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An open-source alternative to Adobe Acrobat

Stirling PDF is the one project in our catalog listed as a replacement for Adobe Acrobat. It is documents software with 95.4K GitHub stars. Below is how it measures against the questions people usually ask first.

Stirling PDF

Documents

Merge, split, compress, OCR, sign and redact PDFs on your own server.

Stirling PDF replaces a pile of single-purpose online PDF sites and desktop licences with one web app on your own server. Staff can merge, split, compress, convert, OCR, sign and redact documents without uploading them to a third party, and developers can reach the same operations through an API.

  • Merge, split, rotate, compress, watermark, sign and redact PDFs from a browser interface.
  • Run OCR and convert between PDF, Office files, HTML and images on your own server.
  • Call the same tools from your own systems through a REST API with built-in Swagger docs.

What people use it for

Assemble and shrink a document bundle

Drop several PDFs into Merge, put them in order, then add page numbers and run Compress. You get one smaller file that is ready to email or upload to a portal.

Redact a file before sharing it

Open Redact and black out names, account numbers or whole areas of the page, then run Sanitize to strip embedded JavaScript and attachments. The cleaned copy can go to a client or auditor.

Make scanned paperwork searchable

Upload scanned invoices or contracts, run OCR in the language of the documents, then convert the result to PDF/A for long-term archiving. Extra OCR languages can be added to the mounted tessdata folder.

95.4K starsMITTypeScriptLatest release 7 days agoWebsite ↗Full profile →

Fact checklist

The same questions the pages with more alternatives let you sort by, answered for Stirling PDF.

  • Permissive licence (MIT, Apache, BSD)Licence: MIT (permissive)
  • Open-source licence (copyleft or permissive)Licence: MIT (permissive)
  • Released in the last 90 daysLatest GitHub release Oct 24, 2026 (7 days ago)
  • Does not meet: Gaining stars this weekNot enough star history yet to tell
  • Written in TypeScriptMain language on GitHub
  • Recommended in a stackIn Law firm, Medical clinic, Accounting firm, Real estate agency

Data from GitHub and our catalog. Every listing is hand-approved. List prices are what the vendor publishes, not a quote, and self-hosting has its own running costs.