EXPERTISE / ENGINEERING

.NET application engineering and modernisation.

Cloud-native APIs, distributed services and web applications on modern .NET — designed for resilience, observability and long-term maintainability, and incremental modernisation of legacy .NET Framework estates.

What we deliver

Design and implementation of .NET applications and services, from greenfield builds to the incremental modernisation of established codebases.

Engineering quality is a business concern

Code that is hard to change slows every future initiative. We write clear, tested, observable .NET code and help teams adopt practices that keep it that way — without gold-plating.

Modern .NET in practice

We build on current long-term-support releases and use the platform's strengths rather than fighting them.

• ASP.NET Core minimal APIs and controllers with OpenAPI contracts and versioning
• Blazor for rich web front ends in C#; Azure Functions isolated worker for event-driven work
• Resilience with retries, timeouts and circuit breakers; health checks and graceful shutdown
• Observability with OpenTelemetry traces, metrics and structured logging
• .NET Aspire for local orchestration of distributed applications where it helps

Architecture patterns

We apply patterns where they solve a real problem, not by default.

• Modular monolith first, with clear domain boundaries (domain-driven design) that can be extracted into services when scale or ownership demands it
• Clean, vertical-slice or hexagonal architecture to isolate business rules from frameworks and infrastructure
• CQRS where read and write models genuinely diverge; outbox pattern for reliable event publication
• API gateways and reverse proxies with YARP; gRPC for low-latency internal service calls
• Background processing with hosted services, Azure Functions or Service Bus consumers with idempotent handlers

Performance and resilience engineering

We measure before optimising and design for degraded dependencies.

• Load and soak testing with k6 or Azure Load Testing against agreed latency percentiles (p95/p99)
• Profiling with dotnet-trace, dotnet-counters and BenchmarkDotNet
• Resilience pipelines with Microsoft.Extensions.Resilience (Polly): timeouts, retries with jitter, circuit breakers and bulkheads
• Caching strategies with output caching, HybridCache and Azure Cache for Redis
• Native AOT and trimming where start-up time and memory footprint matter

Upgrading from .NET Framework

Legacy .NET Framework applications can usually be moved forward incrementally. We assess dependencies, use the .NET Upgrade Assistant and API analysers, and apply a strangler-fig approach — routing functionality to new services piece by piece — so the business keeps running throughout.

Testing that earns its keep

We favour fast unit tests around business rules, integration tests against real dependencies with Testcontainers, consumer-driven contract tests for service boundaries, and a thin layer of Playwright end-to-end tests for critical journeys. Mutation testing (Stryker.NET) is used selectively to verify that tests actually detect defects. Everything runs in CI on every pull request.

Problems we address

• Legacy .NET Framework applications that are costly to run and risky to change
• APIs and services with unclear contracts and fragile dependencies
• Low test coverage that makes every release a gamble
• Performance or reliability problems under real load

Technologies and approaches

• C# and .NET 10
• ASP.NET Core and minimal APIs
• Blazor
• Azure Functions (isolated worker)
• Entity Framework Core
• .NET Aspire
• OpenTelemetry
• xUnit, Testcontainers and Playwright

Typical engagement activities

• Codebase and architecture assessment
• Modernisation strategy (strangler-fig, incremental upgrade)
• API and service design
• Implementation alongside your engineers
• Test automation and performance profiling

Deliverables

• Working, tested software in your repositories
• API contracts and architecture documentation
• Automated test suites and CI integration
• Upgrade and modernisation roadmap
• Engineering guidelines tailored to your team

Potential business outcomes

• Faster, safer releases
• Lower maintenance and hosting costs
• Codebases that new engineers can understand quickly
• Supported, secure runtime versions

Contact: contact@nexaarislabs.com

Nexaaris Labs Ltd is a private limited company registered in England and Wales, company number 16746745. Registered office: 2 Shepton Road, Broughton, Milton Keynes, Buckinghamshire, MK10 7AH, United Kingdom.