---
title: "sdk/dotnet"
description: ".NET 8 server SDK for networkless JWT verification, ASP.NET Core request authentication, and webhook signature validation."
locale: "en"
---

> Documentation Index
> Fetch the relevant documentation index at: https://vonvon.id/sdks/llms.txt
> Use this file to discover all available pages before exploring further.

# sdk/dotnet

## Status

Implemented and verified locally. Real IdP round-trip verification (JWKS fetch, token sign/verify against a live Vonvon instance) has not been performed yet and must be completed before production use.

Registry status: UNPUBLISHED. Install this SDK only from the repository source checkout; do not use an external package registry.

Request authentication is Bearer-only by default. An application-owned JWT cookie is read only when its exact name is configured. The opaque \_\_Host-vonvon.rt.\* Core cookie is never scanned or verified locally; exchange it by forwarding the complete Cookie header to exact same-origin POST /v1/sessions/token with redirects disabled, and accept only a response containing the token field.

## Install

.NET 8 target required.

```xml
<ItemGroup>
  <ProjectReference Include="../vonvon/sdk/dotnet/Vonvon.csproj" />
</ItemGroup>
```

## ASP.NET Core setup (recommended)

```csharp
// Program.cs
using Vonvon;

builder.Services.AddVonvon(options =>
{
options.Issuer   = "https://vonvon.id";
options.Audience = "your-client-id"; // optional
});
```

## Authenticate a request

```csharp
// Controller / Minimal API
public class MyController(VonvonClient vonvon) : ControllerBase
{
[HttpGet("/me")]
public async Task<IActionResult> GetMe()
{
    var auth = await vonvon.AuthenticateRequestAsync(
        authorizationHeader: Request.Headers.Authorization);

    if (!auth.Authenticated)
        return Unauthorized(auth.Reason);

    return Ok(new { sub = auth.Claims!.Sub, email = auth.Claims.Email });
}

private Task<string> ExchangeSessionAsync() => vonvon.ExchangeSessionTokenAsync(
    $"{Request.Scheme}://{Request.Host}{Request.Path}",
    Request.Headers.Cookie.ToString());
}
```

## Verify token directly

```csharp
using Vonvon;

var client = new VonvonClient(new VonvonOptions { Issuer = "https://vonvon.id" });

try
{
var claims = await client.VerifyTokenAsync("eyJ...");
Console.WriteLine($"sub={claims.Sub} email={claims.Email}");
}
catch (TokenVerificationException ex)
{
Console.WriteLine($"Invalid token: {ex.Message}");
}
```

## Verify webhook

```csharp
app.MapPost("/webhooks/vonvon", async (HttpRequest req, VonvonClient vonvon) =>
{
using var ms = new MemoryStream();
await req.Body.CopyToAsync(ms);
var body = ms.ToArray();

var headers = new Dictionary<string, string>
{
    ["svix-id"]        = req.Headers["svix-id"].ToString(),
    ["svix-timestamp"] = req.Headers["svix-timestamp"].ToString(),
    ["svix-signature"] = req.Headers["svix-signature"].ToString(),
};

var webhookSecret = Environment.GetEnvironmentVariable("VONVON_WEBHOOK_SECRET")
    ?? throw new InvalidOperationException("VONVON_WEBHOOK_SECRET is required");

try
{
    var webhook = vonvon.VerifyWebhook(body, headers, secret: webhookSecret);
    return Results.Ok();
}
catch (WebhookVerificationException ex)
{
    return Results.BadRequest(ex.Message);
}
});
```

## VonvonOptions

| Property | Default | Description |
| --- | --- | --- |
| `Issuer` | required | Vonvon issuer URL |
| `Audience` | `null` | Expected aud claim; null skips validation |
| `JwksTtl` | 1 hour | JWKS in-memory cache TTL |
| `SessionCookieName` | `disabled` | Application-owned JWT cookie name; disabled unless explicitly configured |
| `ClockSkew` | 5 minutes | JWT exp/nbf clock skew tolerance |
| `WebhookToleranceWindow` | 5 minutes | Webhook replay prevention window |

## VonvonClient API

| Method | Description |
| --- | --- |
| `VerifyTokenAsync(token, ct)` | Verify JWT string; throws `TokenVerificationException` on failure. |
| `AuthenticateRequestAsync(authHeader, cookies, ct)` | Extract and verify token; returns `AuthStatus`; does not throw. |
| `VerifyWebhook(payload, headers, secret)` | Validate webhook signature; throws `WebhookVerificationException` on failure. Synchronous. |

## Platform notes

- Uses `Microsoft.IdentityModel.Tokens` and `System.IdentityModel.Tokens.Jwt` 8.x. ES256 is primary; RS256 and PS256 are supported.
- `AddVonvon()` registers `VonvonClient` as a singleton and wires `IHttpClientFactory` for JWKS fetching.
- Exception hierarchy: `VonvonException` -&gt; `JwksException`, `TokenVerificationException`, `WebhookVerificationException`.

Source: https://vonvon.id/sdks/dotnet/index.mdx