Expose Backend

Your stack:

Goal

Turn a .NET class into a remotely callable backend service using Graftcode Gateway - no controllers, no REST routes, no OpenAPI specs needed.

What You'll See

Create a small .NET class library with public methods.
Host it through Graftcode Gateway using Docker.
Explore the exposed methods in Graftcode Vision - your service is now accessible from any app as a strongly-typed client.

Prerequisites

Docker installed and running
.NET SDK installed locally

Step 1. Create a project folder

Create a new .NET class library project:

dotnet new classlib -n EnergyService
cd EnergyService

Step 2. Write a .NET class with public methods

Delete the auto-generated Class1.cs and create a file EnergyPriceCalculator.cs:

namespace EnergyService;

public class EnergyPriceCalculator
{
    public static int GetPrice()
    {
        return new Random().Next(100, 105);
    }
}

This is a plain C# class - no attributes, no frameworks, no special annotations. Any public method you write here will automatically become available for remote consumption once hosted through Graftcode Gateway.

Step 3. Host it with Graftcode Gateway

Create a Dockerfile in the project root:

FROM mcr.microsoft.com/dotnet/sdk:9.0

WORKDIR /usr/app

COPY . /usr/app/

RUN dotnet build
RUN dotnet publish -c Release -o /usr/app/

RUN apt-get update \
&& apt-get install -y wget \
&& wget -O /usr/app/gg.deb https://github.com/grft-dev/graftcode-gateway/releases/latest/download/gg_linux_amd64.deb \
&& dpkg -i /usr/app/gg.deb \
&& rm /usr/app/gg.deb \
&& apt-get clean \
&& rm -rf /var/lib/apt/lists/*

EXPOSE 80
EXPOSE 81

CMD ["gg", "--modules", "EnergyService.dll"]

The key line is the last one - gg (Graftcode Gateway) analyzes your EnergyService.dll, discovers all public methods in your assembly, and exposes them automatically. Port 80 handles service calls, port 81 serves Graftcode Vision.

Build and run the container:

docker build --no-cache --pull -t myenergyservice-dotnet:test .
docker run -d -p 80:80 -p 81:81 --name graftcode_demo_dotnet myenergyservice-dotnet:test

Your .NET service is now running and exposed through Graftcode Gateway.

Step 4. Explore the service in Graftcode Vision

Open http://localhost:81/GV in your browser.

You will see all public methods from your .NET class - their names, parameter types, and return types. Graftcode Vision also provides:

A "Try it out" button to call methods live, directly from the browser.
A package manager command (npm, NuGet, PyPI, etc.) to install this service as a strongly-typed client in any other application.

Step 5. Run with a Project Key (recommended for real-world usage)

Everything above works without any account - perfect for learning and local development. When you're ready for real-world usage, create a free account at portal.graftcode.com, set up a project, and copy its Project Key.

Then pass the key when starting your gateway:

CMD ["gg", "--modules", "EnergyService.dll", "--projectKey", "YOUR_PROJECT_KEY"]

A Project Key gives you:

Stable registry URL - consumers always find and update your Graft through a permanent address, so install commands don't change when you redeploy.
Portal visibility - see all your gateways and exposed services in one place at gateways.graftcode.com.
Access control - decide who can download your Grafts using package manager authentication and permissions.
MCP endpoint - Graftcode Gateway automatically exposes an MCP (Model Context Protocol) endpoint alongside your service, making your methods callable by AI agents and LLM-based tools out of the box.

Step 6. Call it from another app

Your service is now accessible from any application. From Graftcode Vision, select your target package type - for example NuGet - and copy the generated install command. That installs a Graft: a strongly-typed client that lets any app call your service methods directly.

using graft.nuget.energypricecalculator;

var price = await EnergyPriceCalculator.GetPrice();
Console.WriteLine(price);

No REST clients, no request/response models, no endpoint URLs in your code. When you add or update a public method, consumers update their Graft with a single package manager command.