consulting solutions that support rapid transformation, whether you're moving one critical application or an entire estate. As experts in both cloud strategy and hands-on engineering, we bridge the gap between technical implementation and business value.

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Ready to Begin?

The journey towards modernising your applications starts with a conversation. Whether you’re exploring rehosting, replatforming, or redesigning your architecture entirely, our team can help you assess readiness and plan your modernisation strategy.

Explore how our Microservice design capabilities support cloud-native architectures, or discover more about our experience in Architecture redesign projects.

Download our latest modernisation guide, or book a discovery session to uncover the best way to modernise your applications on AWS.

Solving problems and supporting innovation

Real-World Success Stories

Our notable area of specialism is the energy sector, where we have deep domain knowledge. However, the commonality of the challenges means that frequently work across diverse industries, including for private equity backed growth businesses, and would love to talk to you about how D55 can redefine how you think about modernisation.

Take a look at our collection of case studies showcasing the transformative impact of partnering with D55 and AWS.

All case studies

AWS Optimisation and Licensing Assessment

AWS Migration Acceleration Program

AWS Modernisation Viability Assessment

AWS Well-Architected Review

Application Modernisation