GraphZen

A code-first GraphQL framework for .NET.

GraphZen lets you define GraphQL schemas using plain C# classes and conventions, with full support for queries, mutations, subscriptions, and an integrated playground UI. It handles schema generation, query parsing, validation, and execution out of the box.

Project status: This project is being actively revived after a period of dormancy. Expect breaking changes as the codebase is modernized.

Quick Start

Prerequisites

• .NET 10.0 SDK or later

Installation

dotnet add package GraphZen.AspNetCore.Server

Define your schema

GraphZen discovers your schema from plain C# classes by convention. Define Query, Mutation, and model types as regular classes:

public class Post
{
    public int Id { get; set; }
    public string Title { get; set; }
    public string Author { get; set; }
    public string Content { get; set; }
}

public class Query
{
    [Description("Get the latest blog posts")]
    public List<Post> Posts(int? postId)
    {
        if (postId != null)
            return FakeBlogData.Posts.Where(_ => _.Id == postId.Value).ToList();

        return FakeBlogData.Posts;
    }
}

public class Mutation
{
    [Description("Add a new post")]
    public bool AddPost(string author, string title, string post)
    {
        FakeBlogData.Posts.Add(new Post
        {
            Id = FakeBlogData.Posts.Max(_ => _.Id) + 1,
            Author = author,
            Title = title,
            Content = post
        });
        return true;
    }
}

Wire it up in ASP.NET Core

public class Startup
{
    public void ConfigureServices(IServiceCollection services)
    {
        services.AddGraphQLContext();
    }

    public void Configure(IApplicationBuilder app, IWebHostEnvironment env)
    {
        app.UseRouting();
        app.UseEndpoints(endpoints =>
        {
            endpoints.MapGraphQL();
            endpoints.MapGraphQLPlayground();
        });
    }
}

That's it. Run the app and open the root URL to access the GraphQL Playground.

Schema builder API

For more control, you can define your schema explicitly using the GraphQLContext builder API:

public class BlogContext : GraphQLContext
{
    protected internal override void OnSchemaCreating(SchemaBuilder schema)
    {
        schema.Object("Post")
            .Field("id", "Int!")
            .Field("title", "String")
            .Field("author", "String")
            .Field("content", "String");

        schema.Object("Query")
            .Field("posts", "[Post]")
            .Field("post", "Post");
    }
}

Features

• Code-first schema definition -- define your GraphQL schema using C# classes with convention-based discovery, or use the explicit schema builder API
• Full type system -- objects, interfaces, unions, enums, input types, and custom scalars
• Query execution engine -- parsing, validation, and execution of GraphQL queries
• ASP.NET Core integration -- middleware, endpoint routing, and dependency injection
• Built-in GraphQL Playground -- interactive GraphQL IDE served directly from your app
• GraphQL client -- GraphQLClient for consuming GraphQL APIs over HTTP

Packages

Package	NuGet
Server
GraphZen.AspNetCore.Server
SDK
GraphZen.Abstractions
GraphZen.LanguageModel
GraphZen.TypeSystem
GraphZen.QueryEngine

Building from source

git clone https://github.com/GraphZen/graphzen-dotnet.git
cd graphzen-dotnet
dotnet build
dotnet test

License

GraphZen is licensed under the GraphZen Community License (AGPLv3 with Commons Clause). Commercial licenses are available at graphzen.com.

Copyright 2017-2026 GraphZen LLC. "GraphZen" is a registered trademark of GraphZen LLC.