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Guide

What is a REM — registered email — under eIDAS

The digital equivalent of registered post with proof of delivery: evidence of who sent what, to whom and when — with the legal value the eIDAS Regulation gives it.

In short

An electronic registered delivery service (ERDS) transmits data between parties and produces evidence of each step: that the message was submitted, by whom, when it was made available to the recipient and when the recipient received it. It also protects the content against loss, theft, damage or alteration.

A REM (Registered Electronic Mail) is an electronic registered delivery service that runs over ordinary email, following the European standards ETSI EN 319 532. The recipient gets the email in their usual mailbox; the provider keeps and delivers the evidence, electronically signed or sealed.

When the service is provided by a qualified trust service provider and meets the requirements of Article 44 of eIDAS, it is a qualified electronic registered delivery service (QERDS) — and its evidence enjoys a legal presumption in every Member State.

The legal definition

Regulation (EU) No 910/2014 (the eIDAS Regulation), Article 3, defines:

(36) ‘electronic registered delivery service’ means a service that makes it possible to transmit data between third parties by electronic means and provides evidence relating to the handling of the transmitted data, including proof of sending and receiving the data, and that protects transmitted data against the risk of loss, theft, damage or any unauthorised alterations;
(37) ‘qualified electronic registered delivery service’ means an electronic registered delivery service which meets the requirements laid down in Article 44. Regulation (EU) No 910/2014, Article 3(36) and (37) — consolidated text on EUR-Lex

Legal effect (Article 43)

  1. Non-discrimination. Data sent and received using any electronic registered delivery service cannot be denied legal effect or admissibility as evidence in legal proceedings solely because it is electronic or because the service is not qualified.
  2. Legal presumption — qualified service only. Data sent and received using a qualified service enjoys the presumption of:
    • the integrity of the data;
    • the sending of that data by the identified sender;
    • its receipt by the identified addressee; and
    • the accuracy of the date and time of sending and receipt indicated.

In practice: with a qualified service, whoever disputes the evidence must prove it wrong. With a non-qualified service the evidence is admissible, but whoever relies on it may have to demonstrate its reliability.

Requirements for the qualified service (Article 44)

A qualified electronic registered delivery service must:

  1. be provided by one or more qualified trust service providers;
  2. ensure with a high level of confidence the identification of the sender;
  3. ensure the identification of the addressee before the delivery of the data;
  4. secure the sending and receiving of data by an advanced electronic signature or advanced electronic seal of a qualified provider, so as to preclude undetectable changes;
  5. clearly indicate to the sender and addressee any change of the data needed for sending or receiving it;
  6. indicate the date and time of sending, receiving and any change by means of a qualified electronic time stamp.

Where data is transferred between two or more qualified providers, these requirements apply to all of them.

What changed with eIDAS 2

Regulation (EU) 2024/1183, in force since 20 May 2024, amended Article 44:

Those acts came with Commission Implementing Regulation (EU) 2025/1944 of 29 September 2025 (in force since 20 October 2025). It refers to ETSI EN 319 521 (provider requirements), EN 319 522 (architecture, semantics and evidence formats), EN 319 401 and EN 319 411-1.

Registered delivery, REM and qualified — what is the difference?

Electronic registered delivery (ERDS)Qualified (QERDS)
Legal basisArt. 3(36); Art. 43(1)Art. 3(37); Arts 43(2) and 44
ProviderAny trust service providerQualified provider, supervised and listed in the EU trusted lists
Value of evidenceAdmissible as evidencePresumption of integrity, sending, receipt and date/time
RecognitionLeft to the court's assessmentThroughout the EU

REM is not a third legal category: it is how registered delivery is provided over email (ETSI EN 319 532). A REM may or may not be qualified — that depends on the provider and the service.

Evidence and the ASiC container

Throughout the delivery, the provider issues standardised evidence (ETSI EN 319 522), for example:

Each piece of evidence identifies sender, recipient, date and time, the message identifier and the content's fingerprint (hash), and is sealed by the provider. To deliver everything in a single verifiable file, many providers use an ASiC container (Associated Signature Container, ETSI EN 319 162): a ZIP file bundling the original message, the evidence and the signature or seal covering them. That is the file you can validate here. Learn more in How it works.

How to confirm a provider is qualified

  1. Look the provider up in the EU trusted lists through the European Commission's eIDAS Dashboard. The service must appear with the type Qualified electronic registered delivery service and the status granted.
  2. Or check our list of qualified registered delivery providers, extracted automatically from the trusted lists.
  3. Qualified providers may use the EU trust mark for qualified trust services.
  4. In Portugal, trust service providers are supervised by the Gabinete Nacional de Segurança (Decree-Law 12/2021).

This page summarises the eIDAS Regulation for information purposes. It is not legal advice; only the text published in the Official Journal of the European Union is authentic.