What registered mail is for
People send registered letters to have evidence. If a dispute comes up later, the sender needs to show three things:
- What was sent, and that it hasn't been changed since
- When it was sent and received
- Who received it
Paper registered mail covers this with a post office receipt and a signed acknowledgement of receipt. Registered electronic mail provides the same proof with a digital record, and saves you a trip to the post office.
What is registered electronic mail?
A registered electronic mail is — you guessed it — a digitised version of the traditional registered letter. It proves that a specific document was sent, received and acknowledged at a specific point in time.
Under eIDAS Regulation Article 43.1, a registered electronic delivery service cannot be denied legal effect solely because it exists in electronic form. As long as the data transmitted is intact, timestamped and traceable, the proof holds.
How it differs from an ordinary email
A standard email confirmation proves that a message was sent. It says nothing about who opened it or whether the person who clicked is who they claim to be. Read receipts can also be switched off by the recipient, and there's no reliable way to show afterwards that an attachment wasn't altered.
What makes a proof of delivery reliable
When you compare services, look for four elements:
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- Content integrity. The service calculates a cryptographic fingerprint (a hash) of the document. Any later change to the file produces a different fingerprint and can be detected.
- A reliable time record. A qualified electronic timestamp records exactly when the document was sent and when receipt was acknowledged.
- Recipient identity. Proof that a document reached an email address is weaker than proof that an identified person acknowledged it.
- An audit trail. A complete record of every step: sending, notification, acknowledgement and delivery.
A working example: e-signature.eu with itsme
e-signature.eu offers registered electronic mail in which the recipient signs the acknowledgement of receipt with itsme. The process runs in four steps.
- The sender prepares the mail. The first time, the sender verifies their own email address, which then appears as the sender. They upload the document and enter the recipient's address. The document is immediately protected with a qualified electronic timestamp, and its cryptographic hash is embedded in the acknowledgement of receipt the recipient will be asked to sign.
- The recipient signs the acknowledgement of receipt with itsme. The recipient gets an email invitation and signs in the itsme app. Their identity is verified, and the acknowledgement is electronically signed and qualified-timestamped before the document itself is delivered.
- The document is delivered. Once the acknowledgement is signed, the recipient receives the content. The sender is notified immediately.
- The sender receives proof. The signed acknowledgement and the qualified timestamp are available straight away in the sender's dashboard, together with a full audit trail of the exchange.
Why the recipient's identity matters. When a recipient signs with itsme, the acknowledgement is tied to a verified identity. itsme is a qualified trust service provider under eIDAS. Its identity verification mechanism meets the standards required for this kind of proof to hold in front of a court or a third party.
A note on the legal level
e-signature.eu's registered electronic mail service relies on qualified components under eIDAS Articles 41 and 43 (a qualified electronic timestamp and an electronically signed acknowledgement of receipt). It is not a qualified registered electronic delivery service (REDS) under Article 44.
For the vast majority of professional and personal use cases, this distinction has no practical impact. A small number of specific national provisions may require a fully qualified REDS. If that applies to your situation, check the applicable rules before sending.
Checklist before you send
- Is there a required delivery method? Check whether the applicable rules or your contract prescribe one.
- Are you using the right address? Use an email address the recipient actually uses, ideally one they've given you for this kind of correspondence.
- Will you be able to find the evidence later? Download the signed acknowledgement and the audit trail and store them with the case file.
Who uses it, and for what?
For SMEs and freelancers:
- Formal notices to clients or suppliers
- HR notifications (warnings, dismissals, end of contract)
- Termination of commercial agreements
- Convening a general assembly
- Any official communication requiring proof of delivery
- Lawyers sending formal notices
- Accountants transmitting official documents
- Real estate agents issuing lease terminations or end-of-tenancy notices
For liberal professions:
- Lawyers sending formal notices
- Accountants transmitting official documents
- Real estate agents issuing lease terminations or end-of-tenancy notices
For private individuals:
- Terminating a lease or a subscription
- Filing a complaint with an insurer
- Contesting an invoice
- Formal notice to a neighbour, a landlord or a contractor
e-signature.eu is an eIDAS-compliant electronic signature and registered electronic mail platform, built for SMEs, freelancers and liberal professions across Europe. It runs on prepaid credits with no subscription and is available in FR, NL, EN, DE and ES.