← PDF compressor

Compress a PDF in PHP

Make a PDF smaller by downsampling its images. Choose how far: screen (smallest), ebook, printer or prepress. Here is the whole call in PHP, with the output it produced when we ran it.

Before you start

• An API key. Create a free account; it comes with free tokens every month. Put the key in an environment variable so it stays out of your code: export BLOODWEB_KEY=your_key
• PHP 7.4 or later with the curl extension, which most installs have.
• The input file in the same folder: scan.pdf. Use your own; that is the name the code expects.

The code

Save it as pdf-compress.php and run php pdf-compress.php.

<?php
$ch = curl_init('https://bloodweb.net/api/v1/pdf-compress');
curl_setopt_array($ch, [
    CURLOPT_POST           => true,
    CURLOPT_HTTPHEADER     => ['Authorization: Bearer ' . getenv('BLOODWEB_KEY')],
    CURLOPT_POSTFIELDS     => [
        'file' => new CURLFile('scan.pdf'),
        'level' => 'ebook',
    ],
    CURLOPT_RETURNTRANSFER => true,
    CURLOPT_TIMEOUT        => 120,
]);
$body   = curl_exec($ch);
$status = curl_getinfo($ch, CURLINFO_RESPONSE_CODE);
if ($body === false) {
    exit(curl_error($ch) . "\n");
}
if ($status !== 200) {
    exit($status . ': ' . json_decode($body, true)['error']['message'] . "\n");
}
file_put_contents('smaller.pdf', $body);

What you get

Tested 19 October 2026: this exact code ran against our test copy of the API, which runs the same service code as bloodweb.net, and produced this.

It writes smaller.pdf: a PDF, 3 pages, 1 KB.

Change the call

Every option the PDF compressor takes. Add or change them the same way as the ones in the code.

• level: screen: images at 72 DPI, smallest. ebook: 150 DPI, good for email. printer: 300 DPI. prepress: 300 DPI, colour kept for print shops. One of: screen, ebook, printer, prepress.
• grayscale: Convert everything to shades of grey. Often halves a scanned colour document again.

If it fails

A failed call is not charged. The answer is JSON with an error object; the code above prints its message. The usual ones:

• 401 missing_key or invalid_key: BLOODWEB_KEY is not set in the shell that runs the code, or the key was revoked.
• 415 unsupported_type: the file is not a type this service reads. The type is read from the file itself, so renaming a file does not change it.
• 413 file_too_large: the file is over the limit on the service page.
• 402 insufficient_tokens: the balance does not cover the call. Top up in the dashboard.
• 429 rate_limited: too many calls at once. Wait the seconds in the Retry-After header and send it again.

Every code and its fix is in the docs.

Next

• The PDF compressor page: every option, the limits, and Try it now in your browser.
• Getting started: keys, errors and rate limits for all the services.