REST API

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SecuMailer has a REST API for sending secure emails. Both the GDPR and the NTA 7516 functionality are fully accessible via this API.

The API is documented with OpenAPI specification 3.0.1.

The REST API has webhook functionality, which means that the SecuMailer platform can communicate email events with an HTTPS endpoint of the sender.

SMTP API

The SMTP API is usually the simplest integration option for many backend applications because backend applications often have a provision for an SMTP client on board.

We have successfully integrated for customers with Salesforce, SAP and Centric. We have also successfully integrated with patient file systems such as Medisoft Dossier Manager.

GraphQL API

The SecuMailer platform offers insight into email events. This can be done on the basis of a (push) webhook call (see REST API above) and on the basis of a (pull) GraphQL endpoint.

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eIDAS Qualified Registered Email

The smarter alternative to a registered letter: faster, safer, and more cost-effective

Why wait for a registered letter to be delivered when you can send a legally binding, fully compliant message in seconds? With SecuMailer’s eIDAS Qualified Registered Email, you get the same legal status as a registered letter but

SecuMailer is the only Dutch qREMS provider on the EU Trusted List.
Delivering the highest level of trust for legally binding registered email, recognised across all EU member states.

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e-IDAS

Legal Certainty

Same legal status as a registered letter, recognised EU-wide.

Safe time

Type, send, and deliver instantly, no postal delays.

Cut Costs

Reduce costs by up to 10x compared to physical registered post.

Stay compliant

100% GDPR, NTA 7516, and eIDAS proof. All data stays within the EU.

Why Choose Qualified Registered Email?

When a message needs to hold up in court, standard secure email isn’t enough. eIDAS Qualified Registered Email gives you the legal certainty, speed, and cost savings your organisation needs without compromising privacy or ease of use.

Perfect for legal notices, government decisions, financial statements, contracts, compliance notifications, and any communication where proof of delivery is critical.

How registered mail with SecuMailer works

From send to secure in three seamless steps.
Step 1

Write and send

Write your message in your usual email client, such as Outlook, Microsoft 365, or Google Workspace. Simply send it with one click.

Step 2

Qualified timestamp and proof generation

As part of the delivery process, the message is sealed with a qualified electronic timestamp and every step, from sending to delivery to receipt, is logged in a tamper-proof audit trail. This process makes your email legally valid.

Step 3

Recipient authentication

The recipient receives a notification and authenticates their identity. After that, the registered email is delivered directly to their inbox. This ensures the message reaches the right person, securely and verifiably

Step 4

Direct inbox delivery

Once authentication is complete, the email is delivered directly to the recipient’s inbox. Once it’s delivered, the email is removed from our server.

Step 5

Proof of delivery

Both sender and recipient receive confirmation of delivery including proof that holds up in court.

Want more technical detail?

Explore our documentation

Features of registered email

Product Features

  • Email from your own email environment
  • Delivery to the recipient’s mailbox
  • Every email always secure
  • Delivery without portal intermediaries
  • No additional installation or extra software required
  • Works with all email clients
  • Works on all devices
  • Integration with back-office systems possible
  • Delivery receipt available
  • Functional / shared mailboxes possible
  • Custom branding applicable
  • Standard attachment size up to 40MB
  • Send up to 5TB with SecuFiler
  • Integration with any professional mail server
  • Implementation based on existing features
  • Security based on existing features
  • Security based on transport rules
  • API integrations available
  • (Audit) logging available
  • Two-factor authentication based on SMS
  • SAML / SSO available for the management environment
  • GDPR
  • Data minimization
  • ECSO (European Cyber Security Organization)
  • ISO 27001
  • NEN 7510
  • NTA 7516
  • eIDAS
  • ISAE 3000 SOC 2 Type 2
  • Personal service
  • Easily reachable by phone
  • Service commitment: uptime 99.95%
  • Service and support from 9-17
  • Self-service portal
  • Monthly SLA reports

Proven across sectors where every delivery counts

Where legal certainty and privacy matter — SecuMailer delivers.

Municipalities

Municipalities

Formal decisions, objection procedures

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Health-Care

Healthcare providers

Medico-legal communications.

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Finance

Legal professionals

Contracts, notarial deeds

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Legal

Financial institutions

Audit-proof delivery.

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Government

Education & regulators

Certified communication

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Features at a glance

Discover what makes SecuMailer scalable, seamless, and future-ready.

No software installs, familiar email clients, no portals

📬 DeliveryAlways-encrypted, one-time 2FA, NTA 7516-compatible

Inbox-first delivery, fallback for 2%, attachments up to 40MB

Full audit trail, proof of delivery, SLA reporting

REST & SMTP APIs, connects with back-office systems

Shared mailboxes, house style retained, device-agnostic

It’s just like registered mail – but it works like email.

Legal professionals, healthcare providers and municipalities rely on us every day.

ECSO

SecuMailer is recognized as a European cybersecurity solution under the ECSO label.

Ready to share and manage sensitive data securely?

Seamless, secure email that respects privacy, meets legal standards, and feels effortless—for both your team and the people you serve.

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