Stirling-PDF: Self-Hosted PDF Toolkit for Merging, Splitting, and OCR

Why Stirling-PDF?

Every time you upload a PDF to an online tool, your data passes through a third party. Stirling-PDF keeps everything local:

30+ PDF operations in one interface.
Zero data leakage — files never leave your server.
No accounts or limits — unlimited usage, no watermarks.
REST API — automate PDF processing from scripts.
Dark mode — beautiful modern UI.

Prerequisites

Docker on any machine.
At least 256 MB RAM (more for OCR).

Step 1: Deploy with Docker

docker run -d \
  --name stirling-pdf \
  -p 8080:8080 \
  -v ./training-data:/usr/share/tessdata \
  -v ./configs:/configs \
  -e DOCKER_ENABLE_SECURITY=false \
  frooodle/s-pdf:latest

Access at http://your-server:8080.

Step 2: Available Operations

Category	Operations
Page Operations	Merge, split, rotate, rearrange, remove, extract pages
Conversion	PDF ↔ Word, Excel, PowerPoint, images, HTML, Markdown
Compression	Reduce file size with quality options
Security	Add/remove password, permissions, watermark
OCR	Extract text from scanned PDFs (Tesseract)
Manipulation	Add page numbers, headers/footers, flatten forms
Signing	Add signature image to PDF

Step 3: API Integration

Every operation is available via REST API:

# Merge two PDFs
curl -F 'fileInput=@file1.pdf' \
     -F 'fileInput=@file2.pdf' \
     http://localhost:8080/api/v1/general/merge-pdfs \
     -o merged.pdf

# Compress a PDF
curl -F 'fileInput=@large.pdf' \
     -F 'optimizeLevel=3' \
     http://localhost:8080/api/v1/general/compress-pdf \
     -o compressed.pdf

# OCR a scanned PDF
curl -F 'fileInput=@scanned.pdf' \
     -F 'languages=eng+spa' \
     http://localhost:8080/api/v1/misc/ocr-pdf \
     -o searchable.pdf

Stirling-PDF vs Online Alternatives

Feature	Stirling-PDF	ILovePDF/SmallPDF
Privacy	Files stay on your server	Uploaded to cloud
Cost	Free, no limits	Free tier limited
Operations	30+	20+
API	Yes, REST	Paid plans only
Watermarks	None	Free tier adds watermarks
OCR	Included (Tesseract)	Paid feature

Troubleshooting

Problem	Solution
OCR produces poor results	Install additional language packs in `/usr/share/tessdata`
Large files timeout	Increase Docker memory limit and timeout settings
”File too large” error	Set `STIRLING_PDF_MAX_FILE_SIZE` environment variable
API returns 500	Check Docker logs: `docker logs stirling-pdf`

Summary

One Docker command for a complete PDF toolkit.
Privacy first — no cloud uploads, no third parties.
REST API for automation from scripts and workflows.
Replaces paid subscriptions to ILovePDF, SmallPDF, or Adobe.

Frequently Asked Questions

What is Stirling-PDF and why use it?

Stirling-PDF is a self-hosted web application for PDF manipulation. It replaces online tools like ILovePDF, SmallPDF, and Adobe Acrobat for common tasks: merging, splitting, compressing, converting, OCR, watermarking, and more. Your files never leave your server, making it ideal for sensitive documents like invoices, contracts, and medical records.

What PDF operations does Stirling-PDF support?

Over 30 operations: merge, split, rotate, compress, convert (Word/Excel/images to/from PDF), OCR text extraction, add/remove passwords, watermark, sign, rearrange pages, extract images, add page numbers, flatten forms, and more.

Does Stirling-PDF require an API key or account?

No. Stirling-PDF is completely free with no accounts, API keys, or usage limits. All processing happens locally on your server. You can optionally enable authentication to restrict access.

Can I integrate Stirling-PDF with other tools via API?

Yes. Stirling-PDF exposes a REST API for every operation. You can call it from scripts, n8n workflows, or any HTTP client. For example: curl -F 'fileInput=@doc.pdf' http://localhost:8080/api/v1/general/compress-pdf -o compressed.pdf