snapdok

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Take a full-page screenshot in PHP with cURL extension

"full_page": true captures the whole document, not just the viewport — the render scrolls the page, waits for lazy-loaded images along the way, and returns one tall image. width sets the viewport width the page lays itself out at; height is measured, not guessed.

Below is a complete, runnable PHP program using cURL extension, no third-party dependency needed. It reads your API key from the SNAPDOK_KEY environment variable — free keys take about thirty seconds and need no card.

<?php
$body = json_encode([
    'url' => "https://your-app.com/report/42",
    'format' => "png",
    'full_page' => true,
    'width' => 1280,
]);

$ch = curl_init("https://snapdok.io/v1/render");
$headers = [];
curl_setopt_array($ch, [
    CURLOPT_POST => true,
    CURLOPT_POSTFIELDS => $body,
    CURLOPT_RETURNTRANSFER => true,
    CURLOPT_TIMEOUT => 90,
    CURLOPT_HTTPHEADER => [
        'Authorization: Bearer ' . getenv('SNAPDOK_KEY'),
        'Content-Type: application/json',
    ],
    CURLOPT_HEADERFUNCTION => function ($ch, $line) use (&$headers) {
        $parts = explode(':', $line, 2);
        if (count($parts) === 2) $headers[strtolower(trim($parts[0]))] = trim($parts[1]);
        return strlen($line);
    },
]);

$bytes = curl_exec($ch);
$status = curl_getinfo($ch, CURLINFO_RESPONSE_CODE);
curl_close($ch);

if ($status !== 200) {
    throw new RuntimeException("snapdok error $status: $bytes");
}
file_put_contents('full.png', $bytes);
echo ($headers['x-page-height'] ?? '?') . " // measured document height in CSS px\n";

Very tall pages hit a documented cap rather than an out-of-memory surprise: images are cut off at 20,000 CSS px, and the response says so explicitly — X-Full-Page-Truncated: 1 plus X-Page-Height with the real document height. If you need everything past the cap, ask for "tile": true and the render returns a ZIP of overlapping numbered tiles instead (covered in its own guide, linked below).

Sticky headers are the classic full-page artifact — a bar designed to follow the viewport can repeat down a scrolled capture. If a page renders oddly, try "wait_until": "networkidle" first so animations and late images settle before the scroll pass.

Same endpoint, one more trick: if the page you are rendering has a form on it, adding "pdf_forms": true to a PDF render brings it back with real, fillable AcroForm fields — a PDF people can type into, not a picture of one. How that works.

Notes for cURL extension

Plain ext-curl, no Composer needed. The details that bite: CURLOPT_RETURNTRANSFER must be set or the bytes are echoed to stdout instead of returned; the HTTP status has to be read explicitly with curl_getinfo() because cURL happily "succeeds" on a 401; and response headers need a CURLOPT_HEADERFUNCTION callback if you want to check things like X-Form-Fields. file_put_contents is binary-safe in PHP — strings are byte arrays — so no "b" flag dance is needed.

Response headers worth reading

HeaderMeaning
X-Page-HeightFull document height in CSS px.
X-Full-Page-Truncated1 when the image stops at the 20,000 px cap.
X-Full-Page-Max-HeightThe cap itself.

Full parameter reference: the docs. Hard numbers on caps and timeouts: limits.

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