CaptureKit 0.1.0

CaptureKit .NET SDK

The official .NET SDK for the CaptureKit screenshot API.

Capture websites as PNG, JPEG, WebP or PDF, extract their content, or analyse them with AI.

The SDK exposes 7 typed async methods, one per documented endpoint (with required properties checked at compile time), plus a generic RequestAsync.

Requirements

• .NET 8 or newer

Installation

dotnet add package CaptureKit

Get your API key

Sign up for CaptureKit or sign in, then copy your API key from the dashboard. new CaptureKitClient() reads the CAPTUREKIT_API_KEY environment variable.

Quick start

using CaptureKit;

using var client = new CaptureKitClient();
var response = await client.ContentAsync(new ContentParams { Url = "https://example.com" });
Console.WriteLine(response.Json);

Parameter classes mirror the API reference. Use response.Deserialize<MyType>() to map the JSON onto your own types.

Binary responses

Endpoints that return a file (image, PDF…) give you the bytes; IsJson tells both cases apart:

var response = await client.CaptureAsync(new CaptureParams { Url = "https://example.com", Format = "png" });
if (!response.IsJson)
{
    await File.WriteAllBytesAsync("screenshot.png", response.Bytes);
}

Async jobs

Any call accepts is_async: true (useful past the 60-second server limit): the response is then a job_id. WaitForJobAsync polls GET /v1/jobs/{id} until a terminal status (CompletedJob, Error, NotFound, BadRequest):

var submitted = await client.ContentAsync(new ContentParams { Url = "https://example.com", IsAsync = true });
var job = await client.WaitForJobAsync(
    submitted.Json.GetProperty("job_id").GetString()!,
    onProgress: j => Console.WriteLine($"{j.GetProperty("status")} {j.GetProperty("progress")}%"));

GET or POST

Methods use GET when the endpoint supports it (query string). POST sends the same parameters as JSON:

await client.AnalyzeAsync(new AnalyzeParams { Url = "test" }, new RequestOptions { Method = "POST" });

Any endpoint

var response = await client.RequestAsync("GET", "/v1/usage");

Errors

try
{
    await client.ContentAsync(new ContentParams { Url = "https://example.com" });
}
catch (CaptureKitApiException exception)
{
    Console.Error.WriteLine($"{exception.StatusCode}: {exception.Message}");
}

All of them derive from CaptureKitException. Caller cancellation surfaces as OperationCanceledException.

Retries

Requests are retried up to 3 times after a network error, a 408, 500, 502, 503 or 504, or a rate limit — which the API returns as 401 (or 429) with a Rate limit exceeded message. Per-key quota errors (…: quota daily) are not retried, nor are 400, 402, 404 or client-side timeouts. The delay starts at 1 second and grows 1.5× per retry (capped at 30 seconds); a Retry-After header wins.

using var client = new CaptureKitClient(new CaptureKitClientOptions { MaxRetries = 5, RetryDelay = TimeSpan.FromMilliseconds(500) });
await client.ContentAsync(new ContentParams { Url = "https://example.com" }, new RequestOptions { MaxRetries = 0 }); // one request without retries

Batch requests

BatchAsync runs a function per item with at most 10 in flight (concurrency) and returns one BatchResult per item, in input order. A failing item never stops the others.

string[] inputs = { "https://example.com", "https://www.capturekit.dev", "https://github.com" };
var results = await client.BatchAsync(inputs, (value, ct) =>
    client.ContentAsync(new ContentParams { Url = value }, cancellationToken: ct), concurrency: 5);
foreach (var result in results)
{
    if (result.Ok)
    {
        Console.WriteLine(result.Value!.Json);
    }
    else
    {
        Console.Error.WriteLine($"{inputs[result.Index]}: {result.Error!.Message}");
    }
}

Configuration

using var client = new CaptureKitClient(new CaptureKitClientOptions
{
    ApiKey = Environment.GetEnvironmentVariable("CAPTUREKIT_API_KEY"),
    Timeout = TimeSpan.FromSeconds(60), // default 120 s
    HttpClient = myHttpClient,           // optional, you keep ownership
});

Endpoints

7 methods, generated from the OpenAPI document.

License

MIT — see LICENSE.