28 of our 30 PDF tools never touch a server. Here's how we built them

Regentflow — Tue, 20 Oct 2026 09:47:18 +0000

Most free PDF sites work the same way: you upload your file, their server does the work, and you download the result. That's fine for a menu. It's less fine for a payslip, a supplier contract or a staff ID scan.

When we built PDF Studio inside Regentflow, we set a rule: by default, the file never leaves the device. 28 of the 30 tools follow it completely. The other two have an optional AI feature, and they say so before it runs (more on that below).

The stack

Everything runs in the browser with four libraries:

pdf-lib for writing, merging, splitting and editing
@pdf-lib/fontkit for embedding fonts
pdf.js (pdfjs-dist) for rendering and parsing pages
SheetJS for Excel to PDF

The browser reads the file locally, the work happens in JavaScript on the page, and the result comes back as a download. There's no upload step, so there's nothing on a server to leak, keep or delete.

The two exceptions

Redact PDF has an optional "AI find" for scanned pages.
PDF Editor has an optional AI read and rewrite.

To read a scanned page, these send an image of that one page to our server and an AI model. They cost credits, never run automatically, and every other part of those tools stays local. We'd rather say this plainly than hide it in a privacy policy.

What's in it

Organise pages: merge, split, rotate, crop, page organizer, compare
Make it smaller: compress, flatten
Protect it: redact, watermark, metadata editor, inspect & clean
Edit and fill: PDF editor, fill & add text, e-sign, annotate, find & replace, form filler
Convert: image to PDF, PDF to images, PDF to text, PDF to Word, Excel to PDF
Extras: page numbers, headers & footers, extract & rebuild text, font detection, certificates, report builder, batch

What it costs

Every tool is free and unlimited. The one exception is the PDF editor: editing is free, and downloading the edited file costs A$1 (or A$5 for ten). Pro members get unlimited downloads.

Why a business-tools company built this

Regentflow is mostly team tools for cafes, bars and restaurants: stocktakes your whole team counts on their own phones, rosters built from staff availability, and free invoices. Our users kept leaving to fix a PDF somewhere else. Now they don't have to.