.NET and C#

.NET development for services that must work every day

A good backend is noticed most when it goes unnoticed. Users should be able to sign in, add items to the cart, pick a delivery slot, and use their coupons without thinking about which services talk to each other behind the scenes. We have worked in a large C# and .NET microservice platform with hundreds of projects behind a national loyalty and online grocery service — members, cart, orders, delivery slots, coupons, and search.

We have also built smaller, focused tools. One example is a .NET 10 service that syncs store opening hours to Google Business Profile and Apple Maps, so customers see the right hours where they actually look.

Architecture choices in C# and ASP.NET Core projects

Some decisions we make early, because they are expensive to change later:

• Isolated worker for Azure Functions. It is the model Microsoft recommends for new functions, and it gives the same .NET version, middleware, and dependency injection as the rest of the codebase.
• Generated clients from OpenAPI. Kiota or NSwag produce typed clients, so a broken contract is caught at build time rather than in production.
• Resilience at the boundaries. Polly policies and caching wrap calls to other systems instead of being scattered through the domain logic.
• Real databases in tests. Testcontainers rather than in-memory databases, because SQL, transactions, and migrations should be tested the way they actually run.
• Explicit migrations. DbUp when the team wants to own the SQL, Entity Framework Core migrations when the model is driven from code.

We are also wary of layers that do not pay for themselves. MediatR and custom abstractions can bring order to large codebases, but in a small service a straightforward ASP.NET Core endpoint is often easier to read and debug.

ASP.NET Core, Azure Functions, and .NET Aspire

Many .NET solutions combine APIs, background jobs, and event flows. We use ASP.NET Core and YARP for APIs and gateways, Azure Functions and Durable Functions for event-driven processes and long-running workflows, and .NET Aspire to make local development with several services simpler. Data lives in Azure SQL, Cosmos DB, or Elasticsearch depending on how it is used, and messages flow through Kafka where systems need to stay loosely coupled.

We also contribute to open source in C#, including a BTCPay Server plugin that lets merchants receive Lightning payments directly to a Bare Bitcoin account.