Publishing to NuGet | Fern Documentation

Publish your public-facing Fern C#/.NET SDK to the NuGet registry. After following the steps on this page, you’ll have a versioned package published on NuGet.

This page assumes that you have:

An initialized fern folder. See Set up the fern folder.
A GitHub repository for your C#/.NET SDK. See Project structure.
A C#/.NET generator group in generators.yml. See C#/.NET Quickstart.

Configure SDK package settings

You’ll need to update your generators.yml file to configure the package name, output location, and client name for NuGet publishing. Your generators.yml should live in your source repository (or on your local machine), not the repository that contains your C#/.NET SDK code.

Configure `output` location

In the group for your C#/.NET SDK, change the output location from local-file-system (the default) to nuget to indicate that Fern should publish your package directly to the npm registry:

generators.yml

1 groups: 
2   csharp-sdk:
3 	generators:
4 	  - name: fernapi/fern-csharp-sdk
5 	    version: 2.1.16-rc0
6 		output:
7 		  location: nuget

Add a unique package name

Your package name must be unique in the NuGet repository, otherwise publishing your SDK to NuGet will fail.

generators.yml

1 groups: 
2   csharp-sdk:
3 	generators:
4 	  - name: fernapi/fern-csharp-sdk
5 		version: 2.1.16-rc0
6 		output:
7 		  location: nuget
8 		  package-name: your-package-name

Configure `client-class-name`

The client-class-name option controls the name of the generated client. This is the name customers use to import your SDK (import { your-client-name } from 'your-package-name';).

generators.yml

1 groups: 
2   csharp-sdk:
3     generators:
4       - name: fernapi/fern-csharp-sdk
5         version: 2.1.16-rc0
6         output:
7           location: nuget
8           package-name: your-package-name
9         config:
10           client_class_name: YourClientName # must be PascalCase

Generate a NuGet API key

Log into NuGet

Log into NuGet or create a new account.

Add New Key

Click on your profile picture.
Select API Keys, then Create.
Name your key.
Select Push > Push new packages and package versions as the Select Scopes type.
Enter * under Select Packages > Glob Patten.

Replacing an existing NuGet package
If you are overriding an existing package, you can select the relevant package instead of entering *.
Click Create.

Save your new key – it won’t be displayed after you leave the page.

Configure NuGet publication

Add repository location

Add the path to the GitHub repository containing your C#/.NET SDK:

generators.yml

1 groups: 
2   csharp-sdk:
3     generators:
4       - name: fernapi/fern-csharp-sdk
5         version: 2.1.16-rc0
6         output:
7           location: nuget
8           package-name: your-package-name
9         config:
10           client_class_name: YourClientName
11         github: 
12           repository: your-org/company-csharp

Configure NuGet authentication key

Add api-key: ${NUGET_API_KEY} to generators.yml to tell Fern to use the NUGET_API_KEY environment variable for authentication when publishing to the NuGet registry.

generators.yml

1 groups: 
2   csharp-sdk:
3     generators:
4       - name: fernapi/fern-csharp-sdk
5         version: 2.1.16-rc0
6         output:
7           location: nuget
8           package-name: your-package-name
9           api-key: ${NUGET_API_KEY}
10         config:
11           client_class_name: YourClientName
12         github: 
13           repository: your-org/company-csharp

Choose your publishing mode

Optionally set the mode to control how Fern handles SDK publishing:

mode: release (default): Fern generates code, commits to main, and tags a release automatically
mode: pull-request: Fern generates code and creates a PR for you to review before release
mode: push: Fern generates code and pushes to a branch you specify for you to review before release

You can also configure other settings, like the reviewers or license. Refer to the full github (generators.yml) reference for more information.

generators.yml

1 groups: 
2   csharp-sdk:
3     generators:
4       - name: fernapi/fern-csharp-sdk
5         version: 2.1.16-rc0
6         output:
7           location: nuget
8           package-name: your-package-name
9           api-key: ${NUGET_API_KEY}
10         config:
11           client_class_name: YourClientName
12         github: 
13           repository: your-org/company-csharp
14 		  mode: push
15 		  branch: your-branch-name # Required for mode: push

Publish your SDK

Decide how you want to publish your SDK to NuGet. You can use GitHub workflows for automated releases or publish directly via the CLI.

