I shipped a website-to-PDF SaaS on WordPress — here's the stack

Last month I launched Site2PDF — converts any website to PDF, PNG, JPG or ZIP. Here's the entire tech stack, because the choices might be useful if you're building something similar.

What it does

Paste a URL → get a PDF of the whole page (or the whole site). Free plan gives 5 archives/month, all formats, cookie banner removal. Paid starts at $9/mo for 15 archives and 200 pages per site.

The stack

Frontend: a custom WordPress theme. Yes, WordPress. Hear me out.

Native user accounts, sessions, roles
Native admin panel for analytics and user management
Customizer for site branding
Gutenberg-free, just PHP templates + SCSS + vanilla JS

Rendering: Node.js + Puppeteer running on the same VPS, called from PHP via proc_open. A bash-like pattern:

$command = sprintf(
    '%s %s %s %s --options-file %s',
    escapeshellarg($node_path),
    escapeshellarg($script),
    escapeshellarg($url),
    escapeshellarg($output),
    escapeshellarg($options_json)
);
exec($command . ' 2>&1', $output, $code);

PHP passes options (cookie hide, selectors to expand, etc.) as a temp JSON file the Node script reads.

PDF assembly: pdf-lib for multi-page PDFs (each page becomes its own PDF page). DOMPDF for single-page fallback.

Image processing: sharp for PNG→JPG conversion. archiver for ZIP.

Billing: Paddle Billing (started with Stripe, had to migrate — Stripe doesn't support my country). Paddle handles tax, EU VAT, Canadian GST etc. — a huge win for a solo founder.

Auth: Google OAuth 2.0 without any plugin. A REST API endpoint redirects to Google, callback sets a one-time login token, cookie is set on the next regular page load. Why? Because iOS Safari blocks cookies set during REST API redirects (ITP).

Infra: Contabo VPS ($5/mo). Nginx, PHP-FPM, MariaDB. Chrome installed as google-chrome-stable, Puppeteer launches it with executablePath override.

Why WordPress (not Next.js or Rails)

The honest answer: I've shipped WP for 10 years. Familiar tools win. The theme is under 4000 lines of PHP, ~2000 lines of SCSS. I didn't need a full framework for ~5 pages and a wizard UI.

WordPress also gives me:

Zero-effort admin for users, plans, payment history
Free page hierarchy (/pdf-tools/full-page-screenshot/)
Built-in Yoast SEO and Site Icon features

The hot take: WordPress is a perfectly fine backend for a simple SaaS if you disable the bloat and write real code. Most of the "WordPress is slow" complaints come from bloated themes and 40 plugins.

Things that bit me

Puppeteer fullPage + fixed headers — writeup in my other post
Cookie banners blocking the screenshot — had to intercept requests to policy.cookiereports.com before page load
iOS Safari OAuth — first attempt set the auth cookie inside the callback redirect. Safari's ITP killed it. Had to use one-time tokens + set cookie on a regular page navigation.
iCloud Private Relay breaking CSRF state — used IP hash as the state key, which broke when Apple rotates IPs between redirects. Switched to state-as-key.
Paddle sandbox vs production — separate accounts, separate keys, separate price IDs. Wrote a helper that picks the right IDs based on WEBTOOLS_PADDLE_ENV constant.

The architecture in one diagram

Browser (vanilla JS)
  → AJAX → PHP (screenshot-tools.php)
          → proc_open → Node worker (Puppeteer)
          → writes PNG to /uploads/screenshot-temp/
          → PHP assembles PDF/ZIP if needed
          → returns base64 or job ID
  ← polls status / downloads blob

Full-site mode uses a different flow (background worker + status polling). Single-page mode is one synchronous AJAX call.