README

The official PHP 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 methods, one per documented endpoint (with array-shape PHPDoc for static analysis), plus a generic request(). It sends requests through any PSR-18 client and uses Guzzle by default.

Requirements

PHP 8.1 or newer

Installation

composer require capturekitdev/sdk

Get your API key

Sign up for CaptureKit or sign in, then copy your API key from the dashboard. The client reads the CAPTUREKIT_API_KEY environment variable when no key is passed.

Quick start

<?php

require 'vendor/autoload.php';

use CaptureKit\Client;

$client = new Client(getenv('CAPTUREKIT_API_KEY') ?: null);
$response = $client->content(['url' => 'https://example.com']);
print_r($response->data);

Parameter arrays use the names of the API reference. Unknown names throw a SerializationException; use request() for undocumented parameters.

Binary responses

Endpoints that can return a file (image, PDF…) return a JsonResponse or a BinaryResponse:

use CaptureKit\BinaryResponse;

$response = $client->capture(['url' => 'https://example.com', 'format' => 'png']);
if ($response instanceof BinaryResponse) {
    $response->save('screenshot.png');
}

Async jobs

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

$submitted = $client->content(['url' => 'https://example.com', 'is_async' => true]);
$job = $client->waitForJob($submitted->data['job_id'], onProgress: static function (array $job): void {
    echo $job['status'], ' ', $job['progress'] ?? 0, "%\n";
});
print_r($job->data);

GET or POST

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

use CaptureKit\RequestOptions;

$client->analyze(['url' => 'test'], new RequestOptions(method: 'POST'));

null values are omitted, false and 0 are sent, and lists repeat the parameter name.

Any endpoint

$response = $client->request('GET', '/v1/usage');

Errors

use CaptureKit\Exception\ApiException;

try {
    $client->content(['url' => 'https://example.com']);
} catch (ApiException $exception) {
    echo $exception->status, ': ', $exception->getMessage();
}

Exception	When
`ConfigurationException`	Missing API key, invalid options or unsupported method.
`SerializationException`	A required parameter is missing, unknown or can't be sent.
`TransportException`	Network failure or timeout.
`ApiException`	Non-2xx status (`status`, `errorMessage`, `responseBody`, `rawResponse`).
`ResponseDecodingException`	A success response could not be decoded.

All of them extend CaptureKit\Exception\CaptureKitException.

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.

$client = new Client(null, ['max_retries' => 5, 'retry_delay' => 0.5]);
$client->content(['url' => 'https://example.com'], new RequestOptions(maxRetries: 0)); // one request without retries

Batch requests

batch() sends several calls with at most 10 requests in flight ($concurrency), through Guzzle's connection pool, and returns one BatchResult per call in input order. A failing call never stops the others. With a custom PSR-18 client the calls run one after another.

$inputs = ['https://example.com', 'https://www.capturekit.dev', 'https://github.com'];
$calls = array_map(static fn(string $value): array => ['content', ['url' => $value]], $inputs);

foreach ($client->batch($calls, concurrency: 5) as $result) {
    if ($result->ok()) {
        print_r($result->value->data);
    } else {
        echo $inputs[$result->index], ': ', $result->error->getMessage(), "\n";
    }
}

Constant	Default	Description
`Client::DEFAULT_CONCURRENCY`	`10`	Tasks run at the same time by batch
`Client::DEFAULT_TIMEOUT`	`120.0`	Request timeout (seconds)
`Client::MAX_RETRIES`	`3`	Retry attempts after a network error, a 408/5xx or a rate limit
`Client::RETRY_BACKOFF_FACTOR`	`1.5`	Exponential backoff multiplier
`Client::DEFAULT_RETRY_DELAY`	`1.0`	Delay before the first retry (seconds)

Options and custom HTTP clients

$client = new Client(null, [
    'timeout' => 60.0,               // seconds, default 120 (default Guzzle client only)
    'headers' => ['X-Trace' => 'abc'],
    'http_client' => $psr18Client,   // optional: any PSR-18 client
]);

Endpoints

7 methods, generated from the OpenAPI document.

Method	HTTP	Description
`analyze()`	GET / POST `/v1/analyze`	AI Content API analyzes any webpage and returns AI insights summary, value proposition, features, categories, use cases, and optional conta…
`capture()`	GET / POST `/v1/capture`	Browser-like Screenshot API that captures webpages as PNG/JPEG/WebP or PDF for previews, QA, reporting, monitoring, and archiving no headle…
`content()`	GET / POST `/v1/content`	CaptureKit Content API extracts structured webpage data, metadata, links, HTML/Markdown: in one request for SEO, monitoring, indexing and a…
`jobs()`	GET `/v1/jobs/{id}`	Poll the status, progress (0–100) and result of a job started with is_async=true. Polling is free. Poll until status is terminal: Completed…
`stats()`	GET `/v1/stats`	Infrastructure health for an engine or endpoint over the last hour. Not scoped to your account or tenant. Enabled per account: HTTP 403 mea…
`usage()`	GET `/v1/usage`	Retrieve real-time usage statistics and credit balance for your CaptureKit account.
`websiteCrawler()`	GET / POST `/v1/website/crawler`	Website Crawler API fetches raw HTML from any webpage in request mode (no rendering) for fast scraping, audits, monitoring, and link/metada…

All CaptureKit SDKs

SDK	Package	Install
Node.js	`@capturekitdev/sdk`	`npm install @capturekitdev/sdk`
Python	`capturekitdev`	`pip install capturekitdev`
Go	`capturekit-go`	`go get github.com/capturekitdev/capturekit-go`
.NET	`CaptureKit`	`dotnet add package CaptureKit`
Ruby	`capturekitdev`	`gem install capturekitdev`
PHP	`capturekitdev/sdk`	`composer require capturekitdev/sdk`
Java	`capturekit-java`	build from source, see its README
CLI	`@capturekitdev/cli`	`npm install -g @capturekitdev/cli`
MCP server	`@capturekitdev/mcp`	`npx -y @capturekitdev/mcp`

License

MIT — see LICENSE.

capturekitdev / sdk

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