SvelteNet

Svelte 5 islands for ASP.NET Razor Pages and MVC — SvelteKit-style typed data props, forms, and remote functions, powered by your C# models.

• Svelte 5 / runes — components receive props via $props(), mounted with mount/hydrate; experimental await expressions supported (sveltenet({ experimentalAsync: true })).
• SSR is opt-in and interchangeable — stay client-only, run in-process with Jint, use an installed Node.js/Bun CLI, or plug in your own ISvelteSsrEngine.
• Typed everything, generated for you — [SvelteProp] page models, [SvelteComponent] MVC view models, and [SvelteRemote] services all emit TypeScript; remote dispatch is compiled by a Roslyn source generator.
• SvelteKit-style remote functions — [Query]/[Command]/[Form] methods become query/command/form clients with caching, refresh(), .updates(), fields/issues state, and no-JS fallbacks.
• One-plugin Vite setup — plugins: [sveltenet()] builds client + SSR bundles in a single vite build; full HMR in development.

Quickstart

// Program.cs
using SvelteNet.AspNetCore;
builder.Services.AddRazorPages();
builder.Services.AddSvelteNet(); // client-only
// Or: builder.Services.AddSvelteNet().AddJintSSR();
var app = builder.Build();
app.UseStaticFiles();
app.UseSvelteNet();          // maps /_sveltenet/remote
app.MapRazorPages();

public class IndexModel : SveltePage
{
    [SvelteProp] public List<Todo> Todos { get; set; } = [];
}

@model IndexModel
@section Head { @Model.SvelteHead() }
@Model.Svelte()

Run dotnet build once. The bundled analyzer and build target generate ambient declarations under .svelte-net/types and scaffold missing user-owned .svelte/Vite files. Then run npm install + npm run dev alongside dotnet watch run.

Documentation

• Getting started — setup, scaffolding, project layout
• Dev mode & hot reload — the two-terminal workflow, HMR, caveats
• Forms & enhance — page forms, data.problem, antiforgery, progressive enhancement
• MVC views — [SvelteComponent] typed rendering, @Html.Svelte
• Remote functions — [Query]/[Command]/[Form], the typed client, source-generated dispatch
• SSR renderers — opt-in Jint, Node.js, Bun, and custom renderers
• Security — authorization, CSRF, and what the SSR bridge enforces
• Options — shared and renderer-specific configuration

Repository layout

src/       SvelteNet.Core          — renderer, serialization contract, TypeScript generation (NuGet)
           SvelteNet.AspNetCore    — ASP.NET integration, Node/Bun SSR, remote endpoints (NuGet)
           SvelteNet.Jint          — in-process Jint server rendering (NuGet, optional)
           SvelteNet.Generators    — Roslyn source generator for remote dispatch
           SvelteNet.Build         — MSBuild target: dotnet build generates the TS types
           SvelteNet.FluentValidation — FluentValidation adapter for the validation pipeline
packages/  sveltenet               — Vite plugin + client/remote runtimes (npm)
samples/   TodoApp                 — Razor Pages: typed props, forms, enhance()
           RemoteFunctions         — vertical-slice query/command/form functions and async SSR
           MvcHello                — MVC controllers with [SvelteComponent]
tests/     SvelteNet.Core.Tests, SvelteNet.AspNetCore.Tests
docs/      the documentation above (also a VitePress site: bun run docs:dev)

Development

The repo uses bun (bun.lock is committed), but every script calls tools directly, so npm/pnpm work too.

dotnet test SvelteNet.slnx              # .NET unit + integration tests
bun install                             # workspace install (packages/ + samples/ + docs/)
cd packages/sveltenet && bun run test   # JS tests
cd samples/TodoApp && dotnet run        # any sample: see samples/README.md
bun run docs:dev                        # documentation site

Status

Prototype — not yet published to NuGet or npm. See ROADMAP.md for what's next (publishing and Blazor/Blazor-SSR hosting) and what has shipped.