Stirling PDF: Self-Hosted PDF Toolkit Setup

At some point you need to do something to a PDF — merge two documents, split out specific pages, compress a scanned file that’s 40MB for no reason, convert a Word doc, add a signature. The usual solution is uploading the file to a website that offers to do this for free. The question you don’t ask is where that file goes after.

Stirling-PDF is a self-hosted web application that does all of that. 50+ PDF operations in a single Docker container, running locally, with nothing leaving your network.

What It Does

The feature list is long. The ones I use:

Merge PDFs — combine multiple files into one
Split PDF — extract specific pages or split at a page number
Compress — reduce file size by downsampling images and removing metadata
PDF to Word/Excel/Image — convert to editable formats
Word/Image to PDF — convert to PDF
Rotate, reorder pages — fix orientation issues from scanners
Add watermark — useful for documents you’re distributing
OCR — make scanned PDFs text-searchable (optional, requires extra setup)
Sign PDF — add a digital signature

There’s also a pipeline feature for chaining operations — compress then merge, for example — but I rarely use it for one-off tasks.

Installation

mkdir -p /opt/stirling-pdf

Create /opt/stirling-pdf/docker-compose.yml:

services:
  stirling-pdf:
    image: frooodle/s-pdf:latest
    container_name: stirling-pdf
    ports:
      - "8090:8080"
    volumes:
      - /opt/stirling-pdf/trainingData:/usr/share/tesseract-ocr/5/tessdata
      - /opt/stirling-pdf/extraConfigs:/configs
      - /opt/stirling-pdf/logs:/logs
    environment:
      - DOCKER_ENABLE_SECURITY=false
      - INSTALL_BOOK_AND_ADVANCED_HTML_OPS=false
      - LANGS=en_GB
    restart: unless-stopped

DOCKER_ENABLE_SECURITY=false — Disables the login system. Fine for a homelab where access is controlled at the network level. If you want login-based access control, set this to true and configure user accounts.

INSTALL_BOOK_AND_ADVANCED_HTML_OPS=false — Skips some heavier optional features (Calibre integration for ebook conversion). Set to true if you want those.

LANGS=en_GB — The language pack for OCR. en_US or en_GB for English. You can add more language packs if you’re processing documents in other languages.

Start It

cd /opt/stirling-pdf
docker compose up -d

Access the web interface at http://YOUR_SERVER_IP:8090. It’s available immediately — no setup wizard, no account creation required (with security disabled).

Basic Operations

The interface is a grid of operation tiles. Click the one you need, upload files, configure options, download the result.

Merging PDFs:

Click Merge PDFs > upload two or more files > drag to reorder if needed > Merge. The download starts automatically.

Compressing:

Click Compress PDF > upload the file > choose compression level (low/medium/high — “medium” is usually the right balance) > Compress.

For a typical scanned document, medium compression reduces a 15MB file to 2–3MB without visible quality loss on screen. High compression for documents where file size matters more than image quality.

Splitting:

Split by Pages — enter page ranges (e.g., 1-5,6-10) to extract those ranges as separate PDFs. Split by Chapter — splits at each bookmark/chapter marker (useful for ebooks converted to PDF). Split Every X Pages — for when you need to split a large document into equal chunks.

OCR (Making Scanned PDFs Searchable):

Click PDF OCR > upload the scanned PDF > select your language > run. This adds a hidden text layer to the PDF so you can search the content and copy text. The original scan remains visible; OCR adds the searchable layer underneath.

Note: OCR is CPU-intensive. A 20-page scanned document might take 30–60 seconds on a mini PC. That’s fine for occasional use.

Adding Authentication

If you want to put Stirling-PDF behind a login (useful if you’re exposing it via a reverse proxy):

    environment:
      - DOCKER_ENABLE_SECURITY=true
      - SECURITY_ENABLE_LOGIN=true
      - SECURITY_INITIALLOGIN_USERNAME=admin
      - SECURITY_INITIALLOGIN_PASSWORD=changeme

After first login, change the password in the admin panel.

Behind a Reverse Proxy

Stirling-PDF works fine behind Nginx Proxy Manager. Add a proxy host pointing to port 8090. Enable SSL. No special configuration needed.

If you have authentication enabled in Stirling-PDF, you don’t need additional auth at the proxy level — the built-in login handles it.

Privacy Considerations

With DOCKER_ENABLE_SECURITY=false and no reverse proxy auth, anyone who can reach port 8090 on your network can use Stirling-PDF. On a home network where you trust all connected devices, that’s fine.

If you’re exposing it externally (via a subdomain), add authentication — either Stirling-PDF’s built-in login or Nginx Proxy Manager’s basic auth.

Keeping It Updated

cd /opt/stirling-pdf
docker compose pull
docker compose up -d

Stirling-PDF is under active development and releases frequently. The update is safe — your uploaded files aren’t stored between sessions (each operation is stateless), so there’s no migration concern.

The Alternative

The alternative to Stirling-PDF is googling “merge PDF free” and uploading your documents to whatever site appears. Some of those sites are fine. Some of them are not. Stirling-PDF is faster for the operations you run regularly (once it’s bookmarked) and the files stay local. For documents that contain anything you’d be uncomfortable having a stranger read — financial documents, medical records, contracts — that matters.