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Cratis

Cratis Arc.Core host selection

Cratis Arc’s Cratis.Arc.Core package lets a worker or console application run commands and queries without an ASP.NET Core dependency. Its optional HttpListener host exposes those operations over HTTP and can serve public static assets. Choose Cratis.Arc instead when you need ASP.NET Core hosting and middleware. Neither package requires event sourcing.

What Core provides

Section titled “What Core provides”

Core supplies the command and query pipelines, including model binding, validation, authorization, and result handling. Convention-based discovery and dependency injection connect your application types to those pipelines. Correlation IDs let you follow an operation, while identity and tenant context make the caller and tenant available to application code. Configure authorization and tenant membership for your application’s access rules.

The HTTP host adds manual endpoints, static files and single-page application fallback, and basic OpenAPI route metadata. A fallback serves the frontend’s entry file when an unmatched browser URL needs to reach its client-side router.

Your application
Cratis.Arc.Core
Command and query pipelines
Optional lightweight HTTP host
Cratis.Arc ASP.NET integration
Optional MongoDB or EF Core integration
Optional Chronicle event sourcing

You can add persistence without adding Chronicle. Check each integration’s dependencies when assembling your application; the absence of ASP.NET Core in the Core package does not apply automatically to every package you combine with it.

Comparison with ASP.NET Core

Section titled “Comparison with ASP.NET Core”
Capability Arc.Core lightweight host Arc with ASP.NET Core
Package Cratis.Arc.Core Cratis.Arc
HTTP server HttpListener ASP.NET hosting, commonly Kestrel
Request handling Arc’s simplified route/static/fallback handling ASP.NET middleware ecosystem
Manual routing Literal-path GET/POST helpers ASP.NET routing APIs
Static files Built-in support and SPA fallback ASP.NET static-file middleware
MVC/Razor Not included Available through ASP.NET
OpenAPI Basic route metadata in Core Optional Cratis.Arc.OpenApi or Cratis.Arc.Swagger
Pipelines, validation, identity, tenant context Available Available

The Core host checks registered routes, then static files, then the fallback. Changing the order of those configuration calls does not create an ASP.NET-style middleware pipeline. Named endpoint groups are not supported because this host cannot restrict a route to a particular local port.

Here, lightweight describes the hosting dependency boundary. It does not guarantee native AOT compatibility or a particular startup time, memory use, deployment size, or throughput. Check your publish configuration and measure the workload with the discovery, serialization, and integrations you use.

When to choose each host

Section titled “When to choose each host”

Choose Core when you want to expose a small service or give a worker management endpoints without taking on ASP.NET Core. It also lets you learn the command and query pipelines in a console project.

Choose the ASP.NET Core integration when your application needs controllers, Razor, advanced routing, standard authentication middleware, or other ASP.NET libraries. Core does not supply a gRPC server or other protocol hosts.

Architecture

Section titled “Architecture”

The builder registers services. UseCratisArc() maps Arc endpoints and schedules the HTTP listener to start when the application starts. This bootstrap fragment belongs in a console project’s Program.cs with using Cratis.Arc;:

var builder = ArcApplication.CreateBuilder(args);
builder.AddCratisArc();
var app = builder.Build();
app.UseCratisArc();
await app.RunAsync();

The default listener binds http://+:5001/. Start with the getting-started checkpoint, which sets an explicit loopback URL and supplies a complete command and query. Review discovery access defaults before exposing the host.

Next steps

Section titled “Next steps”

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