.NET Development Services for US & EU Enterprises and Regulated SaaS

.NET wins when your customers live in Azure or run on-prem Windows, when your domain is rich and benefits from C# records, pattern matching and source generators, and when you want first-class native AOT, async/await and ValueTask without the runtime tax of the JVM. Pick Java when your operations team is already on JVM observability and the talent pool locally favours it. Pick Node.js for I/O-heavy web BFFs. Pick Go for static binaries you ship to edge or CLI. We run polyglot teams and recommend .NET only when it earns the slot.

.NET 9 (STS, supported through May 2026) is current default. .NET 10 LTS lands November 2025 and becomes our new-build default by December 2025, supported through November 2028. C# 13 with collection expressions and primary constructors. We migrate STS-pinned codebases to the next LTS before STS support expires — never let an unsupported runtime sit in production. EF Core 9 default, EF Core 10 once the .NET 10 ecosystem catches up Q1 2026.

Yes. Default deployment is Azure West Europe, North Europe, Germany West Central or France Central; AWS eu-central-1 / eu-west-1 for cross-cloud; on-prem Windows Server / RHEL where the regulator requires it. PII encrypted with Azure Key Vault or AWS KMS keys held in customer tenant. We ship GDPR Article 28 DPAs, DPIAs for high-risk, Article 30 records. For DORA (EU financial services, Jan 2025) we provide ICT third-party register documentation, incident classification, and resilience testing artefacts. HIPAA-capable for US healthtech with BAAs in place via Azure HIPAA-eligible services.

Incremental, never big-bang. Step 1: .NET Upgrade Assistant for low-risk projects (class libraries, console apps). Step 2: side-by-side host — new ASP.NET Core endpoints behind YARP reverse proxy in front of the legacy IIS app, route by URL. Step 3: replace WCF with gRPC or REST + MediatR contracts. Step 4: replace WebForms screens one bounded context at a time with Blazor or React. Typical 500k-LOC enterprise monolith takes 9 to 14 months with no customer-visible downtime and no feature freeze.

Yes. Blazor United from .NET 8 (and refined in .NET 9/10) is now the default for new internal-tools and B2B SaaS UIs — one component model, render-mode chosen per route (Server, WASM, SSR, or auto). Blazor Server still wins for low-latency LAN apps with rich state. Blazor WebAssembly with AOT for offline-capable B2C. We have shipped a 240-screen Blazor United B2B SaaS with sub-100 ms TTI on cached routes and full keyboard-driven UX for power users.

.NET builds are fixed-scope and all-in, quoted in USD, tiered by what you are building. A web app MVP or internal client dashboard runs from $4,100 (4–8 weeks); a CRM or B2B portal with roles, admin and integrations from $8,100 (8–12 weeks); a multi-tenant SaaS platform from $13,800 (12+ weeks); a marketplace or highload system from $28,700. The exact number depends on how much legacy you carry, how many client surfaces you need, your data and messaging complexity, and domain compliance depth (PCI DSS, HIPAA, EU DORA). You see the line-item budget at the end of discovery and sign off before any code is written. No recruitment markup, no tool surcharges and no hidden fees. Cloud fees run on your own Azure or AWS accounts, so you keep the cost lever.

We pick the isolation model to fit your compliance and cost envelope: shared database with a tenant discriminator and EF Core global query filters for the many-small-tenants case; schema-per-tenant when a regulator wants logical separation; database-per-tenant for enterprise customers who demand their own encryption keys and backup cadence. Tenant resolution runs in ASP.NET Core middleware (host, path or JWT claim), with per-tenant configuration, feature flags and rate limits. Background work is tenant-aware on MassTransit so one noisy tenant never starves the rest. We ship the onboarding, billing-hook and per-tenant observability from day one, not as a retrofit.

Yes, integration is usually the hard 40% of an enterprise build and we scope it explicitly. We run bidirectional 1C sync in production (a live auto-parts catalog where prices shift hourly), talk to SAP over OData or BAPI/IDoc, drive Salesforce and Dynamics through their REST APIs, and wrap legacy SOAP/WCF endpoints behind clean REST or gRPC contracts so the rest of your estate never sees the SOAP. Messaging goes through MassTransit on RabbitMQ or Azure Service Bus with the outbox pattern for exactly-once semantics, and every external call is wrapped in Polly retries, circuit breakers and timeouts so a flaky third party cannot take your system down.

Every service ships with OpenTelemetry traces, metrics and structured logs into Azure Monitor / Application Insights, Grafana + Prometheus or Datadog — your stack, not ours. Health checks feed Kubernetes or App Service probes; alerts route to your on-call. We agree SLAs up front (typical target 99.9% for business apps, 99.95%+ for revenue-critical systems) and back them with load-tested capacity headroom measured on NBomber. Post-launch we offer tiered support — from business-hours maintenance to 24/7 on-call with a named engineer — and a warranty window on defects introduced by us.

Yes. We use the Microsoft.Extensions.AI abstractions and Semantic Kernel to add retrieval-augmented generation, structured extraction and agent workflows to existing .NET systems without bolting on a separate Python service. Vector search runs on Azure AI Search, pgvector on PostgreSQL or Qdrant; models can be OpenAI, Azure OpenAI, Anthropic Claude or a self-hosted open model where data residency or cost demands it. We keep the AI layer behind an interface so you can swap providers, and we ship guardrails — input validation, output grounding against your own data, and cost/latency budgets — so an LLM feature is production-safe, not a demo.