Clerk SDK for .NET

Looking for ASP.NET Core w/ Clerk JWTs? See below.

Packages

Clerk.Net: Provides the standalone API Client as a Kiota-generated wrapper over Clerk's OpenAPI spec. Compatible with .NET 6+ and .NET Framework 4.7.2+.

Clerk.Net.DependencyInjection: Extensions to register the ClerkApiClient into your DI container. Compatible with .NET 6+.

These libraries are configured as native AoT compatible for .NET 8+ consumers.

Getting Started

Make sure to add your SecretKey to your application configuration, ideally via the dotnet secrets manager.

DI Container Configuration (ASP.NET Core & Worker Services)

1. Install Clerk.Net.DependencyInjection from Nuget.
2. Add the following code to your service configuration:

builder.Services.AddClerkApiClient(config =>
{
    config.SecretKey = builder.Configuration["Clerk:SecretKey"]!;
});

3. Request the ClerkApiClient in your services

public class MyBackgroundWorker : BackgroundService
{
    private readonly ClerkApiClient _clerkApiClient;

    public MyBackgroundWorker(ClerkApiClient clerkApiClient)
    {
        _clerkApiClient = clerkApiClient;
    }

    protected override async Task ExecuteAsync(CancellationToken stoppingToken)
    {
        var invites = await _clerkApiClient.Organizations["org_abc1234"].Invitations.GetAsync(x =>
        {
            x.QueryParameters.Status = "pending";
        });
    }
}

Standalone Client

If you want to use the client by itself, install Clerk.Net and call ClerkApiClientFactory.Create, passing in your secret key.

The returned client should be treated as a singleton and created once for the lifetime of your application.

HttpClient Customization

If you need to configure the underlying HttpClient used by the client, you can do in one of two ways:

• Configure the IHttpClientBuilder returned by AddClerkApiClient.
• Pass in a custom HttpClient instance to ClerkApiClientFactory.Create

Testing

For unit testing, see Unit testing Kiota API clients.

What about JWT Auth?

You might have stumbled upon this repo looking for a solution for validating Clerk JWTs, so I'll include the answer here for completion. Configuring JWT auth for Clerk is a tad unusual as they want you to validate the azp parameter instead of specifying an audience. This claim isn't normally validated at the authentication layer, and so you'll need some extra code to get things working:

builder.Services.AddAuthentication(JwtBearerDefaults.AuthenticationScheme)
    .AddJwtBearer(x =>
    {
        // Authority is the URL of your clerk instance
        x.Authority = builder.Configuration["Clerk:Authority"];
        x.TokenValidationParameters = new TokenValidationParameters()
        {
            // Disable audience validation as we aren't using it
            ValidateAudience = false,
            NameClaimType = ClaimTypes.NameIdentifier
        };
        x.Events = new JwtBearerEvents()
        {
            // Additional validation for AZP claim
            OnTokenValidated = context =>
            {
                var azp = context.Principal?.FindFirstValue("azp");
                // AuthorizedParty is the base URL of your frontend.
                if (string.IsNullOrEmpty(azp) || !azp.Equals(builder.Configuration["Clerk:AuthorizedParty"]))
                    context.Fail("AZP Claim is invalid or missing");

                return Task.CompletedTask;
            }
        };
    });

If you're sending requests from a SPA, it should call Clerk-JS's getToken as part of its HTTP middleware and append the token (prefixed with Bearer) to the Authorization header, for example:

async onRequestInit({ requestInit }) {
    requestInit.headers = {
        ...requestInit.headers,
        Authorization: `Bearer ${await getToken()}`
    }
}

If the requests are coming from an SSR environment (ie NextJS), then you can either use the session JWT via the __session cookie and forward it on, or use a JWT template to create a unique JWT for your scenario.

Inbound Clerk Webhooks

If you're accepting webhooks from Clerk, you will need to validate the incoming webhook signature. To do this, you'll need to install the Svix package:

dotnet add package Svix

Then, you can use the following code to validate the webhook signature:

    [HttpPost("webhook")]
    public async Task<IActionResult> ClerkWebhook(IConfiguration configuration)
    {
        // Retrieve the Clerk webhook secret from the configuration
        var clerkWebhookSecret = configuration["Clerk:WebhookSecret"];

        // Read the request body
        var json = await new StreamReader(HttpContext.Request.Body).ReadToEndAsync();

        // Retrieve the Svix headers
        var svixId = Request.Headers["svix-id"].ToString();
        var svixTimestamp = Request.Headers["svix-timestamp"].ToString();
        var svixSignature = Request.Headers["svix-signature"].ToString();

        if (string.IsNullOrEmpty(svixId) || string.IsNullOrEmpty(svixTimestamp) || string.IsNullOrEmpty(svixSignature))
        {
            return BadRequest("Missing headers");
        }

        // Attempt signature verification with the raw signature
        var wh = new Webhook(clerkWebhookSecret);
        WebHeaderCollection headers = new WebHeaderCollection
        {
            { "svix-id", svixId },
            { "svix-timestamp", svixTimestamp },
            { "svix-signature", svixSignature }
        };

        Event webhookEvent;
        try
        {
            wh.Verify(json, headers); // Verify doesn't return anything, just verifies the signature and throws if it's invalid
            webhookEvent = JsonSerializer.Deserialize<Event>(json); // Deserialize the JSON into an Event object
        }
        catch (Svix.Exceptions.WebhookVerificationException ex)
        {
            return BadRequest("Invalid signature");
        }
        catch (Exception ex)
        {
            return BadRequest("An error occurred");
        }

        switch (webhookEvent.Type)
        {
            case "user.created":
                // Handle user created event
                break;
            case "user.updated":
                // Handle user updated event
                break;
            case "user.deleted":
                // Handle user deleted event
                break;

            default:
                return BadRequest("Unhandled event type");
        }

        return Ok();
    }

    // Define the Event class to represent the webhook event
    public class Event
    {
        public string? Type { get; set; }
        public ClerkUser? Data { get; set; }
    }

    public class ClerkUser
    {
        public string Id { get; set; }
        public string? ExternalId { get; set; }
        [JsonPropertyName("first_name")]
        public string? FirstName { get; set; }
        [JsonPropertyName("last_name")]
        public string? LastName { get; set; }
        [JsonPropertyName("email_addresses")]
        public List<ClerkEmailAddress> EmailAddresses { get; set; } = new List<ClerkEmailAddress>();
    }

    public class ClerkEmailAddress
    {
        [JsonPropertyName("email_address")]
        public string? EmailAddress { get; set; }
    }

Disclaimer

I am not affiliated with nor represent Clerk. All support queries regarding the underlying service should go to Clerk Support.