FillBuddy

FillBuddy is a 100% client-side PDF annotation and form-filling web application. Users upload any PDF — including encrypted ones — annotate it directly in the browser using text, check marks, cross marks, strikeout lines, and signatures, then download the completed PDF.

Unlike competitors (Adobe, Smallpdf, iLovePDF), FillBuddy never uploads files to a server, never requires an account, and never adds watermarks. Its proprietary .fillbuddy save format preserves full editability of annotations — solving the widespread "tattoo problem" where other tools permanently bake edits into the PDF.

Built with a dual-engine architecture (pdf-lib for unencrypted PDFs, pdfjs-dist for encrypted ones), FillBuddy handles any PDF you throw at it while keeping your data completely private.