SynTools is a free online toolkit: JSON formatting, Base64/URL encoding, regex testing, text diff, timestamps, UUID and password generation, hashing, QR codes, colour and base conversion, Markdown preview, image compression, PDF merge/split/encrypt, and in-browser Word/Excel/PPT editing — all processed on the client, so files never leave the browser.
Every tool above computes locally in your browser; files and text are never uploaded. A desktop build is available for fully offline use.