Yggdrasil

The world tree, whose branches and roots bind all nine realms together.

Image credit: @norsemythologyclips — go follow them.

Connective tissue for the Norse Architecture — Norse.Hosting: the web, worker, and migration service chassis and the deployables built on it. Yggdrasil hosts the runtime endpoints that Bifröst composes but never provides itself — every service, component, and contract it serves is declared in some other realm and lands here by reference. In the dependency chain it rides on Midgard and everything below; nothing rides on Yggdrasil, because a proving ground is the top of the tree.

The dependency graph

Arrows point at the thing depended on. Every edge is a declared reference in the owning .csproj; transitive dependencies are deliberately not redrawn (transitive-first is house law), with two recorded exceptions — Hosting.Web.Client's direct Infrastructure.Web.Grpc edge exists so the NORSE080 analyzer survives NuGet's transitive strip in package mode, and the Generator="true" marks on Infrastructure.Web.Server/.Web.Client attach Midgard's wiring generators to those compilations. Non-Norse packages (FluentUI, BlazingStory, protobuf-net, Scalar) are off the chart by convention.

flowchart BT
	subgraph Yggdrasil["Yggdrasil — Norse.Hosting"]
		WebServer["Hosting.Web.Server"]
		WebClient["Hosting.Web.Client"]
		WebComponents["Hosting.Web.Components"]
		Worker["Hosting.Worker"]
		MigrationsService["Hosting.Migrations.Service"]
		StoriesHost["Hosting.Stories"]
	end
	subgraph Asgard["Asgard — Norse.Abstractions"]
		AContracts["Abstractions.Contracts"]
		AWebServer["Abstractions.Web.Server"]
		AComponents["Abstractions.Components"]
	end
	subgraph Midgard["Midgard — Norse.Infrastructure"]
		MWebServer["Infrastructure.Web.Server"]
		MWebClient["Infrastructure.Web.Client"]
		MWebGrpc["Infrastructure.Web.Grpc"]
		Backend["Infrastructure.Backend"]
		PersistenceEF["Infrastructure.Persistence.EntityFramework"]
		Migrations["Infrastructure.Migrations"]
		ThemeFluentUI["Infrastructure.Components.Theme.FluentUI"]
		ServiceDefaults["Infrastructure.ServiceDefaults"]
		ServiceDefaultsAspNet["Infrastructure.ServiceDefaults.AspNet"]
	end
	subgraph Urdarbrunnr["Urðarbrunnr — Norse.Persistence"]
		UMigrations["Persistence.EntityFramework.Migrations"]
	end
	subgraph Himinbjorg["Himinbjörg — Norse.Identity"]
		IdentityWebServer["Identity.Web.Server"]
		IdentityMigrationsPg["Identity.Migrations.PostgreSQL"]
	end
	subgraph Heimdall["Heimdall — Norse.AuthN"]
		AuthNFluentUI["AuthN.Components.FluentUI"]
		AuthNServices["AuthN.Services"]
	end
	subgraph Mimisbrunnr["Mímisbrunnr — Norse.Reference.Data"]
		RefDataEF["Reference.Data.EntityFramework"]
		RefDataEFMigPg["Reference.Data.EntityFramework.Migrations.PostgreSQL"]
	end
	subgraph Mimir["Mímir — Norse.Reference"]
		RefContracts["Reference.Contracts"]
		RefComponentsFluentUI["Reference.Components.FluentUI"]
		RefWebServer["Reference.Web.Server"]
	end
	subgraph Bragi["Bragi — Norse.DesignSystem"]
		Stories["DesignSystem.Stories"]
	end
	subgraph Naglfar["Naglfar — Norse.DesignSystem"]
		Tokens["DesignSystem.Tokens"]
	end
	WebServer --> AContracts
	WebServer --> AWebServer
	WebServer --> AuthNFluentUI
	WebServer --> IdentityWebServer
	WebServer --> Backend
	WebServer --> ThemeFluentUI
	WebServer --> PersistenceEF
	WebServer --> ServiceDefaultsAspNet
	WebServer --> MWebServer
	WebServer --> RefDataEF
	WebServer --> RefWebServer
	WebServer --> WebClient
	WebClient --> AContracts
	WebClient --> AuthNFluentUI
	WebClient --> ThemeFluentUI
	WebClient --> MWebClient
	WebClient --> MWebGrpc
	WebClient --> RefContracts
	WebClient --> Tokens
	WebClient --> WebComponents
	WebComponents --> AComponents
	WebComponents --> RefComponentsFluentUI
	Worker --> ServiceDefaults
	MigrationsService --> IdentityMigrationsPg
	MigrationsService --> Backend
	MigrationsService --> Migrations
	MigrationsService --> ServiceDefaults
	MigrationsService --> UMigrations
	MigrationsService --> RefDataEFMigPg
	StoriesHost --> AuthNServices
	StoriesHost --> Stories
	StoriesHost --> ThemeFluentUI
	StoriesHost --> ServiceDefaultsAspNet

