AddonMate

Datovka Lhůty

Every message in your official mailbox has a deadline. The extension finds it, adds it to your calendar, and reminds you before the deemed delivery period starts running.

Who it is for
Every company and sole trader (OSVČ) with an official mailbox, plus accountants managing client mailboxes
Price
CZK 99/month for the Pro plan, basic free
Launching
November 2026
Datová schránka · nová zpráva

Finanční úřad pro Středočeský kraj · Výzva k doplnění

do 15 dnů od doručení

Datovka Lhůty
Lhůta
6. 10. 2026 (Monday)
Doručeno
21. 9. 2026 · read
Co chtějí
supplement a VAT attachment for 8/2026
Připomínka
3. 10. by email

This is what an extension card looks like above the page you're working on. A demo, not real data.

What are you doing manually today

Every company and sole trader is legally required to have an official mailbox. A message is deemed delivered after 10 days, even if you haven't opened it, and from that moment, deadlines start running for appeals, supplements, or payment. Official letters are long, the deadline is hidden somewhere on the third page, and no one will remind you.

What the extension can do

  • Short summary of every message on datovka.gov.cz: who is writing, what they want, by when.
  • Finding the deadline in the text (e.g. "within 15 days of delivery") and calculating the exact date based on the delivery date.
  • Add the date to your calendar (Google, Apple, Outlook) with a single click.
  • Email reminder 3 days before the deadline and 2 days before the deemed delivery of unread messages.
  • Save the message as a PDF, including the delivery receipt, to a folder of your choice.
  • Overview of all active deadlines in one place, sorted by what is most urgent.
  • For accountants: switch between client mailboxes and view all deadlines in one shared overview.

How it looks

  1. 1

    Open the message

    On datovka.gov.cz as usual.

  2. 2

    You see the deadline

    Found in the text and calculated to a date.

  3. 3

    Add to calendar

    One click. The reminder comes automatically.

Price

Free

CZK 0

Message summary and deadline detection are free. The extension adds calendar entries, reminders, and an archive.

Pro

CZK 99 monthly, excluding VAT

All the features above. Cancel anytime, invoices are automatic. Those who reach out before launch get the first month free.

Privacy and security

The extension only works in your browser, on the mailbox you are logged into. We do not send message content to our servers. The summary is generated directly in Chrome (Chrome's built-in AI) or via your own AI key if you enter one. Only the deadline date goes to us for the reminder, if you enable it.

Rules that apply to all our extensions

Frequently asked questions

Do you see the content of my messages?

No. Messages stay in your browser. For the reminder, we only need the date and the title, which you choose yourself.

Does it work with Datovka, the app by CZ.NIC?

Datovka is a desktop program. Our extension works with the web mailbox on datovka.gov.cz, which most people use.

What if it doesn't find the deadline?

It will tell you. It never guesses. You can enter it manually and the reminder works just the same.

When will it launch and what if the date changes?

We're planning November 2026. We build in order of interest, so the launch date can shift by a month either way. Those who leave their email get a message on launch day.

I want Datovka Lhůty

Leave your email and get the extension on launch day, first month free. In the note, tell us what takes you the most time today — we'll build it around that.

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