Release via a GitHub workflow

Set up a release workflow via GitHub Actions so you can trigger new SDK releases directly from your source repository.

Set up authentication

Open your source repository in GitHub. Click on the Settings tab. Then, under the Security section, open Secrets and variables > Actions.

You can also use the url https://github.com/<your-repo>/settings/secrets/actions.

Add secret for your NuGet API key

Select New repository secret.
Name your secret NUGET_API_KEY.
Add the corresponding API key you generated above.
Click Add secret.

Add secret for your Fern Token

Select New repository secret.
Name your secret FERN_TOKEN.
Add your Fern token. If you don’t already have one, generate one by running fern token. By default, the fern_token is generated for the organization listed in fern.config.json.
Click Add secret.

Set up a new workflow

Set up a CI workflow that you can manually trigger from the GitHub UI. In your repository, navigate to Actions. Select New workflow, then Set up workflow yourself. Add a workflow that’s similar to this:

.github/workflows/publish.yml

1 name: Publish C#/.NET SDK
2 
3 on:
4   workflow_dispatch:
5     inputs:
6       version:
7         description: "The version of the C#/.NET SDK that you would like to release"
8         required: true
9         type: string
10 
11 jobs:
12   release:
13     runs-on: ubuntu-latest
14     steps:
15       - name: Checkout repo
16         uses: actions/checkout@v4
17 
18       - name: Install Fern CLI
19         run: npm install -g fern-api
20 
21       - name: Release C#/.NET SDK
22         env:
23           FERN_TOKEN: ${{ secrets.FERN_TOKEN }}
24           NUGET_API_KEY: ${{ secrets.NUGET_API_KEY }}
25         run: |
26           fern generate --group csharp-sdk --version ${{ inputs.version }} --log-level debug

You can alternatively configure your workflow to execute on: [push]. See Vapi’s npm publishing GitHub Action for an example.

Regenerate and release your SDK

Navigate to the Actions tab, select the workflow you just created, specify a version number, and click Run workflow. This regenerates your SDK.

The rest of the release process depends on your chosen mode:

Release mode (default): If you didn’t specify a mode or set mode: release, no further action is required. Fern automatically tags the new release with your specified version number and initiates the publishing workflow in your SDK repository.
Pull request or push mode: If you set mode: pull-request or mode: push, Fern creates a pull request or pushes to a branch respectively. Review and merge the PR (pull-request) or branch (push), then tag a new release to initiate the publishing workflow in your SDK repository.

Once the workflow completes, you can view your new release by logging into NuGet and navigating to Manage Packages.

Release via CLI and environment variables

Set npm environment variable

Set the NUGET_API_KEY environment variable on your local machine:

$ export NUGET_API_KEY=your-actual-nuget-api-key

Regenerate and release your SDK

Regenerate your SDK, specifying the version:

$ fern generate --group csharp-sdk --version <version>

The rest of the release process depends on your chosen mode:

Release mode (default): If you didn’t specify a mode or set mode: release, no further action is required. Fern automatically tags the new release with your specified version number and initiates the publishing workflow in your SDK repository.
Pull request or push mode: If you set mode: pull-request or mode: push, Fern creates a pull request or pushes to a branch respectively. Review and merge the PR (pull-request) or branch (push), then tag a new release to initiate the publishing workflow in your SDK repository.

Once the workflow completes, you can view your new release by logging into NuGet and navigating to Manage Packages.

Configure SDK package settings

Configure output location

Add a unique package name

Configure client-class-name

Generate a NuGet API key

Log into NuGet

Add New Key

Replacing an existing NuGet package

Configure NuGet publication

Add repository location

Configure NuGet authentication key

Choose your publishing mode

Publish your SDK

Release via a GitHub workflow

Set up authentication

Add secret for your NuGet API key

Add secret for your Fern Token

Set up a new workflow

Regenerate and release your SDK

Release via CLI and environment variables

Set npm environment variable

Regenerate and release your SDK

Configure `output` location

Configure `client-class-name`