Stirling PDF

Stirling PDF is a comprehensive, open-source PDF manipulation tool that runs in the browser. It handles virtually every PDF operation a researcher or civic worker needs: merging and splitting documents, compressing large files, converting between formats (PDF to Word, Excel, images, and vice versa), adding OCR text layers to scanned documents, signing documents, removing pages, adding watermarks, and dozens more. For Indian researchers working with government documents — which are overwhelmingly PDF-based — Stirling PDF is the Swiss Army knife. It can be self-hosted (Docker) for organisations that handle sensitive documents and don’t want to upload them to random web services. Free, open-source, actively maintained on GitHub with 40K+ stars.