There is a routine repeated every day in law firms, insurers, property management companies and town councils: print a letter, put it in an envelope, go to the post office, pay between three and five euros, keep the receipt and wait. Wait three to five days for delivery. Wait a few more for the acknowledgement of receipt. And file the paper, hoping never to need it.
That routine exists for a legitimate reason: without it, there is no proof. An ordinary email, when disputed, is worth little. The sender can claim they sent it, the recipient can claim they never received it, and neither can demonstrate much.
What has changed, and is still little known in Portugal, is that the law now accepts a digital alternative with the same weight. Not an approximate version. The same equivalence, written into law.
What exactly the law says
The framework rests on two pieces. The first is Regulation (EU) No 910/2014, known as eIDAS, which created the electronic registered delivery service and set out the requirements for it to be considered qualified (Articles 43 and 44). The second is Decree-Law No 12/2021 of 9 February, which implements that regulation in the Portuguese legal system.
It is in the Portuguese decree-law that the decisive sentence appears. The communication of data and documents through qualified electronic registered delivery services is equivalent to sending by registered post. And where there is confirmation of receipt by the recipient in identical form, the equivalence is with sending by registered post with acknowledgement of receipt.
It is worth rereading slowly, because every word counts.
"Qualified". A service that generates nice-looking receipts is not enough. The provider must be a qualified trust service provider, on the national trusted list, subject to audit and supervision by the National Security Office (Gabinete Nacional de Segurança). A provider not on that list may offer a useful service, but it does not produce legal equivalence.
"In identical form". For equivalence with the acknowledgement of receipt, the recipient's confirmation must be given within the same registered channel. It is the difference between knowing the message arrived and having proof, with the same value as an acknowledgement of receipt, that the recipient received it.
eIDAS also adds something many people do not know: data sent and received through a qualified service benefits from a presumption of integrity, of origin and of the accuracy of the date and time. In practice, the burden is reversed. It is not the sender who has to prove they sent it. It is whoever disputes it who has to rebut the presumption.
What changes in day-to-day operations
| Registered letter with acknowledgement of receipt | Qualified electronic registered delivery | |
|---|---|---|
| Evidential value | Yes | Yes, by legal equivalence |
| Proof of receipt | Yes, once the acknowledgement of receipt is returned | Yes, with confirmation in identical form |
| Time to delivery | Three to five working days | Seconds |
| Cost per item | Between three and five euros, plus printing and envelope | A fraction of that |
| Travel | Required | None |
| Hours | Post office hours | Twenty-four hours a day |
| Archive | Physical, in boxes, by year | Digital, searchable in seconds |
| Sending to one hundred recipients | An afternoon's work | A single send |
The row that usually decides it is not cost. It is the archive. Anyone who has had to find proof of a notice sent three years ago, in a box of old files, knows exactly what a two-second search is worth.
When this stops being convenience and becomes risk
Proof is not built when the dispute arrives. It is built at the moment of sending, or it does not exist at all. There are situations where that difference is the difference between winning and losing:
Formal notices and termination of contracts. The deadline runs from the notice. If the notice cannot be proven, neither can the deadline.
Communications to policyholders and claimants. Short deadlines, final consequences, and a recipient with every interest in claiming they never received anything.
Notices to terminate leases and communications between landlord and tenant. The form of the communication is often the first point attacked in court.
Notices of meetings of condominium owners and shareholders. A poorly evidenced notice of meeting can taint the resolutions that result from it.
Administrative notifications. For a public body, proof of notification is a condition for the act to take effect.
What to check before signing up
Not every service that presents itself as "certified email" has the same legal effect. Five questions separate what works from what only appears to:
- Is the provider qualified? Check whether it is on the national trusted list. It is public and can be checked in minutes.
- Is a certificate generated for each send? And does that certificate identify the sender, recipient, content, date and time, with a timestamp?
- Is there confirmation of receipt in identical form? That is the element that supports equivalence with the acknowledgement of receipt.
- How long does the proof remain accessible? Limitation periods in civil matters can go far beyond what a system's memory usually keeps.
- Where is all this hosted, and under which law? Proof that depends on infrastructure subject to a third-country jurisdiction brings with it a problem that is not about proof, it is about confidentiality.
Do the maths before deciding
The calculation is simple and usually settles the discussion. An organisation that sends two registered letters a week spends, on postage alone, somewhere between three hundred and five hundred euros a year. On top of that come paper, envelopes, toner and, above all, time: printing, folding, addressing, travelling, queuing, filing the receipt.
None of these items appears on an invoice labelled "cost of proof". But that is what they are.
The registered letter is not going to disappear, nor does it need to. What no longer makes sense is using it for lack of an alternative, when the alternative has been written into law since 2021.