About DocStudio PDF
DocStudio PDF is a complete, open-source PDF toolkit that runs entirely inside your browser. There is no backend, no upload endpoint and no analytics pipeline: when you drop a file, it is read with the File APIs, processed with WebAssembly and handed straight back to you.
How it works
Two engines cooperate. pdf-lib assembles and edits documents (reordering pages, drawing overlays, writing metadata and encrypting files) and pdf.js renders and reads them (thumbnails, text extraction, raster export). qpdf-wasm repairs malformed cross-reference tables before editing, so files that other tools reject still open.
Principles
No signups. No uploads. Unlimited, unmetered use. Works offline. Self-hostable as a folder of static files. If a tool cannot be done losslessly in the browser, the limitation is stated on the page rather than hidden.