About Docento.app
Docento.app is a free PDF editor that runs entirely inside your web browser. You can sign, annotate, fill, and compress documents without creating an account and without your files ever leaving your computer.
Why we built it
Signing a single-page form used to mean printing it, signing with a pen, scanning it back in, and emailing the result. The web fixed that, but most of the tools that fixed it introduced a new problem: to edit your document, you first have to upload it to somebody else’s server. For a birthday invitation that’s fine. For an employment contract, a lease, a medical intake form, or a tax document, it’s a genuinely uncomfortable trade.
We started Docento.app in 2025 on a simple premise: modern browsers are powerful enough that this trade is no longer necessary. Rendering a PDF, drawing a signature onto it, and writing the file back out are all things your own machine can do. So that is where we do them.
How the “we never see your files” claim actually works
This is the part of the site we most want you to be skeptical about, so here is the mechanism rather than the marketing.
When you drop a PDF onto the editor, the file is read by your browser into memory using the standard File API. It is rendered to a canvas by PDF.js, Mozilla’s open-source PDF renderer, and your edits are written back into the document by pdf-lib. Both libraries run as JavaScript on your device. When you click Export, the finished file is assembled in memory and handed to your browser’s download mechanism.
At no point in that sequence is there a request that carries your document to us, because there is no upload endpoint to carry it to. You can verify this yourself without taking our word for it: open your browser’s developer tools, switch to the Network tab, and edit and export a file. You will see the page assets load and nothing resembling your document go out. You can also disconnect from the internet entirely after the page has loaded — the editor keeps working, which would be impossible if the processing happened on a server.
The practical consequence is that we cannot recover a file for you, cannot see what you signed, and have nothing to hand over if someone asks us for your documents. Those are limitations, and we think they are the right ones for this kind of tool.
What the site is
Two things, really:
- The tools. A PDF editor for signing, adding text, stamps, images, and annotations, and a PDF compressor for getting oversized files under an attachment limit. Both are free, both work without an account, and both run locally.
- The library. A growing reference covering how PDFs actually work — the format’s internals, accessibility and tagging, encryption and redaction, conversion, forms, print and colour handling, and troubleshooting — alongside a Document Workflow section on the habits around documents: writing them clearly, circulating them for review, and keeping the record findable.
How this is paid for
Docento.app is funded by display advertising. We do not charge for the tools, we do not sell a premium tier, and we have no analytics business on the side — we do not collect your documents, so there is nothing there to sell even if we wanted to.
Advertising is disclosed rather than disguised: ad units are visually distinct from editorial content and are never dressed up as recommendations or article text. Our Privacy Policy covers what advertising partners can and cannot see, and the cookie banner lets you decline personalised advertising while continuing to use every feature of the site.
Who writes the articles
Articles are written and maintained by the The Docento.app Team — the same people who build the editor. Working on PDF tooling means spending a lot of time inside the specification and inside the failure cases, and the library exists largely because we kept writing the same explanations to the same questions.
Our Editorial Policy sets out how articles get written, checked, corrected, and updated, and how we handle the fact that we are describing a category of software we also happen to make.
Getting in touch
Corrections, bug reports, feature requests, and press enquiries are all welcome. Use the contact page or email contact@docento.app. If you have found an error in an article, please say which one — we would rather fix it than leave it up.