Signed Reader

Open a .zfo file

Someone sent you a .zfo from a Czech data box (datová schránka)? Drag it here to read the message, save the attachments and check the signature.

Works with .p7s, .p7m, .asice, .bdoc, .edoc, .adoc, .sce, .asics and .zfo

Viewing and checking are free. Downloads start at $3.99.

How it works

  1. Add the file

    Drag it onto the page, or tap to pick it from your phone or computer.

  2. Read it

    You see the document, who signed it, and whether anything changed after signing.

  3. Download

    Save the original document, a PDF with a signature report attached, or both.

Your file stays on your device. We open it right here in your browser, and once the page has loaded it works even with Wi-Fi off.

Simple pricing

Opening a file, reading it and checking the signatures costs nothing. You only pay if you want to download.

This document
Every download for this file
$3.99
1 year
As many documents as you like for 12 months
$12.99
Lifetime
As many documents as you like, for good
$24.99

Pay once and download straight away. No subscription, no account. If the file doesn’t open properly, you get a refund within 14 days.

About the format

A .zfo file is a message or delivery receipt saved from the Czech government’s data box system (ISDS). It is an XML file, signed by the system itself, that holds the message details and any attachments.

Questions people ask

Do I need Datovka or 602XML Filler?

No. The message opens right in your browser, on a phone or a Mac too.

Why are there no attachments?

You probably have a delivery receipt (doručenka). It describes a message but doesn’t contain its files, so open the message .zfo itself.

Is my file uploaded?

No. The message is opened on your device, so its contents stay with you.

Is the PDF I download still signed?

Not by itself. The signature belongs to the .zfo file, and the PDF is the document that was inside it. Keep the original .zfo if you may have to prove who signed. The “PDF with signature report” download adds a page that records who signed, when, and what the check found.

What does “Certificate not recognized” mean?

It’s about who issued the certificate, not about the document. The certificate doesn’t come from an authority on the EU trusted lists or the ICP-Brasil list, which are the ones we check. That happens with company, test or very old certificates. Whether the document changed after signing is shown on its own line, just above.

Other formats