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What's hosted here

• Hosting.Web.Server — the platform's composition root: Blazor (server + WASM render modes), the hand-rolled mediator pipeline (AddNorsePipeline()), the code-first gRPC transport with its three-interceptor stack, Himinbjörg's identity persistence and its OpenIddict 8 server (authorization code + PKCE, rotating refresh tokens, revocation, and the bearer source behind Midgard's user and machine lanes), Heimdall's authn surface, Mímir's reference service and its REST facade, and the content-negotiated trilingual wire — one contract answering protobuf on the gRPC routes and JSON/XML through MVC's formatters, described by one OpenAPI document with Scalar as its dev-time face. Negotiation is honest: JSON is the default channel, XML is opt-in by Accept header, and anything else is a 406, never a silent fallback. Every policy is closed to the cookie's identity lane unless its declaration names another lane, so a bearer token reaches only the operations that admit it.
• Hosting.Web.Client — the browser: a cookie-credentialed gRPC-Web channel to the generated client proxies (AddNorseGrpcClients()), OutcomeClientInterceptor decoding wire failures back into Outcome<T>, and FluentUI theming seeded from Naglfar's token package.
• Hosting.Web.Components — the shared page shell (layout, nav, template pages, circuit safety net). Realm components arrive by the drop-in law: referencing the assembly is the registration — Mímir's CountryLookup page routed and served with no host edit beyond its nav entry.
• Hosting.Migrations.Service — the permanent three-line migrations deployable: AddNorseMigrations() discovers every contributor at compile time, runs them against Postgres, and exits clean. New bounded contexts join by reference, never by edit.
• Hosting.Stories — the BlazingStory catalog host for Bragi's DesignSystem.Stories, now Blazor Interactive Server (not WASM) and also exposing an MCP endpoint (AddBlazingStoryMcpServer()/MapBlazingStoryMcp()), published to ghcr.io/norsearchitecture/hosting/stories.
• Hosting.Worker — the one genuine stub left, waiting on the hosting abstractions from Asgard and Midgard.

Status

The tri-format wire is live end to end: the same country document answers over gRPC (the verbless /grpc.reference.v1.ReferenceService/GetCountry route) and over REST as content-negotiated JSON or XML (GET /api/reference/countries/US, served to a machine client's bearer token; ReferencePolicies.Public is the one policy that names the machine lane beside the cookie's, an exception for reference reads, while the gRPC lane never admits a machine token, and a bearer of the wrong kind for its lane gets a bare 401 challenge), the OpenAPI document declares exactly what the REST leg serves (with the standard idiomatic response codes stamped onto every operation; the gRPC leg's discovery surface is the reflection service, dev-only), and both discovery surfaces integrate with Postman/Bruno — Vafthrudnir's collections interrogate them, and the browser's CountryLookup proves the round trip by re-deriving the wire's v5 identifier from the client-baked dataset. Every deployable here follows the spec-first discipline: brainstorm → spec → plan in Glitnir's docs/Yggdrasil/, greenlit by the human, then code.

The cosmos

Yggdrasil is one realm of the Norse Architecture. The whole platform composes at Bifröst — clone once, cross the bridge, and every session starts there so decisions get brainstormed across the entire landscape, not in isolation. Every design is tried in Glitnir, the design court, before code is forged here.

Soundtrack: Yggdrasil