.NET (C#) SDK Overview

The Invoke C# SDK (Invoke.SDK) provides everything you need to write serverless functions in C# targeting .NET 10 NativeAOT.

Setup

Add the following app.csproj to your function directory:

<Project Sdk="Microsoft.NET.Sdk">
  <PropertyGroup>
    <OutputType>Exe</OutputType>
    <TargetFramework>net10.0</TargetFramework>
    <Nullable>enable</Nullable>
    <ImplicitUsings>enable</ImplicitUsings>
    <AllowUnsafeBlocks>true</AllowUnsafeBlocks>
    <PublishAot>true</PublishAot>
    <InvariantGlobalization>true</InvariantGlobalization>
  </PropertyGroup>
  <ItemGroup>
    <PackageReference Include="Invoke.SDK" Version="1.*" />
  </ItemGroup>
</Project>

The [EntryPoint] Attribute

Every C# function must mark its entry point with [EntryPoint]. The SDK's source generator reads this attribute and generates Program.Main automatically.

Three patterns are supported:

Simple Function — static method

using Invoke;
using System.Text.Json.Nodes;

public static class Function
{
    [EntryPoint]
    public static Task EntryPoint(InvokeRequest req, InvokeResponse res)
    {
        res.Status(200).Json(new JsonObject { ["message"] = "Hello, World!" });
        return Task.CompletedTask;
    }
}

Multi-Route App — Router subclass

using Invoke;
using System.Text.Json.Nodes;

[EntryPoint]
public partial class App : Router
{
    [HttpGet("/")]
    public Task Index(InvokeRequest req, InvokeResponse res)
    {
        res.Status(200).Json(new JsonObject { ["message"] = "Hello" });
        return Task.CompletedTask;
    }

    [HttpPost("/echo")]
    public Task Echo(InvokeRequest req, InvokeResponse res)
    {
        res.Status(200).Json(req.Body);
        return Task.CompletedTask;
    }
}

Realtime Handler — RealtimeNamespace subclass

using Invoke;
using System.Text.Json.Nodes;

[EntryPoint]
public partial class App : RealtimeNamespace
{
    public App()
    {
        Namespace = "/chat";
    }

    [RealtimeEvent("message")]
    public async Task OnMessage(JsonNode arg)
    {
        await To("room").Emit("message", arg);
    }
}

Namespaces

Namespace	Content
Invoke	InvokeRequest, InvokeResponse, Router, RealtimeNamespace, KeyValueStore, Logger, ChildLogger, and all attributes

All types are available via using Invoke;. No additional namespaces are required for core functionality.

Available APIs

API	Type	Description
InvokeRequest	Class	Incoming HTTP request data
InvokeResponse	Class	Fluent response builder
Router	Abstract class	Attribute-based HTTP routing
KeyValueStore	Class	Persistent distributed KV storage
RealtimeNamespace	Abstract class	Socket.IO event-driven handlers
Logger	Static class	Structured logging with levels and child loggers