Integrate eIDAS Registered Electronic Mail into Your Applications
The e-Signature.eu API sends your registered electronic letters with a Qualified Electronic Time Stamp and a signed acknowledgement of receipt, from a single endpoint. eIDAS compliant. No subscription.
Proof of receipt, automated inside your processes
One API call replaces the trip to the post office: document time-stamped, recipient notified, acknowledgement of receipt signed and evidence file assembled automatically.
Standard REST API
Documented RESTful architecture, compatible with all languages and frameworks. The same API key as for signatures — one integration to maintain.
Qualified Electronic Time Stamp
Every dispatch automatically receives a Qualified Electronic Time Stamp issued by a QTSP, attesting to the certain date and the integrity of the document (Art. 41 eIDAS).
Guaranteed integrity
A SHA-256 hash of the document is embedded in the time stamp. Any later modification is detectable — with no action required on your side.
Webhooks & callbacks
Your server is notified at every stage: letter viewed, acknowledgement of receipt signed, refusal or expiry of the deadline.
Universal credits
The same credits cover your signatures and your registered letters, at the same rates. No subscription, no fixed costs.
Audit Trail & dashboard
Every registered letter triggered via the API appears in your unified dashboard, with a time-stamped Audit Trail downloadable as a PDF.
You choose the level of identity proof
The acknowledgement of receipt is signed by the recipient. Select through the API the eIDAS level suited to what is at stake — rates are identical to those of signatures.
itsme®
Evrotrust
Veriff
OTP Email/SMS
⚖️ The higher the signature level, the stronger the recipient’s identification. Only a qualified electronic signature (QES) is legally equivalent to a handwritten signature under the eIDAS Regulation.
Three operations triggered by a single call
You send your files and the recipient’s details. The platform handles everything else.
📑 Merge & conversion
Your files — whatever their format — are merged and converted into a single secured PDF/A.
⏱️ Qualified Electronic Time Stamp
A QTSP applies a Qualified Electronic Time Stamp embedding the SHA-256 hash: certain date and protected integrity.
📬 Acknowledgement of receipt
Generated automatically with its legal wording, then signed by the recipient using the method you selected.
🛡️ Double protection, two distinct proofs
Qualified Electronic Time Stamp
Proves when and what — with its own legal presumption (Art. 41 eIDAS).
Signed acknowledgement of receipt
Proves received by whom — at the identification level you selected.
2 steps to integrate registered electronic mail
An API designed for simplicity: authenticate, send, and everything else arrives by webhook.
Authentication & submission
Your API key is available directly in your account, Signature API section. Send the subject of the letter, your files, the recipient’s details and the signature method chosen for the acknowledgement of receipt.
Acknowledgement & retrieval
The recipient is invited by email. As soon as they sign the acknowledgement of receipt, your server receives the status, the signed acknowledgement and the time stamp by webhook. A refusal or an expiry is notified the same way.
🧰 Developer resources
Postman collection
Import and run all endpoints in one click, with pre-configured examples.
Interactive documentation
Complete reference for parameters, responses, error codes and scenarios.
Callback URL
Set your callback URL to receive the status of the letter, the signed acknowledgement of receipt and the Audit Trail by webhook.
📌 What to know before integrating
- One recipient per registered letter — for several recipients, trigger as many dispatches.
- A 15-day deadline to sign the acknowledgement of receipt, with configurable automatic reminders.
- Until the acknowledgement is signed, the document is not delivered — you nonetheless keep the time stamp and the proof of invitation.
- Dispatch is irrevocable — it cannot be cancelled once triggered.
🔑 Ready to start? You can begin right now.
Order credits on e-signature.eu — your account is created automatically, and your API key and Callback URL are available in the Signature API section of your account. No access request, no waiting.
Wherever proof of receipt is required
Registered electronic mail fits in wherever your processes still impose a postal dispatch and its delay.
Formal notices & debt recovery
Trigger a time-stamped formal notice as soon as an invoice passes its due date, straight from your management tool.
Contract terminations
Leases, insurance, subscriptions — notify termination with proof of receipt, without printing or queuing at a counter.
HR & employment relations
Formal employer/employee communications, summons, contractual notifications — with full traceability.
Real estate & property management
Notices to quit, indexations, charge reminders and tenant notifications, automated from your management software.
Summons & corporate life
General meeting summons, notifications to partners and co-owners, sent in volume from your system.
Insurance & claims
Claim declarations, disputes and regulatory notifications, with an evidence file assembled automatically.
Signatures and registered letters in the same integration
Already integrating electronic signatures? Registered letters use the same API key, the same credits and the same dashboard.
✍️ Get your documents signed from the same applications
itsme®, Evrotrust, Veriff and OTP email/SMS, in classic or embedded mode. One API key, one credit balance, one dashboard for your signatures and your registered letters.
- Same credits, same rates as registered letters
- Multiple signatories and sequential signing flow
- Embedded mode: signing within your own application
Pay-as-you-go — no subscription
Top up credits as you need them. The higher your volume, the lower your cost per credit. The same credits cover your signatures and your registered letters.
1 registered letter = 1 recipient, whatever the number of documents delivered. The cost depends solely on the signature method chosen for the acknowledgement of receipt — from 0.4 credit. No monthly fees, no commitment.
Ready to integrate registered electronic mail?
Order credits to immediately access your API key and start your integration.