Building digital systems
Mortar's System Design practice brings together technical architecture, data engineering, and strategic planning to help organisations build digital systems that are robust, maintainable, and fit for purpose. Whether you are starting from scratch, modernising a legacy platform, or integrating new capabilities into an existing ecosystem, we provide the architectural thinking and hands-on expertise to deliver systems that work at scale.
A pragmatic, evidence-led approach
Technical discovery
Audit your existing systems, data flows, and infrastructure to identify constraints, risks, and opportunities for improvement.
Architecture design
Define a clear system architecture that meets your functional and non-functional requirements, including scalability, security, and maintainability.
API and integration design
Specify how your systems will communicate — internally and with external services — using modern, standards-based approaches.
Delivery and implementation support
Work alongside your development teams to translate architectural designs into working systems, with clear documentation and quality standards throughout.
Full-breadth technical architecture
Technical discovery and audit
We begin with a thorough assessment of your current systems, identifying technical debt, integration gaps, and areas of risk — giving us a clear baseline from which to plan and design.
Scalable architecture design
We design systems built to grow — using cloud-native patterns, microservices, and event-driven architectures where appropriate, prioritising resilience, fault tolerance, and operational simplicity.
API design and integration strategy
We design clean, well-documented APIs that make your systems easy to integrate and extend — applying RESTful and GraphQL patterns, and advising on standards such as the NHS Login API or GOV.UK Pay where relevant.
Data architecture
We design the data layer of your systems with care — defining schemas, storage strategies, and data flows that support both operational needs and analytical use cases.
Security and compliance by design
Security is embedded in our architectural process, not bolted on at the end. We design systems that meet the requirements of Cyber Essentials, GDPR, and sector-specific standards from the outset.
Technical documentation and handover
We produce clear, maintainable architectural documentation — including system diagrams, data dictionaries, and decision logs — so your teams have everything they need to operate and evolve the system.
The case for system design
Eliminating the cost of technical debt
Poorly designed systems are one of the biggest drags on public sector productivity. Fragmented data, brittle integrations, and systems that cannot adapt to changing needs create enormous operational costs and limit an organisation's ability to deliver better services.
Enabling better data use
When systems are designed with data quality and accessibility in mind, organisations gain the insight they need to improve services, demonstrate impact, and make evidence-based decisions.