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The Zynyo API

With our REST API or SOAP API, you can easily interface with your own software. The link is rich in functionality that allows your employees and customers to work more efficiently and sign documents reliably and according to European legislation within minutes.


  • Ready for testing within seconds
  • API is available for free for testing; as long as needed
  • 100% legal from a secure environment

Available functionalities include

  • Signing with different types of authentication means: e.g. with mouse, SMS-TAN, iDIN or a (PKI) certificate in the cloud
  • Automatic follow-up: signatories can automatically receive an e-mail or SMS with a reminder if the document to be signed is not signed within a predefined time. This e-mail and SMS are configurable.
  • Bulk signing: Signers who need to sign several documents have the option to sign them in one operation.
  • Act of signature: The PKI certificate ('eSeal' or electronic seal) and the Audit Trail are attached to the signed document guaranteeing legal validity. It is also possible to receive the Audit Trail separately from the signed document. Both documents are then sealed with the PKI certificate and provided with an identical (hash) code for easy archiving.
  • Template: the possibility to send documents for signing where the signatory still has to fill in certain fields and/or tick a (mandatory) field, e.g. text fields, labels, date fields, selection fields, drop down lists.
  • Initialling: initialing documents on each page.
  • eSealAlso called 'electronic sealing'. Sealing documents with a eSeal which makes it impossible for the recipient to alter these documents and gives the recipient certainty about the identity of the sender. This prevents fraud with documents.
  • LTV: Zynyo ensures the highest level of long-term validation, allowing for secure archiving of document signatures.
  • Internal approval: Allow an approver to first accept or reject a document before it is sent out to be signed by the other parties.

API Documentation

This documentation is intended for developers who want to integrate the Signing Service into their (web) application. To be able to use it, you need an API key; you can request this via our contact form. Click on one of the buttons for the documentation and our WSDL of the latest versions.

SOAP API v3.5 WSDL v3.5


Do the Zynyo Check!

Check whether your software is already Zynyo-ready and whether digital signing is already integrated in the packages you use. Fill in your package(s) and your e-mail address and you will receive a response immediately.