Quick Overview
- The government automatically sets up a data box for business owners, without requiring an application and free of charge.
- A citizen who is not a business owner is not required to have a data box simply because they use a bank ID or the Citizen Portal.
- A message may be considered legally delivered even if you do not actually read it. Therefore, check your data box regularly and set up notifications.
- The obligation to submit a document electronically does not necessarily mean you must send it directly via the data box. You can also use the relevant government portal.
Not sure what the legal implications are of a message in your data box? Our legal advisory service will review its content and recommend the next steps.
Who will the government set up a data box for?
The requirement to have a data box by 2026 applies primarily to self-employed individuals and legal entities registered in the Register of Persons. This includes, for example:
- sole proprietors,
- business corporations,
- associations,
- foundations
- or homeowners’ associations.
The rules are governed by the Act on Electronic Transactions and Authorized Document Conversion. The government sets up the data box based on information from the relevant registries, so businesses generally do not need to submit an application.
Non-business citizens are not generally required to have a data mailbox. They may set one up voluntarily at no cost, for example, online using Citizen Identity or at a Czech POINT location.
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What should I do if I’m required to have a data box?
If the government sets up a data box for you by law, you do not need to apply for it. Your login credentials may be sent to your personal data box, if you have one, or by certified mail.
The data box becomes accessible upon the first login by an authorized person, but no later than the fifteenth day after the date of delivery of the login credentials. Therefore, it is not generally 15 days from the date of its creation. Delaying your first login will not prevent the delivery of official messages.
After logging in, set up notifications for new messages and choose how they are stored. If an accountant or another person is also supposed to check the mailbox, set up their own access with the appropriate permissions.
Can I refuse the data box?
If your data box was established by law, you cannot refuse it or have it deactivated simply because you do not want to use it. You may authorize another person to manage it, but this does not eliminate the legal consequences of delivery.
Different rules apply to a personal data box for a non-business citizen established upon request. In that case, you may request that access be disabled.
Simply logging in with a bank ID or using the Citizen Portal does not automatically create a data box for a non-business citizen.
How does delivery to a data box work?
All legal entities registered in the Commercial Register (business corporations and cooperatives), as well as attorneys, tax advisors, bailiffs, and insolvency administrators, are required to have a data box. It is also, of course, used by government agencies—such as government offices, courts, and similar entities.
A data box functions as a virtual mailbox—documents delivered to it have the same legal weight as a certified letter. If an individual or company owns a data box, government agencies and courts must deliver all documents to them through it. An essential part of communication via data boxes is also what is known as the “presumption of delivery.”
The rule is that once a message is delivered to your data box, you have ten days to read it. After that, the law presumes that you have reviewed the document, even if you haven’t logged into your data box at all. This has a significant impact, for example, on the timing of various deadlines for responding, filing appeals, and so on. It is therefore strongly recommended that you check your data box regularly and enable notifications, which alert you to every new message.
Starting in 2022, deemed delivery will also apply to private-law messages—for example, when two business owners communicate with each other. This typically applies to invoices, pre-litigation notices, and similar documents.
An unopened attachment does not suspend the deadline (example scenario): A business owner logs into the data box but puts off opening the attachment containing the decision until later. Nevertheless, the document may be deemed delivered simply by logging in, and the deadline for responding will begin to run according to the relevant rules. Therefore, verify the delivery date on the delivery confirmation, not based on when you opened the attachment.
Have you found a decision in your data box for which the deadline may have already passed? Contact our legal advice service. We will verify the delivery and assess what defense options are still available.
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Tip: We’ve covered the concept of ” fictitious delivery ” in detail in a separate article.
Which filings must you submit electronically in 2026?
Having a mandatory data box does not mean you must send every document through it. However, the law requires certain submissions to be made electronically.
- Tax Administration: A publicly accessible data box established by law creates an obligation to file forms electronically. For self-employed individuals, this applies to filings related at least partially to their business activities, such as income tax returns that include income from self-employment. You can also use the MOJE daně portal.
- Czech Social Security Administration (ČSSZ): Starting in 2025, self-employed individuals with an accessible data box established by law must submit required forms electronically, such as an overview of income and expenses. An exception may be granted in the event of duly justified technical problems.
