Self-hosted PDF tools: Stirling-PDF vs PDFDing vs Paperless-AI
Edit, organise and auto-tag PDFs without uploading them to online converters. A practical comparison of three self-hosted PDF tools you can deploy on Railway.By chin · Oct 4, 2026 · 4 min read
Online PDF tools are convenient until you remember what you are uploading: contracts, invoices, IDs, medical letters. Self-hosting gives you the same convenience with the files staying on infrastructure you control.
"PDF tool" covers three quite different jobs, and each template here is built for one of them:
| Job | Template | In one line |
|---|---|---|
| Merge, split, compress, convert, OCR | Stirling-PDF | Private online-converter replacement |
| Keep and read a PDF library | PDFDing | Clean PDF manager and viewer |
| File paperwork automatically | Paperless-AI | Paperless-ngx plus AI tagging |
Stirling-PDF: the Swiss Army knife
Stirling-PDF is one of the most popular self-hosted apps there is, and with good reason. It bundles dozens of PDF operations into one web interface:
- merge, split, reorder, rotate and delete pages
- compress large files
- convert to and from images, Office formats and HTML
- add or remove passwords and watermarks, and sign documents
- OCR, to make scanned documents searchable and selectable
Processing happens on your server, not on a third-party site.
Settings worth knowing:
LANGScontrols the OCR languages. Add the languages of your scanned documents for better text recognition.- The template mounts a volume at
/usr/share/tessdata, where OCR language data lives, so downloaded language packs survive redeploys. DOCKER_ENABLE_SECURITYturns on Stirling-PDF's login system. Enable it before sharing the URL. Otherwise anyone who finds the domain can use your server's resources.
Stirling-PDF has no database. Files are processed and returned, not stored, which keeps it simple and cheap to run.
PDFDing: a calm home for your PDFs
PDFDing solves a different problem. It is where you keep PDFs you come back to: papers, manuals, ebooks, statements. You upload files, organise them with tags, and read them in a built-in viewer that works on desktop and mobile. It remembers where you left off in each document.
Settings worth knowing:
- Uploaded files live on a volume mounted at
/home/nonroot/pdfding/media, so your library survives redeploys. HOST_NAMEshould match the domain you use (for example a custom domain) so logins and links work correctly.SECRET_KEYsigns sessions. Use a long random value and keep it private.
PDFDing is lightweight: a single service with no external database to manage.
Paperless-AI: a document archive that files itself
If you deal with lots of paperwork (receipts, bills, letters, tax documents), you probably want Paperless-ngx. It is a full document management system that OCRs everything you give it and makes your archive searchable. Paperless-AI adds an AI layer on top. It reads each new document and suggests a title, tags, correspondent and document type, so filing happens automatically.
This template is the biggest of the three. It deploys:
- Paperless (Paperless-ngx itself)
- Postgres and Redis, which Paperless needs
- paperless-ai, the AI tagging service
Each service with data has its own volume.
Setting it up:
- The template asks for
PAPERLESS_ADMIN_PASSWORD. This is the password of the first Paperless admin account, so make it strong. - Sign in to Paperless and create an API token for the paperless-ai service.
- Open the paperless-ai web interface and complete its setup: connect it to Paperless with that token and choose an AI provider (OpenAI, or an OpenAI-compatible endpoint).
- Upload a few documents and review the suggested tags before letting it run on your whole archive.
AI tagging sends document text to the model provider you choose. For sensitive archives, use a provider whose data policy you are comfortable with, or a self-hosted model endpoint.
Which one do you need?
- "I need to compress this PDF and merge these scans." Stirling-PDF.
- "I want one place to read and organise my PDFs." PDFDing.
- "I want my paperwork scanned, searchable and filed automatically." Paperless-AI, which includes Paperless-ngx.
Many people run Stirling-PDF together with one of the other two. They solve different problems and do not overlap much.
Security checklist for document apps
Document tools hold sensitive files, so take five minutes before sharing a link:
- Turn on authentication (
DOCKER_ENABLE_SECURITYfor Stirling-PDF; the others have accounts built in). - Use strong, unique admin passwords and keep the generated secrets private.
- Keep volumes attached, since that is where your files live, and consider periodic exports or backups of important archives.
- Use a custom domain with HTTPS (Railway issues certificates automatically).
Frequently asked questions
Are my files uploaded anywhere else?
Stirling-PDF and PDFDing process and store files only in your own deployment. Paperless-AI sends document text to the AI provider you configure, so choose it deliberately.
Can Stirling-PDF OCR scanned documents in languages other than English?
Yes. Add the languages you need with the
LANGS variable.Do I need Paperless-ngx experience to use Paperless-AI?
No, but it helps to skim the Paperless-ngx docs on tags and correspondents, because that is the structure the AI fills in for you.
Templates in this guide
paperless-AI
Includes Postgres + Redisautomatically analyze and tag your documents from paperless-ngx
25 deploys
DeployMore guides
- Build a self-hosted Perplexity alternative with Morphic, SearXNG and FirecrawlSelf-host an AI answer engine with cited sources. Compare Morphic, Open DeepResearch and Fireplexity, and add private search with SearXNG or Whoogle.
- How to self-host Excalidraw with real-time collaborationRun your own Excalidraw whiteboard with live, end-to-end encrypted collaboration on Railway. Covers how the two services fit together, setup, and common fixes.
- Self-hosted ChatGPT alternatives: Open WebUI vs LibreChat vs big-AGICompare three open-source ChatGPT-style interfaces you can self-host on Railway, where each one stores your chats, and which to pick for you or your team.