Someone on your team needs to merge three PDFs, redact a client name, and OCR a scanned contract. The usual move is a random "free PDF tool" website — upload the file, wait, download, hope they delete it from their servers, repeat for the next document. For a law firm intake form or a payroll packet, that's a bad habit.
Stirling-PDF is the self-hosted alternative that's actually stuck around. ~80k GitHub stars, 50+ tools in one web UI, and a REST API if you want to wire it into n8n or a custom script. Run it in Docker on your own server and PDFs never leave your infrastructure.
What it actually does
Stirling-PDF is a browser-based PDF workshop. Open the UI, pick a tool, drag files in, download the result. No desktop install required for end users — though they also ship desktop clients now if you want local-only processing.
The tool list is long enough that most teams stop paying for Adobe Acrobat tricks they use twice a year:
- Structure: merge, split, reorder pages, rotate, crop, remove blank pages
- Conversion: PDF ↔ Word/Excel/PowerPoint/images (LibreOffice under the hood on full images)
- Searchable scans: OCR via Tesseract — 100+ languages if you mount the tessdata volume
- Security: add/remove passwords, redact, flatten forms, strip metadata
- Signing: draw or upload signatures, certificate workflows in enterprise builds
- Automation: "pipelines" in the UI, plus Swagger-documented REST endpoints at
/swagger-ui/index.html
It's the kind of app you deploy once and then forget about until someone asks "is there a way to combine these without emailing them to a sketchy website?" — and there is, on your own domain.
Why self-host PDF tools?
Documents stay local. Contracts, medical forms, tax returns, HR files — uploading those to a third-party PDF SaaS means trusting their retention policy, their breach response, and whatever country their S3 bucket lives in. Self-hosting gives you a clear answer: the file touched your container, not someone else's analytics pipeline.
No per-seat Acrobat math. Adobe licenses add up when ten people occasionally need merge/OCR/compress. Stirling-PDF is open source; you pay for the server.
API for boring repetition. Invoice batches, report packs, onboarding packets — if the same merge/conversion runs weekly, hit the REST API from a cron job or n8n workflow instead of manual clicks.
Works on any device. Phone, tablet, laptop — it's a responsive web app. Handy for field staff who need a quick compress before emailing a scan, without installing anything.
What running it takes
Docker is the supported path. The current image lives at docker.stirlingpdf.com/stirlingtools/stirling-pdf (older docs still reference frooodle/s-pdf — check the repo for the tag you want):
docker run -d -p 8080:8080 \
-v ./configs:/configs \
-v ./logs:/logs \
--name stirling-pdf \
docker.stirlingpdf.com/stirlingtools/stirling-pdfPick an image variant based on what you need:
- latest (~500 MB) — full toolset, OCR, LibreOffice conversions. Default choice.
- ultra-lite (~200 MB) — merge/split/compress/rotate only. Good for small VPS or Pi if you skip OCR and Office conversion.
- fat (~700 MB) — extra fonts for Arabic, CJK, and other non-Latin scripts.
RAM: ultra-lite runs on 1 GB. Full image with OCR and concurrent conversions wants 2 GB+, especially if people upload large scanned PDFs at the same time. CPU spikes during OCR — that's Tesseract chewing through pages, not a bug.
Mount /configs so login settings and custom config survive container updates. Enable auth for anything on the public internet — set DOCKER_ENABLE_SECURITY=true so the security module loads, then configure users in the UI. An open Stirling-PDF instance is a free document conversion service for the whole internet.
HTTPS via nginx or Caddy in front. Back up the configs volume if you've set up authentication or custom pipelines.
Who it's for (and who should skip it)
Good fit: law and accounting firms, agencies handling client PDFs, HR teams processing signed forms, anyone who's tired of "just use this website real quick" for confidential documents.
Maybe skip it: if one person needs a single merge once a year — offline tools or a desktop app is fine. If you need full collaborative PDF editing (comments, track changes, real-time co-authoring), this isn't Adobe Acrobat. Stirling-PDF is manipulation and conversion, not a word processor with PDF skin.
Hosting it in Canada
We run Stirling-PDF on Canadian Docker hosting for clients who want internal PDF tools with TLS, auth, and backups — same stack as n8n, Uptime Kuma, and the rest of the self-hosted toolkit. Put it behind your VPN or SSO if the docs are sensitive; put it on a private subdomain if the whole office just needs merge and OCR without the SaaS upload dance.
Tell us how many users and whether you need OCR or Office conversion — we'll pick the right image variant and size the box honestly.