- Health Insurance Company: Starting January 1, 2026, self-employed individuals must file their tax base summary electronically. This requirement is not contingent on whether they have a data box; the insurance company’s portal may also be used.
Adhere to the prescribed format and structure of the submission. Simply sending a scanned form via a data box may not meet the requirements.
How much does a data box and message storage cost?
A data box itself does not serve as a permanent archive. Messages are typically deleted automatically 90 days after a user authorized to read them logs in. Their retention is therefore not determined simply by the data box reaching its capacity.
Be sure to download important messages in a timely manner, including attachments and delivery receipts—ideally as the entire message in ZFO format. Another option is the paid Data Vault. Its price depends on capacity: for example, storing 20 messages costs 120 CZK per year, while capacity for 5,000 messages costs 29,500 CZK per year.
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Please note —unlike the data vault, however, the Citizen Portal does not guarantee the long-term verifiability of documents. This applies to standard downloads to a computer. In such cases, you must ensure the long-term verifiability of the documents yourself. You can check for free whether a document is still verifiable directly in the Data Box client portal, where you can also extend the validity of the timestamp on the message right away.
Is it worth setting up a data box in advance?
Yes and no. It depends more or less on your attitude toward data boxes and electronic communication in general. If you know you’ll be among those required to have a data box and don’t consider yourself a tech-savvy “geek,” you can set up your data box a little earlier on your own so that you can familiarize yourself with it well in advance—perhaps even with the help of experts—and configure everything calmly ahead of time. You’ll then be able to submit your tax return early next year without any stress and won’t have to worry about whether it might have gotten lost somewhere.
If electronic communication in various forms comes easily to you, then preparing ahead of time is probably unnecessary. Setting it up early won’t save you any significant amount of money, nor will it relieve you of any obligations. Of course, you can start enjoying the benefits that the electronic filing system offers sooner—you won’t have to wait in line at government offices, worry about office hours, or pay expensive postage.
Summary
The government automatically sets up a data box for business owners; legal entities registered in the Register of Legal Entities are also required to have one. Non-business citizens can set one up voluntarily. Once it’s active, it’s important to monitor incoming documents, set up notifications, and save messages in a timely manner. This is because delivery does not necessarily mean that the attachment has actually been read. Self-employed individuals must also comply with the rules for electronic filings with the tax authorities, the Czech Social Security Administration (ČSSZ), and, starting in 2026, health insurance companies as well. Communication with government agencies is free; however, private messages and additional services, such as the “Data Vault,” may incur fees.
Frequently Asked Questions
Who is required to use a digital signature?
The data box requirement applies to all legal entities (associations, foundations, business entities) and self-employed individuals. The government automatically sets up a data box for these entities by law. Ordinary citizens—individuals who are not self-employed—can set up a data box voluntarily, for example, online through the Citizen Identity portal. If you fall into a group subject to this requirement, you cannot avoid it; you may, however, delegate the management of the data box to another person.
How are tax returns and data boxes related?
If a data box was set up for you by law (for example, as a self-employed person), you must file your tax return via the data box or by other electronic means. In this case, the tax office will not accept a paper filing. However, if you have a data box only on a voluntary basis, the electronic filing requirement does not apply to you—you may still file your tax return in the traditional paper format.
What penalties might I face if I fail to comply with my data box obligations?
If the law requires you to use a data box and you ignore this requirement—for example, by failing to file your tax return electronically or by not responding to a message you’ve received—you may be fined. The Data Box Act also introduces the concept of “deemed delivery”—a document is considered delivered on the tenth day after it is placed in the data box, even if you have not logged in. That is why it is important to check your data box regularly.
How do I set up notifications for my data box?
To ensure you don’t miss an important message, we recommend turning on notifications for your data box. You can set up free email alerts or paid SMS messages. This way, you’ll be notified of every document received and avoid the inconvenience associated with deemed delivery.
How does the law regulate data boxes?
The rules are set forth in the Act on Electronic Transactions and Authorized Conversion of Documents, often referred to as the “Data Box Act.” This Act specifies who is required to have a data box, how delivery works, how deadlines are calculated, and what legal effects the data boxes have. If you want to know whether this requirement applies to you, this Act serves as the basis for determining that.
