A dotnet new template for a GraphQL API using Hot Chocolate in .NET 10, built with a streamlined Clean Architecture. All the layers you need, none of the ceremony you don't.

It's one of five Lean Mean Clean Apps templates. They share the same Application and Infrastructure layers and differ only in how they face the world. Same genes, different haircuts.

The guides, the reference and the reasoning behind every opinion live at leanmeancleanapps.github.io/graphql. This is the version for people who skim. We see you.

Get started

You need the .NET 10 SDK. Docker is optional, but it's the quickest way to see it running.

# Install the template
dotnet new install CleanGraphQLApi.Template

# Create a solution
dotnet new cleangraphqlapi --name Acme.Reviews --authorName "Your Name"
cd Acme.Reviews

Option	What it does
--name	Names the solution and its root namespace
--authorName	Puts your name on the assembly instead of ours
--authority	Your OAuth authorization server. Leave it out and the API runs without authentication
--audience	The audience tokens must be issued for, usually the API's own URL

That's three layers, four test projects, a Dockerfile and a CI pipeline. Go and tell your team you've been working on it all week.

Run it

# Build the image and start it with sample data, plus Seq for the logs
docker compose up -d --build

# Ask it for a page of movies
curl http://localhost:8080/graphql \
  -H 'Content-Type: application/json' \
  -d '{ "query": "{ movies(query: \"global\", first: 2) { totalCount nodes { title reviewCount averageStars } } }" }'

{
  "data": {
    "movies": {
      "totalCount": 2,
      "nodes": [
        {
          "title": "Assimilated global infrastructure",
          "reviewCount": 1,
          "averageStars": 1
        },
        {
          "title": "Automated global alliance",
          "reviewCount": 3,
          "averageStars": 3.3
        }
      ]
    }
  }
}

Yes, the sample movies are named by a corporate buzzword generator, and the critics are harsh.

Typing GraphQL into curl is a character-building exercise. Open Nitro, the GraphQL IDE, at http://localhost:8080/graphql instead, where the schema is documented from the same XML comments as the code.

The movies, authors and reviews queries use Relay-style cursor paging (first, after, pageInfo, totalCount). Movies and authors come with their review count and average stars, worked out by the database rather than in a loop somewhere. Ask for their reviews and a DataLoader fetches them for the whole page at once, so 50 movies take three queries, not 52. The logs land in Seq at http://localhost:5341.

No Docker? dotnet run --project src/Presentation works too. Every other way to run it, from plain docker run to stamping a version into the image, is in docs/RUN.md.

The API is open until you give it an authorization server. Pass --authority and --audience when you create the solution, or set Authentication:Authority later, and the movie, author and review queries and the review mutations start asking for a JWT bearer token. The version query, the schema and Nitro stay open. Securing the API has the details.

What's inside

Three layers, loosely based on Clean Architecture. Fewer layers than an onion, more than a sandwich.

• Presentation is the GraphQL schema, built by Hot Chocolate with source-generated types. Queries and mutations send each request through Mediator, and Application errors become GraphQL errors with codes in their extensions.
• Application owns the rules. Commands and queries are validated by FluentValidation and mapped by Mapperly.
• Infrastructure owns the data, with Entity Framework Core on SQLite. Everything in it is internal, so Presentation can wire it up but can't move in.

There's a little CQRS in how commands and queries are shaped, but reads and writes share one database underneath. CQRS-curious, not CQRS-committed.

And around the edges:

• Tests use xUnit, Shouldly and NSubstitute, with coverage from Coverlet. Each test gets its own throwaway in-memory database, so no test can spoil another one's data.
• Sample data comes from Bogus, and only when Database:SeedSampleData is on. A real deployment never starts with fake reviews.
• Logs go through Serilog, to the console and to Seq when you run it with Docker Compose. Health checks answer at /health/live and /health/ready.
• Build rules live in Directory.Build.props. Code style and the recommended analyzers run on every build, warnings fail it, and package versions sit in one place with Central Package Management.
• The container runs as a non-root user and has its own health check.
• The pipeline builds, checks formatting, tests with a 95% coverage bar, makes sure the packed template still works, runs CodeQL, reviews new dependencies and their licences, starts the image to check it actually answers, and scans the container and Dockerfile with Trivy. Then it sums the lot up in one comment on your pull request, so you know exactly who to blame. It needs no accounts, tokens or secrets, so your copy works the moment you push it. Trust is earned.
• Dependabot bundles the month's dependency updates into one pull request on the 15th.

The architecture page has the long version, with full credit to Jason Taylor's template and Uncle Bob for the ideas.

Releases

A new version lands on the 1st of each month, as long as something changed, with notes for every pull request in the GitHub release. No changes, no release. We're not here to pad the download stats. Each release also carries an SPDX bill of materials listing every package the API ships with, for anyone whose security team asks nicely (or not so nicely).

dotnet new update

The family

Template	Presentation
Clean Minimal API	ASP.NET Core Minimal APIs
Clean Model Context Protocol	Model Context Protocol server
Clean GraphQL API	GraphQL with Hot Chocolate, you are here
Clean Web API	ASP.NET Core controllers
Clean Lambda Function	AWS Lambda

Contributing

Bug reports, ideas and pull requests are all welcome, and typo fixes doubly so. Start with the contributing guide and the code of conduct. Security problems go through the security policy, not an issue.

Who built this

Built by Stephen Walsh in spare time, with strong coffee and a healthy disregard for pomp and ceremony. Say hello on GitHub, LinkedIn, Medium or at stphnwlsh.github.io.

If this template saves you some time, sponsoring the work keeps all five templates current and the coffee flowing, which is the real dependency here.

License

MIT. Take it, change it, ship it. Just don't blame us for your N+1 queries. We already fixed ours.